Thèses sur le sujet « Facial cue »

The tendency for humans to give preferential attention to animate agents in their immediate surroundings has been well-documented and likely reflects an evolved specialization to a persistent adaptive problem. In uncertain or ambiguous cases, this tendency can result in an over-detection of animacy, as the potential costs of failing to detect an animate agent far outweigh those of mistaken identification. In line with this, it seems likely that humans have evolved a sensitivity to specific cues which are indicative of animacy such that the mere presence of these cues will lead to detection, regardless of the objective category membership of the entity in question. There exists a wealth of research speaking to this effect with regards to motion cues, specifically in terms of the capacity for self-propulsion and goal-directed action. Morphological cues have also been implicated - most especially the presence of facial features – as they specify a capacity for perceptual feedback from the environment, which is essential for goal-directed motion. However, it remains an open question as to whether the capacity for animacy detection is similarly sensitive to facial information in the absence of motion cues.

The experiments reported here attempted to address this question by implementing a novel task in which participants were asked to judge the animacy or inanimacy (or membership in animal or object categories) of different images: animals with and without visible facial features, and objects with and without visible facial features. Beyond replicating a general advantage for detecting animate agents over inanimate objects, the primary predictions for these experiments were that facial features would have a differential effect on performance, such that they would improve performance when visible in animals, and would hinder performance when visible in objects. Experiments 1a and 1b provided a preliminary confirmation of this pattern of responses using images of familiar and unfamiliar animals (e.g., dogs versus jellyfish), and unaltered images of objects with and without faces. Experiment 2 improved on the design of this task by more closely matching the sets of images (the same animals facing toward or away from the camera, and objects with faces which had been digitally altered to disrupt the facial features), and by changing the prompt of the task from yes/no judgments of animacy to categorization into animal or object groups. Experiment 3 examined the face inversion effect, or the failure to recognize familiar faces when their orientation is inverted, on animal-object categorization. Lastly, experiments 4 and 5 attempted to extend the findings from experiment 2 to preschool-aged children, by implementing a card sorting task (experiment 4) and a computerized animal detection task (experiment 5). The results of this series of experiments highlight the prominent role of facial features in detecting animate agents in one’s surroundings.

Social judgments of facial appearance may reflect that individual’s physical condition. In this thesis, I present empirical studies investigating social judgments of facial appearance and their underlying physiology. The first empirical chapter investigates the relationship between social judgments of women’s facial appearance and their salivary cortisol levels and body mass index (BMI). Faces of women with lower BMI were rated as more attractive, healthier, and more feminine. By contrast with previous research, social judgments of women’s faces were not related to their salivary cortisol, however. These results suggest that the type of health information reflected in women's faces includes qualities indexed by BMI, but does not necessarily include qualities indexed by cortisol. In my second empirical chapter, I investigated the interrelationships among a composite measure of men's actual threat potential (derived from measures of their upper-body strength, height, and weight) and composite measures of these men's perceived facial and vocal threat potential (derived from dominance, strength, and weight ratings of their faces and voices, respectively). Although men's perceived facial and vocal threat potential were positively correlated, men's actual threat potential was related to their perceived facial, but not vocal, threat potential. Consistent with other recent work on cues of men’s threat potential, these results present new evidence that men's faces may be a more valid cue of these aspects of threat potential than their voices are. Whereas Chapters 2 and 3 arguably focused on the possible role of face shape characteristics in communicating information about physical condition, Chapter 4 focused specifically on facial coloration. In Chapter 4, I investigated the effects of manipulating color cues in White UK and Chinese faces on White UK and Chinese participants’ judgments of attractiveness and health. By contrast with the cross-cultural similarity between White UK and Black African participants’ responses to facial coloration reported in previous studies, I found cultural differences in the effects of facial coloration on Chinese and White UK participants' facial attractiveness and health judgments. While both Chinese and White UK participants preferred faces with increased lightness and redness, Chinese participants had stronger preferences for lightness and White UK participants had stronger preferences for redness. More strikingly, while Chinese participants preferred faces with decreased yellowness, White UK participants preferred faces with increased yellowness, and this effect was not qualified by face ethnicity. These results suggest that preferences for facial coloration are not necessarily universal, but can differ across cultures. The research reported in this thesis suggests that faces contain information about body size (Chapters 2 and 3). They also show that responses to facial color cues, a putative cue of physical condition preferences for which have previously been suggested to be highly similar across cultures, can vary as a function of cultural factors (Chapter 4). Together, these results indicate that, although aspects of physical condition may be reflected in facial appearance, responses to facial cues are not necessarily universal.

The late positive potential (LPP) is an event-related potential (ERP) component associated with increased affective processing. Studies have shown that stimuli with high evolutionary significance (e.g. a threatening face) induce increased activity over centro-parietal areas of the brain. In an electrophysiological context, this is hypothesized to be indexed by greater LPP amplitudes. The facial width-to-height ratio (fWHR) is a facial-masculinity metric which refers to cheekbone width, divided by upper facial height (top of the lip to between the brows). For the first time, LPP amplitudes were examined in subjects upon observing faces with high vs. low facial fWHRs. Prior studies suggest that faces with high fWHRs are perceived as more threatening than faces with low fWHRs. Consequently, fWHR has by some researchers been proposed to serve as a cue of threat. Two separate tasks in the present study were used to investigate this. In the aggression task, males with high fWHRs were judged as more aggressive. Moreover, when put in a threatening context, high fWHR faces also elicited greater LPP amplitudes in subjects compared to faces with low fWHRs. Conversely, in the self-regulation task, differences in LPP amplitudes did not reach significance. In this task, statistical power was low due to few blocks/trials in the ERP experiment and subjects were not primed on threat, which may explain the non-significant results. Taken together, the results provide modest support to the theory that fWHR serve as a cue of threat. Future studies will need to take the present study’s limitations into consideration

Gli esseri umani sono ipersensibili a quelle proprietà facciali che trasmettono segnali sociali. La capacità di attribuire giudizi di affidabilità basati sui segnali del volto, vale a dire quei segnali che usiamo per dedurre se una persona può essere avvicinata in modo sicuro o piuttosto evitata, è nota per essere veloce, automatica e basata su pochissime informazioni. Questa tesi di dottorato mira a indagare: (1) se la sensibilità ai tratti di affidabilità del volto sia modulata da differenze individuali nelle attitudini sociali e comportamentali; (2) la traiettoria evolutiva di questa sensibilità; (3) se la sensibilità alle sottili variazioni degli indizi facciali all'affidabilità è un fenomeno universale o è piuttosto modulata dalla cultura e / o dall'etnia del viso. Il Capitolo 1 mira a indagare se differenze nella sensibilità percettiva e nella rappresentazione mentale di volti che variano per livello di affidabilità espressa sono associate a differenze individuali relative alla motivazione sociale. I risultati hanno mostrato che le differenze individuali nella motivazione sociale possono avere un impatto sulla quantità di esperienza sociale e quindi sul livello di sensibilità nei confronti di segnali facciali all'affidabilità. Il capitolo 2 si è concentrato sulla traiettoria evolutiva di tale sensibilità. Lo studio 2 mira a studiare in che modo la sensibilità percettiva e la rappresentazione mentale di differenze minime nell'informazione facciale che sottende la percezione di affidabilità si sviluppano nel tempo, tenendo conto delle differenze individuali nello sviluppo emotivo. I risultati hanno mostrato che la sensibilità ai segnali di affidabilità del volto e la capacità di impiegare questi segnali per generare giudizi di affidabilità è presente in età prescolare, ma matura per raggiungere livelli simili a quelli degli adulti all'età di 7 anni, sviluppandosi insieme alle capacità di comprensione delle emozioni. Gli studi 3 e 4 hanno utilizzato due diversi paradigmi EEG con neonati di 6 mesi per indagare se questa sensibilità sia già presente nel primo anno di vita. I dati combinati provenienti dagli studi 3 e 4 contribuiscono a dimostrare che i bambini di 6 mesi sono sensibili a quegli indizi facciali che vengono successivamente utilizzati per generare giudizi di affidabilità. Infine, il capitolo 3 presenta una convalida di stimoli che verranno utilizzati per esplorare la presenza di differenze cross-culturali nello sviluppo nella percezione dell'affidabilità del volto. Nel complesso, tutti gli studi presentati suggeriscono che la sensibilità ai tratti di affidabilità del volto si manifesta nei primissimi anni di vita, per poi affinarsi tramite l'esperienza nel corso dello sviluppo. Inoltre, suggeriscono che la percezione dell’affidabilità di un volto potrebbe essere cross-culturale, in quanto non è influenzata dall'esperienza che un individuo acquisisce con una determinata categoria di volti.
Human beings are hypersensitive to those facial properties that convey social signals. The ability to attribute trustworthiness judgements based on facial cues to trustworthiness, i.e. those cues that we use to derive whether a person can be safely approached or better avoided, is known to be fast, automatic and based on very little information. This doctoral dissertation aims at investigating: (1) whether sensitivity to facial cues to trustworthiness is modulated by individual variations in social personality characteristics; (2) the developmental trajectory of this sensitivity; (3) if sensitivity to subtle variations in facial cues to trustworthiness is a universal phenomenon or is it modulated by culture and/or face ethnicity. Chapter 1 aimed at investigating whether individual differences in fine-grained perceptual sensitivity and mental representation of facial features related to trustworthiness judgements are associated with individual differences in social motivation. Results showed that individual differences in social motivation can have an impact on the amount of social experience and thus the level of developed sensitivity to facial cues to trustworthiness. Chapter 2 focused on the developmental trajectory of such sensitivity. Study 2 aimed to investigate how perceptual sensitivity to and mental representation of fine-grained differences in facial information subtending social perception of trustworthiness develops in time, taking into account individual differences in emotional development. Results showed that sensitivity to facial cues to trustworthiness and the ability to employ these cues to generate trustworthiness judgements is present in preschool years, but matures to reach adult-like levels at the age of 7, developing together with emotion understanding abilities. Study 3 and 4 used two different EEG paradigms with 6-month-old infants to question whether this sensitivity is already present in the first year of life. Combined data coming from Study 3 and 4 contribute in showing that 6-month-old infants are sensitive to those facial cues that are later used to generate trustworthiness judgements. Finally, Chapter 3 presents a validation of stimuli that will be used to explore the presence of developmental cross-cultural differences in the perception of face trustworthiness. Overall, all presented studies suggest that sensitivity to facial cues to trustworthiness manifests in the very first years of life, to be then refined by experience over the course of development. Moreover, they suggest that trustworthiness perception could be cross-cultural, as it is not influenced by the experience an individual gains with a certain face category.

Asperger's syndrome (AS) is a pervasive developmental disorder that is associated with marked social dysfunction. Deficits in the perception of nonverbal cues of emotion may be related to this social impairment. Research has indicated that children with autism are limited in their emotion perception abilities, but studies that have addressed this issue with individuals with AS or high-functioning autism (HFA) have yielded inconsistent findings. These inconsistencies may be related to methodological differences across studies including diagnostic criteria and failure to consider the intensity of the emotion cues. It was hypothesized that children with AS and HFA would both have deficits in emotion perception compared to typically-developing children. However, children with HFA were expected to have an even greater emotion perception deficit than children with AS and this difference was hypothesized to be most pronounced for low intensity cues of emotion. It is important to clarify whether individuals with AS and HFA differ in emotion perception because most studies of this skill combine them into one group or use poorly defined diagnostic criteria. This study examined the ability of 30 8- to 15-year-old children with either AS or HFA to perceive emotion from high and low intensity cues. In order to address limitations with the differential validity of the DSM-IV criteria for AS, diagnoses were based on diagnostic criteria proposed by Klin et al. (in press). A researcher who was blind to diagnosis administered a test that presented low and high intensity cues of emotion in photographs of facial expression and audiotapes of tone of voice. Comparison of the emotion perception accuracy of children with AS to the normative means of this instrument for typically-developing children did not reveal any significant differences. In contrast, the children with HFA were significantly less accurate in their perception of facial expressions and tone of voice than the normative sample and the participants with AS. Contrary to expectations, IQ was significantly related to emotion perception accuracy. After controlling for IQ, the difference in perception of facial expressions between children with AS and HFA was not significant. On the other hand, cue intensity moderated the relation between diagnosis and emotion perception accuracy for tone of voice even after IQ was taken into account. Children with AS perceived high and low intensity tone of voice cues with similar accuracy, but children with HFA had significantly poorer performance on the low intensity tone of voice cues. Although emotion perception accuracy was related to better adjustment, it was not correlated with the most sensitive measure of current social functioning. This suggests that even when children with AS or HFA perceive cues correctly, they may not know how or be able to properly integrate them for adaptive responses in social interaction. The findings have important implications for understanding inconsistencies in past research and identifying future directions.

The recognition of another's emotion is a vital component of social interaction, and a number of brain regions have been implicated in this process. This thesis describes a series of experiments which investigate further the neural basis of emotion recognition, and its disruption in autism, a disorder characterised by profound impairments in social and emotional understanding. First, I attempted to determine more precisely the role of two brain regions, the amygdala and fusiform gyrus, using multivariate analysis to investigate whether the identity of observed emotions is represented in the spatial pattern of activity in these regions. I next focused on a particular cue to emotion - that of social movement. For this purpose, I designed a novel test of emotion recognition using abstract animations. I used this in an fMRI study together with emotion recognition tasks relying on facial expression and prosody. I found that some brain regions involved in processing these more commonly studied cues were also recruited in emotion recognition from the animations. The final studies described here are concerned with emotion recognition in autism. I administered the social movement-based test of emotion recognition to adults with autism and found a deficit in sadness recognition, which extended to the recognition of sadness from facial expressions. Finally, I investigated the impact on emotion recognition of expertise with sensory cues, returning again to the processing of facial expressions. I employed a more subtle test of emotion processing, a posed smile discrimination task, and found impaired performance in the autism group and also reduced gaze to the eye region. These findings are discussed in view of current models of emotion recognition, with reference to the role of the amygdala and its interactions with specialised cortical regions, and the impact of early social experience on subsequent social perceptual and social cognitive ability.

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A investigação da face humana é comum em análise de padrões/ processamento de imagens. Abordagens tradicionais são a identificação e a verificação mas muitas outras estão surgindo, como estimativa de idade, análise de similaridade, atratividade e o reconhecimento de parentesco. Apesar deste último possuir diversas possíveis aplicações, poucos trabalhos foram apresentados até então. Esta tese apresenta um algoritmo apto a discriminar entre irmãos e não irmãos, baseado nas imagens das suas faces. Um grande desafio foi lidar com a falta de um benchmark em análise de parentesco e, por esta razão, uma base de imagens de alta qualidade de pares de irmãos foi coletada. Isto é uma contribuição relevante à comunidade científica e foi particularmente útil para evitar possíveis problemas devido a imagens de baixa qualidade e condições não-controladas de aquisição de bases de dados heterogêneas usadas em outros trabalhos. Baseado nessas imagens, vários classificadores foram construídos usando técnicas baseadas na extração de características e holística para investigar quais variáveis são mais eficientes para distinguir parentes. As características foram primeiramente testadas individualmente e então as informações mais significantes da face foram fornecidas a um algoritmo único. O classificador de irmãos superou a performance de humanos que avaliaram a mesma base de dados. Adicionalmente, a boa capacidade de distinção do algorimo foi testado aplicando-o a uma base de dados de baixa qualidade coletada da Internet. O conhecimento obtido da análise de irmãos levou ao desenvolvimento de um algoritmo similar capaz de distinguir pares pai-filho de indivíduos não relacionados. Os resultados obtidos possuem impactos na recuperação e anotação automática de bases de dados, ciência forense, pesquisa genealógica e na busca de familiares perdidos.----------------------------------------------------------------------------------------------- The investigation of human face images is ubiquitous in pattern analysis/ image processing research. Traditional approaches are related to face identification and verification but, several other areas are emerging, like age/ expression estimation, analysis of facial similarity and attractiveness and automatic kinship recognition. Despite the fact that the latter could have applications in fields such as image retrieval and annotation, little work in this area has been presented so far. This thesis presents an algorithm able to discriminate between siblings and unrelated individuals, based on their face images. In this context, a great challenge was to deal with the lack of a benchmark in kinship analysis, and for this reason, a high-quality dataset of images of siblings’ pairs was collected. This is a relevant contribution to the research community and is particularly useful to avoid potential problems due to low quality pictures and uncontrolled imaging conditions of heterogeneous datasets used in previous researches. The database includes frontal, profile, expressionless and smiling faces of siblings pairs. Based on these images, various classifiers were constructed using feature-based and holistic techniques to investigate which data are more effective for discriminating siblings from non-siblings. The features were first tested individually and then the most significant face data were supplied to a unique algorithm. The siblings classifier has been found to outperform human raters on all datasets. Also, the good discrimination capabilities of the algorithm is tested by applying the classifiers to a low quality database of images collected from the Internet in a cross-database experiment. The knowledge acquired from the analysis of siblings fostered a similar algorithm able to discriminating parent-child pairs from unrelated individuals. The results obtained in this thesis have impact in image retrieval and annotation, forensics, genealogical research and finding missing family members.

Thesis Summary This thesis comprises of seven experimental chapters which demonstrate the ability for naïve observers to accurately distinguish between facial stimuli of individuals scoring high on measures of neuropsychiatric disorders such as depression, borderline and schizotypal personality disorders and autistic spectrum disorder. In the case of depression this ability was still apparent even when the stimuli was reduced to show just the eye and brow region. The findings that observers are able to accurately discriminate between this stimuli furthers the vast literature of face research, demonstrating that this simple stimuli can be used to discriminate traits previously only assessed using thin-slice video stimuli. In addition to this within each study observers were asked to make inferences about socially desirable personality traits, assessed using the big five personality traits. A consistent, negative, personality-type was attributed to individuals with high symptoms levels - commonly consisting of high levels of Neuroticism combined with low levels of Agreeableness and Extraversion. This downgrading of desirable personality traits for individuals scoring highly for neuropsychiatric traits has potential social implications for individuals with these disorders. The traits these individuals are seen to be lower in have been shown to be important in the development and maintenance of successful social relationships, thus if individuals with neuropsychiatric disorders are perceived to be lower in these traits there is the potential that they are at a disadvantage during social interactions. The final section of the thesis looks to link these findings to existing theories of neuropsychiatric disorders. Results demonstrate a masculine facial appearance associated with males with symptoms of autism, supporting Baron-Cohen’s (2002) masculinity hypothesis, and findings that individuals with eating disorders and depression are perceived to be more feminine lend support to Badcock and Crespi’s (2008) diametric hypothesis. These studies highlight a perceptual continuum of gender underlying observations of individuals with neuropsychiatric disorders, where autism lies at the masculine end with attributions of positive personality traits and psychotic disorders are at the feminine end with attributions of negative personality traits. These findings can be associated with Todorov, Said, Engell and Oosterhof’s (2008) theory that perceptions of facial stimuli lie on a two dimensional continuum of trustworthiness and dominance (including assumptions of masculinity). This suggests that perceptions of neuropsychiatric disorders may be attributable to an underlying continuum of social desirability, reflecting the findings of a downgrading of personality traits to high scoring individuals. This thesis extends current facial research, demonstrating that a number of common neuropsychiatric disorders can be distinguished from very simple facial stimuli. Not only this, but a distinct pattern of negative personality traits are attributed to individuals with high levels of neuropsychiatric traits. These combined with the perceptions of gender and the stereotypes associated with these perceptions have potential implications for social interaction. That is, if individuals with neuropsychiatric traits are perceived to have personality traits correlated with negative social connotations, others may be less likely to interact with them, reinforcing some of the symptoms of these disorders.

Previous research suggests that facial characteristics associated with body mass index (BMI) play an important role in health and attractiveness judgments of faces. However, very little work has investigated the factors that predict individual differences in preferences for facial cues of adiposity or how these individual differences are related to social outcomes. In light of the above, the first two empirical chapters of this thesis investigated the relationships between individual differences in preferences for facial cues of adiposity and (1) the BMI of men’s and women’s actual romantic partners and (2) disgust sensitivity. Analyses suggested that people with particularly strong preferences for slim-looking faces were more likely to have partners with low BMI and that men, but not women, who scored higher on pathogen disgust showed stronger aversions to faces displaying cues associated with high BMI. The third chapter investigated how people integrate information from shape cues of adiposity and information from skin color when judging the health and attractiveness of faces. Analyses showed that preferences for cues of low BMI were particularly strong when assessing faces displaying skin color cues associated with the absence of illness. These results suggest that integrating information from shape cues of adiposity and information from skin color could allow people to distinguish between individuals with low BMI because they are healthy and those with low BMI due to illness. Most research investigating the role of facial cues of adiposity in social perception has focused on the possible role of facial adiposity as a health cue. However, it is also possible that facial cues of adiposity contain other types of information, such as information about a person’s reported sociosexual orientation (openness to short-term, uncommitted sexual relationships). To explore this issue, the fourth empirical chapter of my thesis investigated the relationship between facial correlates of BMI and women’s sociosexual orientation. Although analyses suggested that slimmer women reported greater openness to short-term, uncommitted sexual relationships, the observed relationships were weak and, thus, unlikely to play an important role in social interactions. Together these studies support the claim that responses to facial cues of adiposity are related to romantic partner choice and function to distinguish between healthy and unhealthy individuals.

Facial attractiveness plays a crucial role in human mate choice, with individuals from both sexes using facial attractiveness cues to some degree when choosing a partner. Although some of the general facial attractiveness preferences have been studied in cross-cultural populations, most of the research focused specifically on Western populations. Most previous studies also approached facial attractiveness solely from a psychological point of view. One notable exception was a recent study by Roberts et al. (2005) in which the authors linked the Human Leococyte Antigen (HLA) system to cues for health and facial attractiveness in males. This study provides fascinating evidence that genes involved in the immune response also signal attractiveness and health. But is this true cross-culturally and across genders? Roberts et al. (2005) used a British population, who compared to other populations worldwide, have relatively few pathogens that routinely challenge their immune response. The first objective of our study was to test the role of the HLA system in an African female population with a high pathogen load. We found that common HLA alleles, that seemingly provide resistance against common pathogens, play a more important role in health measures than heterozygosity per se. However, our results showed these individuals were not necessarily rated more attractive. So which facial cues do individuals from our study population find attractive in the opposite sex? According to this study individuals from both sexes prefer neotenous features in the opposite sex. Interestingly, we found no preference for facial symmetry and only a slight preference for femininity in females. Our findings support the hypothesis by Boothroyd et al. (2005) that preference for femininity is a by-product of preference for neotenous cues. To test if ethnic preference could not play a confounding role in facial attractiveness ratings of the ethnically mixed South African population, we tested ethnic recognition in two abundant South African ethnic groups. Our results showed that individuals from both sexes could not reliably assign ethnicity to facial images of the two groups. Ethnic preference could therefore not play a role in our study. But mate choice does not only depend on cues displayed by the person being observed. Conditional dependent factors, inherent to the observer, influence how choosy they are of potential partners and therefore how attractive they rate members of the opposite sex. We tested the role of three condition dependent factors, age self-perceived attractiveness and relationship status in both sexes. We observed no significant difference in choosiness between males and females. Male choice therefore plays a more important role in human mate choice than previously expected. Furthermore, our study showed that condition dependent factors affect choosiness differently in males and females. Females are generally more sensitive to condition dependent factors, especially self-perceived attractiveness, while males showed no correlation between any of the condition-dependent factors and choosiness. Since HIV is so prevalent in the South African population, we also tested the role of self esteem in predicting sexual risky behaviour. Our results showed that high self-esteem males were more likely to be sexually active after the age of 18, but that males with low self-esteem were more likely to start sexual activity prematurely. We observed no significant correlation for females. These results indicate that HIV prevention campaigns should focus more on behavioural outcomes other than abstinence, instead of challenging the cultural norms, as indicated by the behavior of high self-esteem individuals. In conclusion, this dissertation is based on the first comprehensive study of genetic and conditional cues associated with facial attractiveness and health in an African population. This African population, with its high pathogen load, high diversity and novel cultural background provided many novel findings, which would hopefully contribute to a more universal view of human mate choice.
Dissertation (MSc (Genetics))--University of Pretoria, 2006.
Genetics
unrestricted

Much of what is known about how we process faces comes from research using static stimuli. Thus, the primary goal of the present series of studies was to compare the processing of more naturalistic, dynamic face stimuli to the processing of static face stimuli. A second goal of the present series of studies was to provide insight into the development of attentional mechanisms that underlie perception of faces. Results from the eye-tracking study (Chapter 2) indicated that viewers attended to faces more than to other parts of the static or dynamic social scenes. Importantly, motion cues were associated with a reduction in the number, but an increase in the average duration of fixations on faces. Children showed the largest effects related to the introduction of motion cues, suggesting that they find dynamic faces difficult to process. Then using selective attention tasks (Chapters 3-5), interactions between the processing of facial expression and identity while participants viewed static and dynamic faces were examined. When processing static faces, viewers experienced significant interference from task-irrelevant cues (expression or identity) while processing the relevant cues (identity or expression). Age-related differences in interference effects were not evident (Chapter 3); however, biological sex and perceptual biases did contribute to the levels of interference seen with static faces (Chapters 4-5). During dynamic trials, however, viewers (regardless of age, sex, or perceptual bias) experienced negligible interference from task-irrelevant facial cues. Taken together, these findings stress the importance of using dynamic displays when characterizing typical face processing mechanisms, using the same methods across development, and of considering individual differences when examining various face processing abilities.

In this quasi-experiment, the relations among life history (LH) strategy, facial symmetry, and facial masculinity were studied. Subject LH was self-reported, and the facial symmetry and masculinity of male images were experimentally manipulated. There are two extremes of LH speed: slow and fast. The goal was to determine what female participants find attractive: symmetry, masculinity, or a combination of both. Such traits are used to assess the quality of potential mates. The females found slow LH strategy males as well as the combination of slow LH strategy and masculine features to be more attractive. However, females that were themselves more attractive, based on self-reports, had lower ratings of attractiveness for the males overall. Health of the female participants also impacted their ratings of the males. Healthier females had generally higher ratings for the males. This study also supported the validity of a self-constructed survey (SRIF) to assess participant immunocompetence.

The human face is one of the most significant stimuli we encounter, and carries a wealth of information regarding socially relevant traits. Previous research has begun to demonstrate that the face displays an array of cues or signals to social traits that others are able to detect. Moreover, the use of cosmetics by females can alter perceptions of social traits. In the current thesis, I demonstrate that both facial shape, skin texture, and viewing angle contribute to the accurate detection of personality traits and physical health from the static, neutral face. The right side of the face affords greater accuracy for personality traits than the left, while facial shape and texture contribute differently to different traits. Consistent with previous literature, we find that skin texture is all that is necessaty to accurately perceive health, and that this information is available from anywhere in the face. I further investigate the accurate detection of personality in female faces, and whether the everyday practice of cosmetics application has any effect on this accuracy. Results indicate that cosmetics do not affect perceptions of actual personality traits, but that perceptions are shifted towards the ideal personality of the wearer. Cosmetics have greater effects on perceptions of social traits, rather than accurate detection. I examined sex differences in perceptions of various social traits in faces of females with and without cosmetics, finding that males generally think females appear more socially desirable without cosmetics, while female observers demonstrate an opposite pattern. Expanding upon this, I also illustrate than females wear an excess of cosmetics for optimal perceptions of traits related to attractiveness. Furthermore, I show that perceptions of attractiveness with cosmetics are generally lower for males across all ages. Popular and conventional accounts suggest that cosmetics are used to attract mates, but the evidence presented here suggests they are failing. I provide the first evidence that the use of cosmetics may be miscalibrated towards a false ideal - females may be applying cosmetics for mistaken ideas regarding male preferences, when in fact, males prefer significantly lower amounts of cosmetics than a normal application results in. Surprisingly, we show that this mistaken belief also extends to males themselves, who feel other males are different to themselves. Typical cosmetics application enhances sex differences in facial contrasts. I further investigated sex differences in skin colouration across multiple samples, and demonstrate how an application of cosmetics acts upon these differences, as well as adding desirable colour properties to faces. Overall, the current thesis further expands the body of literature demonstrating that facial skin plays a role in social cognition, and demonstrates the various ways that cosmetics act upon this feature to alter such perceptions.

Les évaluations faciales sont un élément central des comportements sociaux, influençant un large spectre de décisions, allant du choix du romantique au choix politique, mais sont également le sujet de grandes variations individuelles. Dans cette thèse, je propose que l'analyse des différences individuelles dans l'utilisation de différents signaux sociaux, notamment ceux de coopération et de pouvoir, lors des évaluations faciales est un outil prometteur pour l'étude des comportements sociaux ; j'applique cette approche de deux façons. Dans un premier temps, pour examiner l'hypothèse selon laquelle la motivation sociale correspond à une adaptation aux environnements coopératifs. À travers six études, je montre que la motivation sociale est associée à une plus grande importance donnée aux signaux de coopération, confirmant ainsi une prédiction centrale de cette théorie. Dans un second temps, j'étudie les mécanismes cognitifs impliqués dans les choix politiques, en examinant leurs réponses à différents signaux de l'environnement. Dans un premier travail expérimental, je montre que l'expérience précoce de la précarité est associée à une préférence pour les hommes forts. À partir de ces résultats, je développe une théorie originale sur les préférences politiques selon laquelle les choix politiques sont orientés vers les individus perçus comme les plus aptes à réussir en tant qu'individus et non en tant que chefs de groupe. En résumé, tout au long de cette thèse, je présente un nouveau cadre de travail pour l'étude des décisions sociales et je montre comment il permet éclairer les mécanismes cognitifs sous-tendant les comportements sociaux ainsi que leurs bases évolutives
Face evaluations are a crucial component of social behavior, influencing a large range of social decisions from mating to political vote. Face evaluations are also susceptible to substantial individual differences. In this thesis, I propose that individual differences in face evaluations constitute a promising tool to investigate social behavior through the analysis of variations in the weight granted to different social signals, and notably cooperation- and power-related cues. I apply this approach in two ways. First, I examine the hypothesis that social motivation can be construed as an adaptation to highly cooperative environments. Across six studies, I confirm a central prediction of this theory, by revealing that highly socially motivated individuals grant a higher importance to cooperation-related signals. Second, I investigate the cognitive mechanisms underlying political choices by examining their responses to different environmental signals. In a study on leader preferences in children and in adults, I show that early exposure to environmental harshness is associated with a preference for stronger leaders. Building on these results, I then develop an original theory on political choices stating that leader preferences are biased towards the candidates perceived as the most competent for succeeding in the current context, independently of their leadership abilities. To summarize, my thesis puts forward a new framework to investigate social decisions based on individual variations in face evaluations and sheds light on the cognitive processes underlying social behavior as well as their evolutionary bases

The present study examined the impact of posttraumatic stress symptoms (PTSS) on adults’ ability to discriminate between various facial expressions of emotions. Additionally, the study examined whether individuals reporting PTSS exhibited an attentional bias toward threat-related facial expressions of emotions. The research design was a 2 (expression intensity) x 3 (emotional pairing) x 2 (PTSS group) mixed-model factorial design. Participants for the study were 89 undergraduates recruited from psychology courses at Western Kentucky University. Participants completed the Traumatic Stress Schedule to assess for prior exposure to traumatic events. A median split was used to divide the sample into two groups (i.e., low and high PTSS). Additionally, participants also completed a demographics questionnaire, the Impact of Events Scale-Revised, the Center for Epidemiological Studies Depression Scale, and the Depression Anxiety Stress Scales to assess for possible covariates. Then, participants completed the discrimination of facial expressions task and the dot probe position task. Results indicate that individuals experiencing high levels of PTSS have difficulty discriminating between threatening and non-threatening facial expressions of emotions; additionally, these individuals’ difficulty is exacerbated by comorbid levels of anxiety symptoms. Furthermore, results suggests these individuals focus attention on threatening facial expressions while avoiding expressions that may activate memories associated with the prior trauma. These findings have significant clinical implications, as clinicians could focus treatment on correcting these difficulties which should help promote more beneficial social interactions for these individuals experiencing high levels of PTSS. Additionally, these behavioral measures could be used to assess the effectiveness of treatment. Effective treatment should help alleviate these difficulties, which could be measured by improved performance on the discrimination of facial expressions task and the dot probe position task from baseline to post-treatment.

Facial appearance has a strong effect on leadership selection. Ratings of perceived leadership ability from facial images have a pronounced influence on leadership selection in politics, from low-level municipal elections to the federal elections of the most powerful countries in the world. Furthermore, ratings of leadership ability from facial images of business leaders correlate with leadership performance as measured by profits earned. Two elements of facial appearance that have reliable effects of perceived leadership ability are perceived dominance and attractiveness. These cues have been predictive of leadership choices, both experimentally and in the real-world. Chapters 1 and 2 review research on face components that affect perceived dominance and attractiveness. Chapter 3 discusses how perceived dominance and attractiveness influence perception of leadership ability. Two characteristics that affect both perceived dominance and attractiveness are height and weight. Chapters 4-9 present empirical studies on two recently-discovered facial parameters: perceived height (how tall someone appears from their face) and facial adiposity (a reliable proxy of body mass index that influences perceived weight). Chapters 4 and 5 demonstrate that these facial parameters alter facial attractiveness. Chapters 6, 7, and 8 examine how perceived height and facial adiposity influence perceived leadership ability. Chapter 9 examines how perceived height alters leadership perception in war and peace contexts. Chapter 10 summarises the empirical research reported in the thesis and draws conclusions from the findings. Chapter 10 also lists proposals for future research that could further enhance our knowledge of how facial cues to perceived body size influence democratic leadership selection.

La prima impressione è spesso basata su informazioni limitate che sono estratte automaticamente dall’aspetto dei target. Una classe di giudizi particolarmente importante è quella relativa al giudizio di trustworthiness. Data la sua importanza, siamo in grado di formarci un’impressione di trustworthiness già dopo 33ms di esposizione al volto della persona target. Inoltre il giudizio riguardante la trustworthiness si forma più velocemente dei giudizi riguardanti altre dimensioni della percezione sociale (eg. Dominanza, competenza e piacevolezza). In letteratura altri studi mostrano evidenze riguardanti un vantaggio nel ricordo di volti untrustworthy che supera il vantaggio attribuito a volti che variano lungo altre dimensioni di percezione sociale. In aggiunta è stato dimostrato che la trustworthiness di un volto può predire risposte di approccio o evitamento nell’osservatore. Nella maggior parte degli studi che indagano la percezione di trustworthiness i volti vengono presentati per un breve momento sullo schermo del computer e ai partecipanti è chiesto di categorizzarli. Di conseguenza la percezione di trustworthiness estratta dal volto è spesso considerata come una caratteristica che viene elaborata in maniera relativamente indipendente dal contesto. Tuttavia i volti non vengono mai incontrati in assenza di un contesto nella vita di tutti i giorni. Il presente lavoro cerca di estendere la letteratura precedente indagando come informazioni contestuali possano impattare la percezione di trustworthiness estratta dai volti. A tal scopo abbiamo condotto 8 esperimenti e 5 pretest (N = 691) basati sia su misure che rilevano l’outcome della percezione (eg. Giudizi espliciti e categorizzazioni) che su misure sensibili al processo sottostante (eg. Mouse-tracking). I risultati dei singoli esperimenti e una meta-analisi condotta sull’intero set di dati mostrano che le informazioni contestuali collegate alla minacciosità influenzano il giudizio di trustworthiness. Il presente lavoro dimostra la specificità delle informazioni di minaccia e mette in evidenza come l’effetto della minaccia vada ben oltre l’effetto della semplice valenza. Sembra quindi che la presenza nel contesto di informazioni di minaccia promuova la categorizzazione di un volto come untrustworthy. Al contrario le stesse informazioni contestuali di minaccia sembrano interferire con il processo di percezione rendendo la categorizzazione di volti trustowrthy meno fluida. Un altro aspetto che i nostri dati suggeriscono è che l’integrazione tra la trustworthiness e le informazioni di minaccia avvenga ad un profondo livello dell’architettura cognitiva. Tale risultato è in linea con una prospettiva evolutiva ed è ottenuto dimostrando che l’integrazione di informazioni avviene solo quando tali informazioni sono presenti nello stesso sistema percettivo e non quando le informazioni da integrare provengono da sistemi percettivi differenti. Il quadro generale dei nostri risultati rivela la flessibilità della percezione di trustworthiness e come questa possa essere influenzata da informazioni contestuali allo stimolo percepito.
Our impressions of others are often based on limited information that is spontaneously and automatically extracted from their faces. An important class of inferences concerns judgments of trustworthiness. As such, people start discriminating trustworthiness after 33ms of exposure to a face and the detection of trustworthiness in faces is faster than the detection of a variety of other characteristics, including dominance, likeability, and competence. People show a memory advantage for faces varying on trustworthiness compared with those varying on likeability, friendliness, and dominance and facial trustworthiness predicts basic approach/avoidance responses. In the vast majority of studies examining facial trustworthiness, faces are flashed on the computer screen, and categorization of trustworthiness quickly ensues. In other words, evaluation of facial trustworthiness is often thought to be based on facial features and relatively immune to context cues. However, we rarely encounter an isolated facial expression in the real world. The present dissertation aimed at complementing and extending prior research evidence by investigating whether contextual information may impact the perception of facial trustworthiness. We conducted 8 main experiments and 5 pretests (N = 691) combining outcome based measures (i.e., ratings and explicit evaluations) with process-sensitive measures (i.e., mouse tracking). Results of each single experiment and the meta-analysis of the whole experimental data show that contextual threat information influences the evaluation of facial trustworthiness. We showed the specificity of threat information proving that the effects we found goes over and beyond negative information more in general. Thus, contextual threat information promoted the evaluation and categorization of facial untrustworthiness. By contrast, threatening contextual cues disrupted the processing of trustworthy faces. Moreover, our data suggested that such an integration occurs at a low cognitive level, in accordance with an evolutionary perspective, by showing that the integration is possible when information to be integrated lay in the same perceptual system but not when information is stored on different perceptual systems. Taken together, our findings reveal the malleable nature of trustworthiness such that its perception is readily pushed around by scene context.

Previous studies support that the relative width of the upper face (facial width-to-height ratio; fWHR) has evolved to signal threat, but these studies rely greatly on subjective facial ratings and measurements prone to confounds. The present study objectively quantifies threat perception to the magnitude of the observers’ electrophysiological reaction, specifically the event-related potential (ERP) called the late positive potential (LPP), and investigate if brow height and jaw width could have confounded previous fWHR studies. Swedish and international students (N = 30, females = 11, Mage = 24 years, SDage = 2.9) were shown computer-generated neutral faces created with the underlying skeletal morphology varying in brow ridge height, cheekbone width and jaw width. Participants first rated how threatening each face was and then viewed 12 blocks of 64 faces while their electroencephalography (EEG) was recorded. The results supported that the LPP could be used to index threat perception and showed that only brow height significantly affected both facial ratings (p < .001, ɳp2 = .698) and magnitude of the LPP within the 400 to 800 ms latency (p = .02, d = .542). Hence, brow height, not facial width, could explain previous findings. The results contradict the hypothesis that fWHR is an evolved cue of threat and instead support the overgeneralisation hypothesis in that faces with similar features to anger will be perceived as more threatening.

The general aim of the current dissertation is to investigate whether the semi-rigid movement of a face might affect the encoding and the processing of socially relevant information retrievable from faces, such as identity and emotions, in the first year of life. In particular, the research project is aimed, on one hand, at testing whether facial motion promotes the construction of the face representation, which, in turn, might facilitate identity recognition in newborns and categorization of facial expressions in young infants; on the other hand, the current work is aimed at investigating whether infants are able to process facial motion information alone, when other pictorial cues, such as forms, colors, etc. are unavailable. In the first study, I investigated how the movement of a happy facial expression could impact few-day-old infants’ identity recognition. Previous studies have shown that, when newborns have to recognize a face that changed in some characteristics (such as profile view), the recognition of identity is inhibited (e.g., Turati et al., 2008). It has been demonstrated that both rigid and non-rigid facial motion could promote face recognition at birth (Bulf & Turati, 2010; Leo et al., in prep.). Four experiments have been carried out to test whether the beneficial effect of facial motion might be due to a facial representation more robust and less linked to the image stored in newborns’ memory. Results have demonstrated that the benefits fail when the perceptual distance between the memorized face and the face newborns have to recognize increased (Experiment 1). Accordingly, when the perceptual distance is minimized, newborns are able to recognize the same identity despite the subtle changes even when habituated to a static face (Experiment 2). The third study showed that a biologically impossible facial motion hinders newborns’ face recognition (Experiment 3). Finally, when the quantity of pictorial information is equated, the static presentation does not lead to a successful recognition (Experiment 4). Overall, it seems that non-rigid facial motion could promote a face representation less image-constrained, but only in a condition where the degrees of visual discrepancy between the habituated and the test face images have been minimized. The second study investigated whether emotions expressed dynamically might facilitate the ability to categorize facial expressions at 3 months of age. According to the infants’ literature on the perception of static emotional expressions, categorization starts to appear only between 5 and 7 months of age (e.g., deHaan & Nelson, 1998). Findings coming from naturalistic studies of mother-infant interactions (e.g., Nadel et al., 2005), as well as intermodal preference tasks (e.g., Kahana-Kalman & Walker-Andrews, 2001), suggest that infants’ ability to process facial expressions might have been underestimated. In a within-subject design, 3-month-old infants were familiarized to four different identities posing four different intensities of a happy and a fearful expression, presented sequentially in loop in order to convey the dynamic information. Results have shown that 3-month-old infants are able to categorize the emotion of happiness, whereas they do not show this ability when they are familiarized with the emotion of fear. Such difference is likely due to the different degree of familiarity of happy and fear expressions (Malatesta & Havildand, 1982). Thus, the presentation of dynamic emotional expressions enhances infants’ ability to categorize facial expressions. The purpose of the third study was to analyze infants’ ability to process the dynamicity embedded in a face when other pictorial cues are unavailable, as demonstrated in adults (e.g., Bassili, 1978). To this end, point-light displays (Johansson, 1973) of happy and fear expressions were created. In experiment 1, in a habituation procedure, the ability to discriminate between happy and fear only on the basis of motion cues has been investigated in 3-, 6- and 9-month-old infants. Point-light displays of a face were presented both upright and inverted, to test whether infants were able to organize the motion pattern according to a face-schema. Results have shown an inversion effect at all the three age groups, suggesting that infants process the motion patterns as facial motions. Importantly, when habituated to the happy expression, all the three age groups show successful discrimination ability. In contrast, when habituated to the fear PLD, only 3-month-olds show a successful discrimination, whereas 6- and 9-month olds seem to loose such capability. Experiment 2 ruled out the possibility that a spontaneous preference for the fearful face might have affected infants’ looking behavior. These results seem to indicate that the ability to process facial expressions by relying on motion cues follows a developmental trajectory that starts with an early processing of the lower-level facial attributes, in which motion patterns are processed in a face-related way, and then evolves in the capacity to process the higher-level facial attributes, in which face movements are processed as facial expressions. Overall, the results of the present dissertation suggest that, already within the first months of life, the semi-rigid facial motion might promote the processing of the socially relevant information conveyed by faces by means of an enhanced facial representation. Moreover, the current data reveal that infants are able to process facial expressions from facial motion cues alone starting from 6 and 9 months of age.
Il presente lavoro di tesi si propone di indagare come il movimento semi-rigido del volto influenzi la codifica e la elaborazione di alcune informazioni socialmente rilevanti estraibili dal volto stesso, come l'identità e le espressioni emotive, in bambini al di sotto del primo anno di vita. In particolare, l'ipotesi è che il movimento facciale possa promuovere la costruzione di una rappresentazione mentale che, a sua volta, faciliti il riconoscimento degli stimoli in compiti di abituazione e familiarizzazione visiva. Inoltre, è stata analizzata la capacità degli infanti di processare l'informazione cinetica del volto quando altre informazioni pittoriche, come le forme, i colori, ecc., non sono presenti. Nel primo studio è stato indagato come il movimento facciale veicolato dall'espressione facciale di felicità possa influenzare sulla costruzione della rappresentazione del volto in bambini con un massimo di 3 giorni di vita). Precedenti studi alla nascita hanno dimostrato che quando alcune caratteristiche facciali del volto da riconoscere cambiano, la capacità di riconoscimento dell'identità di un volto viene inibita (e.g., Turati et al., 2008). In questi casi, è stato dimostrato come sia il movimento rigido che quello non-rigido del volto facilitino il riconoscimento dell'identità  alla nascita (Bulf & Turati, 2010; Leo et al., in prep.). Attraverso quattro esperimenti, si è voluta verificare l'ipotesi che l'effetto di beneficio del movimento semi-rigido sia legato alla costruzione di una rappresentazione del volto meno legata all'immagine pittorica immagazzinata in memoria. Anzitutto, i dati dimostrano che il movimento facciale non favorisce il riconoscimento quando viene aumentata la distanza percettiva tra il volto memorizzato e quello da riconoscere (Esperimento 1). Coerentemente, quando tale distanza percettiva è minima, i neonati sono in grado di riconoscere lo stesso volto anche in condizioni statiche (Esperimento 2). Il terzo studio mostra che un movimento biologicamente impossibile ostacola il riconoscimento dell'identità alla nascita (Esperimento 3). Infine, è stato dimostrato come le stesse informazioni pittoriche presentate staticamente in sequenza non portano ad alcun beneficio nel riconoscimento (Esperimento 4). Nel complesso, il movimento non-rigido sembra promuovere una rappresentazione del volto resiliente ai cambiamenti, ma soltanto quando la differenza percettiva tra le diverse immagini dello stesso volto è limitata. Il secondo studio ha indagato se l'utilizzo di stimoli facciali emotivi dinamici consenta l'astrazione di caratteristiche comuni permettendo la categorizzazione delle espressioni facciali di felicità e paura già a 3 mesi di vita. La letteratura sulla capacità di categorizzazione negli infanti, infatti, indica che tale abilità si sviluppi soltanto tra i 5 e i 7 mesi di vita (e.g., deHaan & Nelson, 1998). Tuttavia, nella quasi totalità degli studi sono stati utilizzati stimoli statici. Dati provenienti dalle osservazioni naturalistiche delle interazioni madre-bambino (e.g., Nadel et al., 2005), nonché da studi che utilizzano altri paradigmi sperimentali, come preferenze di tipo intermodale (e.g., Kahana-Kalman & Walker-Andrews, 2001), in cui gli stimoli facciali sono dinamici, suggeriscono una sensibilità al tono emotivo delle espressioni facciali (in particolare, quella di felicità) ben più precoce di quella indicata dagli studi di laboratorio. In un disegno within-subjects, bambini di 3 mesi sono stati familiarizzati a 4 differenti identità che mostravano 4 differenti intensità di felicità e paura presentate sequenzialmente in modo da creare una percezione di dinamicità. I risultati hanno mostrato come l'espressione di felicità viene categorizzata già a tre mesi di vita, mentre questo non succede per quella di paura. Tale differenza è riconducibile al diverso grado di familiarità delle due espressioni (Malatesta & Haviland, 1982). Questi risultati supportano l'ipotesi che il movimento facciale promuova l'astrazione di caratteristiche invarianti del volto, facilitando la categorizzazione delle espressioni facciali. Il terzo studio si è proposto di analizzare la capacità di processare la sola informazione cinetica del volto, scorporata dagli altri indici pittorici. A tal fine, sono stati creati stimoli facciali di tipo point-light (Johansson, 1973) raffigurati la dinamicità delle espressioni di felicità e paura. Nell'esperimento 1, tramite abituazione visiva, è stata indagata la capacità di infanti di 3, 6 e 9 mesi di vita di discriminare queste due espressioni facciali sulla base del solo movimento del volto, come precedentemente dimostrato negli adulti (e.g., Bassili, 1978). Gli stimoli sono stati presentati sia dritti che invertiti, al fine di verificare che il movimento fosse processato come un movimento del volto. I risultati hanno mostrato anzitutto un effetto inversione, che indica che l'insieme dei punti in movimento viene organizzato secondo lo schema volto. Inoltre, quando abituati all'espressione di felicità, i bambini di tutte le tre età dimostrano capacità di discriminazione. Al contrario, quando abituati alla paura, solo i bambini di 3 mesi mostrano capacità di discriminazione, mentre a 6 e 9 mesi questa abilità sembra scomparire. L'esperimento 2 ha escluso la possibilità che una preferenza a priori per l'espressione paura possa aver causato questo andamento. I risultati sembrano indicare che la capacità di processare le espressioni facciali sulla sola base cinetica si evolvi secondo una traiettoria di sviluppo che prevede una iniziale elaborazione di attributi del volto 'low-level', in cui i movimenti vengono processati come movimenti del volto, verso una più sofisticata elaborazione di attributi del volto 'high-level', in cui il movimento è processato come espressione facciale. Nel complesso, i dati di questo lavoro di tesi sembrano suggerire che il movimento facciale possa promuovere l'elaborazione delle informazioni sociali trasmissibili dal volto fin dai primi mesi di vita, attraverso un rafforzamento della costruzione di una rappresentazione del volto. Inoltre, i dati hanno mostrato che la capacità di processare le espressioni facciali sulla sola base del movimento emerge tra i 6 e i 9 mesi di vita.

La grande majorité de nos actions et décisions s’élaborent en présence d’autres individus. De nombreux travaux en psychologie sociale attestent de l’existence d’influences sociales sur les comportements observables par autrui. Nos travaux ont pour objectif de déterminer dans quelles mesures des informations sociales influencent également les processus internes de monitoring métacognitif qui accompagnent les actions cognitives et les prises de décisions. Les indices sociaux non-verbaux (tels que des directions de regards et les expressions faciales) constituent une part importante de la communication humaine. Nos études ont ainsi testé si i) les indices sociaux non-verbaux sont intégrés aux processus de monitoring métacognitif rétrospectif (i.e. à l’élaboration de jugement de confiance); ii) des mécanismes de filtrage permettent de moduler l’impact de ces indices sur les jugements de confiance, en fonction de la pertinence des indices iii) la culture des participants (collectiviste versus individualiste) module l’impact de ces indices sur les jugements de confiance. Nos travaux explorent ces questions à travers quatre ensemble d’études comportementales, dont deux explorant également l’électromyographie faciale des participants, et deux explorant les différences interculturelles (en comparant des participants japonais et français). Dans leur ensemble, ces résultats indiquent que des indices sociaux non-verbaux qui confortent les choix des individus augmentent automatiquement le sentiment de confiance des individus en leur choix, alors même que ces indices ne sont pas fiables. Le traitement de ces indices sociaux particuliers, dans le contexte d’élaboration d’un jugement de confiance, semble reposer sur une voie de type heuristique. Les effets sont très similaires chez les participants Japonais et Français, bien que partiellement plus marqués chez les participants Japonais (i.e. dans les cultures collectivistes). Les réactions électromyographiques faciales suscitées par des expressions faciales signifiantes dans le contexte de réalisation de la tâche cognitive refléteraient différents mécanismes en fonction des valeurs culturelles des individus. Nous discutons des implications de nos résultats dans les domaines cliniques et de l’apprentissage
Actions and decisions most often take place in the presence of others. Previous social psychology studies have shown the effects of social information on external and observable behaviors. In this work, we aim to determine to what extent social information also influences the internal metacognitive monitoring processes underlying cognitive actions and decision-making. Non-verbal social cues (such as gaze direction and facial expressions) constitute an important part of human communication. Here, we have tested (i) whether non-verbal social cues are integrated into the processes of retrospective metacognitive monitoring (i.e. into the assessment of confidence-based judgment); (ii) whether filtering mechanisms are used to modulate the impact of these cues on confidence-based judgment, depending on cue relevance; and (iii) whether participants’ culture (collectivist versus individualist) modulates the impact of these cues on confidence-based judgment. Our work explores these issues through four sets of behavioral studies, two of which also exploring facial expressions using electromyography, and two of which exploring intercultural differences (comparing Japanese and French participants). Overall, we observed that non-verbal social cues that reinforce individuals' choices automatically increase their confidence in those choices, even when the cues are unreliable. The processing of these particular social cues (in the context of the assessment of confidence-based judgment) follow a heuristic pathway. The effects are similar among Japanese and French participants, although somewhat more marked among Japanese participants (i.e. the collectivist culture). The electromyographic recordings of significant facial expressions during the cognitive task likely reflect different mechanisms depending on individuals’ cultural values. We discuss our findings in the context of their clinical and learning applications

Ces travaux de thèse portent sur la reconnaissance automatique du stress chez des humains en interaction dans des situations anxiogènes: prise de parole en public, entretiens et jeux sérieux à partir d'indices audio et visuels.Afin de concevoir des modèles de reconnaissance automatique du stress, nous utilisons : des indices audio calculés à partir de la voix des sujets, capturée par un micro cravate; et des indices visuels calculés soit à partir de l'expression faciale des sujets capturés par une webcam, soit à partir de la posture des sujets capturée par une Kinect. Une partie des travaux portent sur la fusion des informations apportées par les différentes modalités.L'expression et la gestion du stress sont influencées à la fois par des différences interpersonnelles (traits de personnalité, expériences passées, milieu culturel) et contextuelles (type de stresseur, enjeux de la situation). Nous évaluons le stress sur différents publics à travers des corpus de données collectés pendant la thèse: un public sociophobe en situation anxiogène, face à une machine et face à des humains; un public non pathologique en simulation d'entretien d'embauche; et un public non pathologique en interaction face à un ordinateur ou face au robot humanoïde Nao. Les comparaisons inter- individus, et inter-corpus révèlent la diversité de l'expression du stress.Une application de ces travaux pourrait être la conception d'outils thérapeutiques pour la maitrise du stress, notamment à destination des populations phobiques.Mots clé : stress, phobie sociale, détection multimodale du stress , indices audio du stress, indices faciaux du stress, indices posturaux du stress, fusion multimodale
This thesis focuses on the automatic recognition of human stress during stress-inducing interactions (public speaking, job interview and serious games), using audio and visual cues.In order to build automatic stress recognition models, we used audio cues computed from subjects' voice captured via a lapel microphone, and visual cues computed either form subjects' facial expressions captured via a webcam, or subjects' posture captured via a Kinect. Part of this work is dedicated to the study of information fusion form those various modalities.Stress expression and coping are influenced both by interpersonal differences (personality traits, past experiences, cultural background) and contextual differences (type of stressor, situation's stakes). We evaluated stress in various populations in data corpora collected during this thesis: social phobics in anxiety-inducing situations in interaction with a machine and with humans; apathologic subjects in a mock job interview; and apathologic subjects interaction with a computer and with the humanoid robot Nao. Inter-individual and inter-corpora comparisons highlight the variability of stress expression.A possible application of this work could be the elaboration of therapeutic software to learn stress coping strategies, particularly for social phobics.Key words: stress, social phobia, multimodal stress detection, stress audio cues, stress facial cues, stress postural cues, multimodal fusion

The general aim of this thesis was to test the effects of paralinguistic (emotional) and prior contextual (topical) cues on perception of poorly specified visual, auditory, and audiovisual speech. The specific purposes were to (1) examine if facially displayed emotions can facilitate speechreading performance; (2) to study the mechanism for such facilitation; (3) to map information-processing factors that are involved in processing of poorly specified speech; and (4) to present a comprehensive conceptual framework for speech perception, with specification of the signal being considered. Experi¬mental and correlational designs were used, and 399 normal-hearing adults participated in seven experiments. The main conclusions are summarised as follows. (a) Speechreading can be facilitated by paralinguistic information as constituted by facial displayed emotions. (b) The facilitatory effect of emitted emotional cues is mediated by their degree of specification in transmission and ambiguity as percepts; and by how distinct the perceived emotions combined with topical cues are as cues for lexical access. (c) The facially displayed emotions affect speech perception by conveying semantic cues; no effect via enhanced articulatory distinctiveness, nor of emotion-related state in the perceiver is needed for facilitation. (d) The combined findings suggest that emotional and topical cues provide constraints for activation spreading in the lexicon. (e) Both bottom-up and top-down factors are associated with perception of poorly specified speech, indicating that variation in information-processing abilities is a crucial factor for perception if there is paucity in sensory input. A conceptual framework for speech perception, comprising specification of the linguistic and paralinguistic information, as well as distinctiveness of primes, is presented. Generalisations of the findings to other forms of paralanguage and language processing are discussed.

Human social status has long been of interest to evolutionary and social psychologists. The question of who gets to control resources and be a leader has garnered a lot of attention from these and other fields, and this thesis examines evidence for there being two different mechanisms of achieving high status, and their correlates. The mechanisms are 1) Dominance: being aggressive, manipulative and forcing others to follow you, and 2) Prestige: possessing qualities which make others freely follow you. Chapter 1 is an introductory chapter in which I explain selection pressures, group formation, and the need for social hierarchies; I then describe the two proposed methods of attaining social status and how facial characteristics can give clues as to an individual’s social status. In Chapter 2, my first experimental chapter, I examined how faces created to appear either high in dominance or high in prestige were judged with respect to those traits as well as personality characteristics. Taking this further, in Chapter 3, I looked at how natural variation in real faces would reflect differences in other- and self-perceived ratings of dominance and prestige. Chapter 4 served to examine whether, given a set of words related to social status, I would find differences in what words were placed into dominant or prestige categories. Findings within these chapters are consistent with dominance and prestige being separable methods of attaining high status, from differences in facial appearance (Chapter 2 and 3), to personality characteristics (Chapter 2), to word usage (Chapter 4). Once I had established that these were two distinct routes to achieving high status, I chose to focus on dominance in Chapter 5 and explored the conceptual relationships between dominance and facial expressions. I found that manipulating perceptions of dominance affected how intense expressions of anger, sadness, and fear were perceived (Chapter 5). As there has been a paucity of research in the area of women’s social status, in Chapter 6, I went on to explore what effects cosmetics use in women would have on their perceived social status. I found differences in how men and women perceived women wearing cosmetics, which again points to a distinction between dominance and prestige. My thesis then presents a broad view of the two different mechanisms for attaining high status. Using new methods not otherwise used in exploring dominance and prestige I was able to explore correlates and indicators, as well as perceptions of both strategies. These findings will allow us to determine who might be capable of attaining social status, which of the two methods they might use, as well as what implicit associations we hold about each. They will also open doors for future research into the two strategies, and even help interpret previous research, as many previous studies simply relate to high status and do not distinguish between dominance and prestige.

Una componente fondamentale della competenza sociale degli esseri umani è l'abilità di estrarre rapidamente e in modo spontaneo i segnali sociali che provengono dal volto, quali per esempio i tratti emotivi e di affidabilità. Il fatto che le risposte a queste configurazioni facciali siano rapide e automatiche suggerisce come esse derivino dalla pressione evolutiva a rilevare segnali di pericolo per aumentare le possibilità di sopravvivenza. Tuttavia, le origini ontogenetiche di queste abilità sociali sono ancora oggetto di dibattito. La presente tesi di dottorato si pone l'obiettivo di indagare la natura dell’informazione visiva che media la discriminazione delle emozioni e/o la percezione dell'affidabilità dai volti utilizzando l'approccio del filtraggio spaziale, ossia la rimozione selettiva di bande di frequenze spaziali contenute nell'immagine. Nello specifico, l’elaborato comprende 5 studi volti a indagare (1) la natura dell'informazione visiva sui cui si basano i giudizi espliciti di affidabilità degli adulti (Studio 1) (2) se la percezione di affidabilità di adulti (Studio 2) e bambini (Studio 3) è generalizzata a volti di un'etnia differente dalla propria e la natura dell'informazione visiva coinvolta, (3) la natura dell'informazione visiva che determina la discriminazione neurale di affidabilità dai volti nei preverbali (Studio 4), e (4) la natura dell'informazione visiva su cui si basa la discriminazione visiva delle emozioni alla nascita (Studio 5a e 5b). I risultati dello Studio 1 mostrano che sebbene sia le informazioni visive globali, veicolate dalle frequenze spaziali basse, che le informazioni visive locali, veicolate dalle frequenze spaziali alte, sono sufficienti per discriminare tra livelli di affidabilità, l'informazione globale gioca un ruolo cruciale. Gli Studi 2 e 3 estendono le considerazioni sulla natura dell'informazione visiva coinvolta nella percezione di affidabilità a volti meno presenti nell'ambiente sociale dell'individuo, volti di un'altra etnia. Dunque, l'obiettivo è indagare se la percezione di affidabilità nei bambini (Studio 3) si basa sulle stesse informazioni visive su cui si basa negli adulti (Studio 2) e se la stessa differisca in base all'etnia del volto. I risultati mostrano che le informazioni visive coinvolte nella percezione di affidabilità dai volti della propria o altrui etnia cambiano in relazione al grado di familiarità del volto durante lo sviluppo. Nello Studio 4, attraverso un nuovo paradigma di registrazione della risposta neurale, la Fast Periodic Visual Stimulation, viene esplorata l'informazione visiva che i bambini di 6 mesi utilizzano per discriminare tra volti affidabili e inaffidabili. I bambini di 6 mesi discriminano tra volti affidabili e non affidabili sulla base di informazioni visive differenti. Le informazioni locali mediano la discriminazione di volti affidabili mentre la discriminazione di volti non affidabili si basa su informazione visiva locale. I risultati vengono discussi alla luce delle eventuali implicazioni per la comprensione dei meccanismi percettivi e neurali coinvolti nella discriminazione di volti a valenza positiva e negativa. Lo Studio 5 ha indagato il ruolo dell'informazione visiva nella percezione delle emozioni alla nascita. I neonati a 2 giorni di vita discriminano tra volti felici e impauriti sia quando rimangono solo le frequenze spaziali alte che quando rimangono solo le frequenze spaziali basse. Tuttavia, i neonati preferiscono i volti felici ai volti impauriti solo quando nell’immagine rimangono le frequenze spaziali alte. Dunque, l'informazione visiva presente nell'immagine modula la salienza dei segnali sociali dai volti fin dalle prime ore di vita. Nel complesso, i risultati suggeriscono che la percezione di affidabilità ed emotiva si basa su una sensibilità adattiva ed evoluzionistica che si raffina nel corso dello sviluppo come risultato dell'esperienza nell'ambiente sociale.
One fundamental component of humans' social competence is the ability to rapidly and spontaneously extrapolate facial cues of emotion and trustworthiness - i.e., whether others are likely to approach us friendly or hostilely. The fast and automatic nature of these responses to facial configurations has led to the claim that they derive from evolutionary pressure to detect signals of potential harm, and distinguish between friends or foes to enhance our chances of survival. However, the ontogenetic origins of these fundamental social skills are still debated. To explore this question, the studies reported in this doctoral dissertation investigated the nature of the visual information driving emotion discrimination and/or trustworthiness perception across the life span using the spatial filtering approach - i.e., the selective removal of portions of the spatial frequencies (SF) information contained in the image. Specifically, this doctoral dissertation includes 5 studies aimed at investigating (1) the nature of the visual information on which adults' explicit judgments of trustworthiness are based (Study 1), (2) whether trustworthiness perception in adults (Study 2) and children (Study 3) generalizes across face-race and/or the nature of the visual information on which trustworthiness judgments are based differs for more versus less familiar face categories, (3) the nature of the visual information that triggers neural discrimination of facial cues to trustworthiness in preverbal infants (Study 4), and (4) the nature of the visual information that mediates visual discrimination of emotional facial expressions at birth (Study 5a and 5b). Results of Study 1 showed that, although both global visual cues, conveyed by low-spatial frequency bands, and local visual cues, conveyed by high-spatial frequency bands, are sufficient to discriminate between levels of trustworthiness, the selective removal of global information negatively impacts trustworthiness perception. Study 2 and 3 extended evidence on the nature of visual information involved in trustworthiness perception to faces underrepresented in the individual's social environment, other-race faces, in adults and preschool and school children. Results showed that in the course of development the visual information involved in own- and other-race trustworthiness perception changes. Study 4 used a newly developed Electroencephalographic (EEG) visual discrimination paradigm, the Fast Periodic Visual Stimulation, to investigate which visual information 6-month-old infants use to discriminate between trustworthy and untrustworthy faces. The infants’ brain discriminated between high-trustworthy and low-trustworthy faces based on different types of visual information. Results are discussed for their implications for the understanding of the perceptual/neural mechanisms involved in early discrimination between positive and negative valence faces. Study 5 explored the role of visual information in emotion perception at birth. 2-days-old newborns discriminate between happy and fearful facial expressions with both high and low spatial frequency information but they prefer happy faces when only high spatial frequencies remain. The visual information present in the image modulates the salience of the facial cues to emotions from the first hours of life. Altogether, the evidence gathered from the current studies adds to the existing literature suggesting that emotion and trustworthiness perception are based on an adaptive and evolutionary sensitivity early in life that is refined over the course of development as a result of the quantity and quality of facial experience in the social environment.

Après sa découverte, les choix relatifs au développement d'un gisement se prennent sur la base de représentations incertaines du champ. En effet, sa caractérisation utilise des modèles numériques spatiaux porteurs de l'incertitude liée à la complexité du milieu souterrain. D'ordinaire, les méthodes de simulations stochastiques, qui génèrent des modèles équiprobables du sous-sol, sont supposées les quantifier. Néanmoins, ces images alternatives du champ renvoient à des tirages au sein d'un modèle probabiliste unique. Elles oublient l'incertitude relative au choix du modèle probabiliste sous-jacent, et tendent à la sous-estimer. Ce travail de recherche vise à améliorer la quantification de cette incertitude. Elle retranscrit la part de doute relative à la compréhension des propriétés du milieu sur les modèles probabilistes, et propose de l'intégrer à ce niveau. Cette thèse précise d'abord la notion d'incertitude en modélisation pétrolière, en particulier sur les modèles géologiques 3D comprenant différents faciès. Leur construction demande au préalable de définir en tout point de l'espace leur probabilité d'existence : c'est le cube de proportions. Généralement, bien que ces probabilités soient peu connues, les méthodes actuelles d'évaluation de l'incertitude sédimentaire les gardent figées. De fait, elles oublient le caractère incertain du scénario géologique et son impact sur le cube de proportions. Deux méthodes stochastiques de simulation ont été développées afin de générer des modèles équiprobables en termes de cubes de proportions. Elles intègrent la variabilité liée aux proportions de faciès, et explorent dans son ensemble un tel domaine d'incertitude. La première reste relativement attachée à la géologie. Elle intègre directement l'incertitude liée aux paramètres qui composent le scénario géologique. Elle décrit sa mise en oeuvre sur les divers paramètres du scénario géologique, qu'ils prennent la forme de signaux aux puits, de cartes ou d'hypothèses plus globales à l'échelle du réservoir. Une démarche de type Monte-Carlo échantillonne les composantes du schéma sédimentaire. Chaque tirage permet de construire un cube de proportions par l'intermédiaire d'un géomodeleur qui intègre de façon plus ou moins explicite les paramètres du scénario géologique. La méthodologie est illustrée et appliquée à un processus inédit de modélisation des dépôts carbonatés en milieu marin. La seconde revêt un caractère plus géostatistique en se concentrant davantage sur le cube de proportions. Elle vise plutôt à réconcilier les différents modèles sédimentaires possibles. Dans le modèle maillé de réservoir, elle estime la loi de distribution des proportions de faciès cellule par cellule - supposées suivrent une loi de Dirichlet, à partir de quelques modèles, construits sur la base de scénarios géologiques distincts. Elle simule alors les proportions de façon séquentielle, maille après maille, en introduisant une corrélation spatiale (variogramme) qui peut être déterministe ou probabiliste. Divers cas pratiques, composés de réservoirs synthétiques ou de champs réels, illustrent et précisent les différentes étapes de la méthode proposée.

La région cranio-faciale est particulièrement vulnérable aux pertes de structures. Sa localisation et sa visibilité font qu'une atteinte entraîne des troubles, aussi bien physiques (alimentation, phonation...) que psychologiques (intégrité de la personne...). Les traitements actuels (régénération osseuse guidée, autogreffe osseuse ou allogreffe) sont particulièrement invasifs et présentent un taux d'échec élevé. Tout cela affecte fortement la qualité de vie du patient. De plus, le coût direct de ces traitements est important pour les systèmes de santé et le patient. Il existe donc un réel besoin de développer des traitements innovants basés sur des approches biomimétiques d'ingénierie tissulaire pour la régénération/réparation osseuse. L'objectif de ce travail est de développer une approche d'ingénierie tissulaire pour la réparation/régénération de tissus osseux cranio-faciaux lésés. Il est basé sur l'utilisation de matrices cellularisées avec des cellules souches mésenchymateuses issues de la pulpe dentaire : les Dental Pulp Stem Cells (DPSCs). De nombreux travaux ont démontré la grande plasticité de ces cellules, qui dérivent initialement de la crête neurale, mais aussi leur rôle trophique dans la réparation de tissus lésés par leur capacité de différenciation ostéogénique et chondrocytaire. Par ailleurs, ces cellules présentent des propriétés pro-angiogéniques supérieures aux cellules mésenchymateuses de la moelle osseuse (MSCs) et l'accès à cette réserve est aisé puisqu'elles peuvent être obtenues à partir de dents extraites. Dans ce contexte, nous avons à ce jour utilisé des matrices denses de collagène contenant des cellules souches pulpaires pour régénérer un tissu osseux crânien après réalisation de défauts critiques. L'objectif est d'induire très précocement une néo-angiogenèse favorisant à court terme la survie des cellules implantées, puis de stimuler leur maintien à long terme au sein du néo-tissu implanté, pour enfin provoquer une ostéoformation. Nous avons, ainsi, pu étudier et valider différents aspects de cette thématique : .1 L'impact positif de l'utilisation de matrices denses de collagène comme support ostéoconducteur, .2 Le suivi à long terme des cellules après implantation in vivo .3 L'impact positif d'un pré-traitement à l'hypoxie sur i/ la survie des cellules après implantation in vivo ii/ la potentialisation de leur apport pour la régénération/réparation osseuse en orientant leur différenciation vers une voie ostéoblastique, .4 L'apport significatif des techniques d'imageries pour le suivi des animaux grâce à la tomographie par émission de positons (utilisation de traceurs spécifiques de la minéralisation au sein des matrices et de la néo-angiogenèse) et au microscanner à rayons X (suivi cinétique de la qualité et de la quantité de matrice osseuse régénérée), .5 La validation et la confirmation de l'ensemble de ces résultats par l'histologie. Ainsi, ces résultats nous ont permis de répondre à l'objectif de travail et de perfectionner certains aspects de la composante cellulaire. Toutefois, il reste nécessaire d'optimiser le biomatériau lui-même. Il est en effet envisageable d'améliorer les matrices de collagène compressées que nous utilisons actuellement, en y intégrant par exemple des céramiques bioactives. En perspective, potentialiser les biomatériaux des matrices et combiner les DPSCs avec un support plus adapté à leur survie et à leur croissance permettrait d'améliorer considérablement la cicatrisation osseuse. Ces dernières années, l'étude des cellules souches a progressé d'approche in vitro vers l'in vivo. Les modèles in vivo établis pour étudier ces cellules dans le domaine cranio-facial ont déjà apporté des renseignements et ce travail s'inscrit dans leur continuité en cherchant à concevoir des stratégies adaptées pour l'utilisation future des DPSCs en ingénierie tissulaire
The craniofacial area is particularly vulnerable to structural loss. Its location and visibility make a loss causes disorders, both physical (food, phonation...) than psychological (integrity of the person...). Current treatments (autografts, allografts or synthetic bone grafts) are particularly invasive and have a high failure rate. All this strongly affects the quality of life of the patient. In addition, the cost of these treatments is significant for the health systems and the patient. Therefore, there is a real need to develop innovative treatments based on biomimetic tissue approaches for bone repair. The purpose of this thesis is to develop a tissue engineering approach for the repair/regeneration of injured cranial-facial bone tissue. It is based on the use of cellularized scaffolds with mesenchymal stem cells derived from the dental pulp: Dental Pulp Stem Cells (DPSCs). Many studies have demonstrated the high plasticity of these cells, which initially derive from the neural crest, but also their trophic ability in the repair of damaged tissues by their osteogenic and chondrocyte differentiation capacity. Moreover, these cells have better's pro-angiogenic properties than mesenchymal cells of the bone marrow (MSCs) and access to this reserve is easy since they can be obtained from extracted teeth. In this context, we have used dense collagen scaffolds seeded with DPSCs to regenerate cranial bone tissue on critical defects model. The objective is to induce a very early neo-angiogenesis for improved short-term survival of implanted cells, then stimulate the long-term maintenance of cells in the implanted neo-tissue, finally to cause osteoformation. We were able to study and validate various aspects of this theme: 1- The positive impact of the use of dense collagen scaffold as osteoconductive support, 2- Long-term follow-up of the cells after implantation in vivo (thanks to the use of a cell line constitutively expressing an intracellular fluorescence protein), 3- The positive impact of a pre-treatment with hypoxia on i/ the survival of the cells after implantation in vivo ii/ their contribution to bone regeneration / repair by orienting their differentiation towards an osteoblastic pathway, 4- The significant contribution of imaging techniques for the monitoring of animals (less sacrifice and longitudinal follow-up...) thanks to positron emission tomography (use of specific tracers of the mineralization within the scaffolds and neo-angiogenesis) and X-ray microscanner (kinetic monitoring of the quality and quantity of regenerated bone matrix) 5- Validation and confirmation of all these results by histology. Thus, these different results allowed us to respond to the working hypothesis and optimize some aspects of the cellular component. However, it remains necessary to optimize the biomaterial itself. It is indeed possible to improve the compressed collagen scaffolds that we currently use, for example by incorporating bioactive ceramics such as bioglasses or hydroxyapatite. In recent years, the study of stem cells has progressed from in vitro to in vivo. The in vivo models established to study these cells in the craniofacial area have already provided valuable information and this work is a continuation of these previous studies by seeking to build on better strategies (right characterization, environment oriented...) for the future use of DPSCs for tissue engineering purposes. In view of this work, potentiating the biomaterials of the scaffolds and combining the DPSCs with a support more adapted to their survival and their growth would considerably improve bone healing, as well as bone regeneration / repair

Research has shown that people often fail to notice changes to visual scenes. This phenomenon is known as change blindness. This study investigated the effect of facial feature transformations on change blindness using change detection tasks involving a person as the object of change. 301 participants viewed a photo-story comprised of a few still frames. In the final frame, a selected facial feature of a character in the story was altered. Four different photo-stories were used, each utilising a different alteration. Questionnaires designed to determine whether the change was detected were administered. Results showed that changes to facial features considered to be more salient produced higher levels of change detection. A flicker test using the same images from the photo-story was administered to a further 75 participants and showed a similar pattern of results. It was concluded that in order to detect change, the changing stimuli have to be both salient and meaningful.

碩士
國立清華大學
統計學研究所
105
Deception is part of human interaction. Even though there is not a specific clue ties to deception, it is believed that certain verbal and nonverbal cues can be observed on liars due to heavy cognitive load needed for deception. In this study, 23 participants, age ranged from 21 to 29, were interviewed to collect a total of 498 truthful and deceptive responses, and then three facial cues were automatically constructed with a public facial landmark detection system for deception detection. The three cues included participants’ facial landmark distance change over neutral state, average facial landmark distance variation over frames and blinking frequency in a response. With a binary dependent variable as truthful and deceptive responses, logistic regression was used to study the relation between facial cues and deception. Result shows that tense behaviors as tightening lips and lower blinking frequency are significantly related to deception.

碩士
國立東華大學
諮商與臨床心理學系
101
Previous studies have reported that face recognition was more dependent on holistic processing than local processing. Nevertheless the research of various domains, behavioral study, eye-tracking technique and cognitive neuroscience, have found that specific features of the face are importantly relevant for conveying emotional information. Most of these evidences were based on overt attention, less on covert attention. Previous studies of covert attention have reported that the 100–175ms interval between cue and target onset could maximize the spatial cueing effect. Thus, in the present study we used psychophysical method to investigate whether the maximal effect of covert spatial cueing of attention on the eye and mouth features could be beneficial for conveying facial emotional information, and whether the advantage of conveying either the positive or negative emotional information could be due to the effect of covert attention cueing on the specific facial features. In experiment 1, we found that the responses to the happy face were benefited from the cueing on the mouth features, and the responses to the angry face were benefited from the cueing on the eye features. In experiment 2, the 450ms interval between cue and target onset subsided the effect of covert spatial cueing in a non-significant way. Our results provide evidence that specific features of the face are importantly relevant for conveying emotional information, also support a relationship of reciprocal modulation between emotional information and perceptual processing.

Yes
Emerging applications in surveillance, the entertainment industry and other human computer interaction applications have motivated the development of real-time facial analysis research covering detection, tracking and recognition. In this paper, the authors present a review of recent facial analysis for real-time applications, by providing an up-to-date review of research efforts in human computing techniques in the visible domain. The main goal is to provide a comprehensive reference source for researchers, regardless of specific research areas, involved in real-time facial analysis. First, the authors undertake a thorough survey and comparison in face detection techniques. In this survey, they discuss some prominent face detection methods presented in the literature. The performance of the techniques is evaluated by using benchmark databases. Subsequently, the authors provide an overview of the state-of-the-art of facial expressions analysis and the importance of psychology inherent in facial expression analysis. During the last decades, facial expressions analysis has slowly evolved into automatic facial expressions analysis due to the popularity of digital media and the maturity of computer vision. Hence, the authors review some existing automatic facial expressions analysis techniques. Finally, the authors provide an exemplar for the development of a facial analysis real-time application and propose a model for facial analysis. This review shows that facial analysis for real-time application involves multi-disciplinary aspects and it is important to take all domains into account when building a reliable system.

碩士
國立臺灣大學
心理學研究所
99
Purpose and method: The purpose of this study was to investigate the interplay of situation manipulation and the congruency of emotion contextual cues and facial expression on recognition of facial expressions in different social anxiety groups. A 2 × 2 × 5 × 2 mixed design with social anxiety group (high vs. low) and situation manipulation (bogus-speech vs. relax) serving as between participants factors, and facial expression category (angry, contempt, disgust, happy, and neutral face) and congruency (congruent vs. incongruent) serving as within participants factors. The dependent variables were accuracy, error rate, and reaction time. A total of 83 participants were divided into high social anxious group (n = 42) and low social anxious group (n = 41) according to their scores on the Fear of Negative Evaluation Scale. To explore the influence of facial expressions, emotional context, and their interplay on recognition accuracy, five facial expressions along with their five correspondent emotional words were used to form congruent and incongruent pairs, respectively. Results and conclusions: There was a significant influence of emotional context; both groups made more mistakes in incongruent pairs than in congruent ones. The interaction of social anxiety groups and congruency implied that low social anxious participants were more prone to be influenced by emotional context than high social anxious participants. While facial expressions and emotional context both played a role in accuracy of facial expression recognition, high social anxious participants were less prone to be influenced by emotional context, which resulted in more precise in recognizing facial expressions. Besides, while situation manipulations did not made the difference significantly on accuracy of facial recognition, the reaction time for bogus-speech group was significantly longer than that in relaxed group under incongruent pairs. As to error rate, the misrecognition prone of contempt was different in the two social anxiety groups. High social anxious participants were more prone to recognize contempt as neutral than disgust, whereas low social anxious participants were prone to recognize contempt either as disgust or as neutral. According to our study, high social anxious participants were less prone to be influenced by emotion context, which indicated that in social conditions, high social anxious individuals might focus on negative social context and ignore other social contexts as well. Besides, high social anxious participants were more prone to recognize contempt as neutral, which might indicate the expectancy of non-threatening social reply. Taken together, when doing psychotherapy for social anxious individuals, the importance of enhancing their breadth of attention in collecting social information and desensitization of negative evaluation are discussed.

碩士
國立嘉義大學
行銷與流通管理研究所
93
Fear appeal is always using in public welfare advertisement. The purpose of this research is trying to find a concept to distinguish fear appeal into low or high. Study had pointed out, for service advertisement, marketing personnel must especially emphasize the factual information in the advertisement. So as to service, if the factual information clue level in the advertisement is different, what is the advertising result produced? This research regards typicality as the criterion distinguished, putting into two parameters, and forms the experiment design among experimenters of 2×2. Author makes four groups of different advertisement altogether, by periodontal disease and fictitious dentist's clinic, and measures the result on its emotion and intention to residents in Chia-Yi city. Otherwise, if experimenters' conscientious health beliefs and self-health care behavior will influence the emotion and intention. Totally, research grants 300 questionnaires, 271 effective questionnaires altogether in this experiment. The result (1) studied has proved that the manipulation of typicality and factual information cue of this research is successful. (2) Emotional responses and content responses that had been proved were effected by fear appeal. (3) The factual information clue level apparent to the emotion and intention is influenced. (4) There is no interaction which from fear appeal and factual information cue the effects the intention. (5)Conscientious health beliefs apparently influences on the whole emotion attitude and intention attitude. (6) Self-health care behavior only apparently influences on the whole emotion attitude, but does not influences on whole intention attitude.

The present dissertation aims to shed light on different mechanisms of socio-emotional feedback in social decision-making situations. The objective is to evaluate emotional facial expressions as feedback stimuli, i.e., responses of interaction partners to certain social decisions. In addition to human faces, artificial emojis are also examined due to their relevance for modern digital communication. Previous research on the influence of emotional feedback suggests that a person's behavior can be effectively reinforced by rewarding stimuli. In the context of this dissertation, the differences in the feedback processing of human photographs and emojis, but also the evaluation of socially expected versus socially unexpected feedback were examined in detail in four studies. In addition to behavioral data, we used the electroencephalogram (EEG) in all studies to investigate neural correlates of social decision-making and emotional feedback. As the central paradigm, all studies were based on a modified ultimatum game. The game is structured as follows: there is a so-called proposer who holds a specific amount of money (e.g., 10 cents) and offers the responder a certain amount (e.g., 3 cents). The responder then decides whether to accept or reject the offer. In the version of the ultimatum game presented here, different types of proposers are introduced. After the participants have accepted or rejected in the role of the responder, the different proposers react to the participant’s decision with specific emotional facial expressions. Different feedback patterns are used for the individual experiments conducted in the course of this dissertation. In the first study, we investigated the influence of emotional feedback on decision-making in the modified version of the ultimatum game. We were able to show that a proposer who responds to the acceptance of an offer with a smiling face achieves more accepted offers overall than a control proposer who responds to both accepted and rejected offers with a neutral facial expression. Consequently, the smile served as a positive reinforcement. Similarly, a sad expression in response to a rejected offer also resulted in higher acceptance rates as compared to the control identity, which could be considered an expression of compassion for that proposer. On a neuronal level, we could show that there are differences between simply looking at negative emotional stimuli (i.e., sad and angry faces) and their appearance as feedback stimuli after rejected offers in the modified ultimatum game. The so-called feedback-related negativity was reduced (i.e., more positive) when negative emotions appeared as feedback from the proposers. We argued that these findings might show that the participants wanted to punish the proposers by rejecting an offer for its unfairness and therefore the negative feedback met their expectations. The altered processing of negative emotional facial expressions in the ultimatum game could therefore indicate that the punishment is interpreted as successful. This includes the expectation that the interaction partner will change his behavior in the future and eventually make fairer offers. In the second study we wanted to show that smiling and sad emojis as feedback stimuli in the modified ultimatum game can also lead to increased acceptance rates. Contrary to our assumptions, this effect could not be observed. At the neural level as well, the findings did not correspond to our assumptions and differed strongly from those of the first study. One finding, however, was that the neural P3 component showed how the use of emojis as feedback stimuli particularly characterizes certain types of proposers. This is supported by the fact that the P3 is increased for the proposer who rewards an acceptance with a smile as well as for the proposer who reacts to rejection with a sad emoji compared to the neutral control proposer. The third study examined the discrepancy between the findings of the first and second study. Accordingly, both humans and emojis representing the different proposers were presented in the ultimatum game. In addition, emojis were selected that showed a higher similarity to known emojis from common messenger services compared to the second study. We were able to replicate that the proposers in the ultimatum game, who reward an acceptance of the offer with a smile, led to an increased acceptance rate compared to the neutral control proposers. This difference is independent of whether the proposers are represented by emojis or human faces. With regard to the neural correlates, we were able to demonstrate that emojis and human faces differ strongly in their neural processing. Emojis showed stronger activation than human faces in the face-processing N170 component, the feedback-related negativity and the P3 component. We concluded that the results of the N170 and feedback-related negativity could indicate a signal for missing social information of emojis compared to faces. The increased P3 amplitude for emojis might imply that emojis appear unexpectedly as reward stimuli in a social decision task compared to human faces. The last study of this project dealt with socially unexpected feedback. In comparison to the first three studies, new proposer identities were implemented. In particular, the focus was on a proposer who reacted to the rejection of an offer unexpectedly with a smile and to the acceptance with a neutral facial expression. According to the results, participants approach this unexpected smile through increased rejection, although it is accompanied by financial loss. In addition, as reported in studies one and three, we were able to show that proposers who respond to the acceptance of an offer with a smiling face and thus meet the expectations of the participants have higher offer acceptance rates than the control proposer. At the neuronal level, especially the feedback from the socially unexpected proposer led to an increased P3 amplitude, which indicates that smiling after rejection is attributed a special subjective importance. The experiments provide new insights into the social influence through emotional feedback and the processing of relevant social cues. Due to the conceptual similarity of the studies, it was possible to differentiate between stable findings and potentially stimulus-dependent deviations, thus creating a well-founded contribution to the current research. Therefore, the novel paradigm presented here, and the knowledge gained from it could also play an important role in the future for clinical questions dealing with limited social competencies
Die vorliegende Dissertation soll verschiedene Mechanismen des sozio-emotionalen Feedbacks in sozialen Entscheidungssituationen beleuchten. Ziel ist es, emotionale Gesichtsausdrücke als Feedbackreize, d.h. Reaktion des Gegenübers auf bestimmte soziale Entscheidungen, zu evaluieren. Neben menschlichen Gesichtern werden auch künstliche Emojis aufgrund ihrer Relevanz für die moderne digitale Kommunikation untersucht. Bisherige Forschungen zum Einfluss von emotionalem Feedback legen nahe, dass das Verhalten einer Person durch belohnende Hinweisreize erfolgreich verstärkt werden kann. Im Rahmen dieser Dissertation wurden daher vier Studien durchgeführt, die die Unterschiede in der Feedback-Verarbeitung von menschlichen Fotos und Emojis, aber auch die Bewertung von sozial erwartetem gegenüber sozial unerwartetem Feedback eingehend untersuchen. Zusätzlich zu den Verhaltensdaten verwendeten wir in allen Studien das Elektroenzephalogramm (EEG), um neuronale Korrelate sozialer Entscheidungen und emotionalen Feedbacks zu untersuchen. Als zentrales Paradigma wurde allen Studien ein modifiziertes Ultimatumspiel zugrunde gelegt. Dieses ist so aufgebaut, dass es einen sogenannten Anbieter gibt, der über einen bestimmten Geldbetrag verfügt (z.B. 10 Cent) und dem Empfänger einen gewissen Anteil davon anbietet (z.B. 3 Cent). Der Empfänger entscheidet daraufhin, ob er das Angebot annehmen oder ablehnen möchte. In der hier verwendeten Version des Ultimatumspiels werden dabei verschiedene Typen von Anbietern eingeführt. Nachdem die Versuchspersonen in der Rolle des Empfängers angenommen oder abgelehnt haben, reagieren die verschiedenen Anbieter mit spezifischen emotionalen Gesichtsausdrücken auf die Entscheidung der Versuchsperson. Für die einzelnen Experimente, die im Rahmen dieser Dissertation durchgeführt wurden, werden unterschiedliche Feedbackmuster angewandt. In der ersten Studie untersuchten wir den Einfluss des emotionalen Feedbacks auf die Entscheidungsfindung in der modifizierten Version des Ultimatumspiels. Wir konnten zeigen, dass im Ultimatumspiel ein Anbieter, der auf die Annahme eines Angebots mit einem lächelnden Gesicht reagiert, insgesamt mehr akzeptierte Angebote erzielt als der Anbieter der Kontrollbedingung, der sowohl auf angenommene als auch auf abgelehnte Angebote mit einem neutralen Gesichtsausdruck reagiert. Folglich wirkte das Lächeln als positive Verstärkung. In ähnlicher Weise führte ein trauriger Gesichtsausdruck als Reaktion auf ein abgelehntes Angebot ebenfalls zu höheren Annahmeraten als die Kontrollperson, was als Ausdruck von Mitgefühl für diesen Anbieter betrachtet werden könnte. Auf neuronaler Ebene konnten wir zeigen, dass es Unterschiede zwischen dem bloßen Betrachten negativer emotionaler Stimuli (d.h. trauriger und wütender Gesichter) und ihrem Auftreten als Feedback-Stimuli nach abgelehnten Angeboten im modifizierten Ultimatumspiel gibt. Die so genannte feedback-related negativity wurde reduziert (d.h. positiver), wenn negative Emotionen als Feedback von den Anbietern auftraten. Wir zogen aus den Ergebnissen den Schluss, dass die Versuchsteilnehmer die Anbieter bestrafen wollten, indem sie ein Angebot wegen seiner Unfairness ablehnten, und dass daher das negative Feedback ihren Erwartungen entsprach. Die veränderte Verarbeitung negativer emotionaler Gesichtsausdrücke im Ultimatumspiel könnte daher darauf hinweisen, dass die Bestrafung als erfolgreich interpretiert wird. Dies schließt die Erwartung ein, dass der Interaktionspartner sein Verhalten in Zukunft ändert und schließlich fairere Angebote machen sollte. In der zweiten Studie war es das Ziel zu zeigen, dass auch lächelnde und traurige Emojis als Feedback-Reize im modifizierten Ultimatumspiel zu erhöhten Annahmeraten führen können. Entgegen unseren Hypothesen konnte dieser Effekt jedoch nicht beobachtet werden. Auch auf der neuronalen Ebene entsprachen die Ergebnisse nicht unseren Annahmen und unterschieden sich stark von denen der ersten Studie. Eine Erkenntnis war jedoch, dass anhand der neuronalen P3-Komponente ersichtlich wurde, dass die Verwendung von Emojis als Feedback-Reize gewisse Typen von Anbietern besonders kennzeichnet. Dies wurde dadurch gezeigt, dass die P3 sowohl für den Anbieter, der eine Annahme mit einem Lächeln belohnt, als auch für den Anbieter, der auf eine Ablehnung mit einem traurigen Emoji reagiert, im Vergleich zum neutralen Kontrollanbieter erhöht ist. Die dritte Studie untersuchte die Diskrepanz zwischen den Ergebnissen der ersten und der zweiten Studie. Dementsprechend wurden sowohl Menschen als auch Emojis, die die Identitäten der Anbieter repräsentieren, im Ultimatumspiel präsentiert. Darüber hinaus wurden Emojis ausgewählt, die eine höhere Ähnlichkeit mit bekannten Emojis aus den üblichen Messenger-Diensten zeigten als in der zweiten Studie. Wir konnten replizieren, dass die Anbieter im Ultimatumspiel, die eine Annahme des Angebots mit einem Lächeln belohnen, zu einer höheren Annahmerate im Vergleich zu den neutralen Kontrollanbietern führen. Dieser Unterschied zeigte sich unabhängig davon, ob die Anbieter durch Emojis oder menschliche Gesichter repräsentiert wurden. In Bezug auf die neuronalen Korrelate konnten wir zeigen, dass sich Emojis und menschliche Gesichter in ihrer neuronalen Verarbeitung stark unterscheiden. Emojis zeigten sowohl in der gesichtsverarbeitenden N170-Komponente als auch in der feedback-related negativity eine stärkere Aktivierung als menschliche Gesichter. Wir schlussfolgerten daraus, dass die Ergebnisse der N170 und feedback-related negativity ein Signal für fehlende soziale Informationen von Emojis im Vergleich zu Gesichtern sein könnten. Die erhöhte P3-Amplitude für Emojis könnte dabei implizieren, dass Emojis im Vergleich zu menschlichen Gesichtern bei einer sozialen Entscheidungsaufgabe unerwartet als Belohnungsreiz erscheinen. Die letzte Studie dieses Projekts beschäftigte sich mit sozial unerwartetem Feedback. Im Vergleich zu den ersten drei Studien wurden neue Anbieteridentitäten implementiert. Im Mittelpunkt stand insbesondere ein Anbieter, der auf die Ablehnung eines Angebots unerwartet mit einem Lächeln und auf die Annahme mit einem neutralen Gesichtsausdruck reagierte. Den Ergebnissen zufolge nähern sich die Teilnehmer diesem unerwarteten Lächeln durch verstärkte Ablehnung an, obwohl es mit einem finanziellen Verlust einhergeht. Darüber hinaus konnten wir, wie in den Studien eins und drei berichtet, zeigen, dass Anbieter, die auf die Annahme eines Angebots mit einem lächelnden Gesicht reagieren und damit die Erwartungen der Teilnehmer erfüllen, höhere Angebotsannahmeraten haben als der Kontrollanbieter. Auf neuronaler Ebene führte insbesondere das Feedback des sozial unerwarteten Anbieters zu einer erhöhten P3-Amplitude, was darauf hinweist, dass dem Lächeln nach der Ablehnung eine besondere subjektive Bedeutung beigemessen wird. In ihrer Gesamtheit liefern die Experimente neue Erkenntnisse über den sozialen Einfluss durch emotionales Feedback und die Verarbeitung relevanter sozialer Signale. Aufgrund der konzeptionellen Ähnlichkeit der Studien ist es möglich, zwischen stabilen Befunden und möglicherweise reizabhängigen Abweichungen zu differenzieren und damit einen fundierten Beitrag zur aktuellen Forschung zu leisten. Das hier vorgestellte neuartige Paradigma und die daraus gewonnenen Erkenntnisse könnten daher in Zukunft auch für klinische Fragestellungen, die sich mit eingeschränkten sozialen Kompetenzen befassen, eine nicht unerhebliche Rolle spielen

碩士
國立嘉義大學
管理研究所
92
Because there are a lot of product messages prevalent in today society, consumer has been become from a message accepter to an active message filter. So, we think if companies want a good advertising effect, they need to make the consumer fully comprehend the benefits and values about the product. Gutman’s(1982) "Means-End Chain" have been proved by Graff(1997) and Zheng(2003) that can be used to measure the consumer subjective product comprehension. So, we try to introduce this model to advertising "Hierarchy of effects", and hope to understand the effect of advertising endorser and factual information cue on the consumer "advertising message comprehension". This study use 4×2 two factorial experimental design. The experimental products are concrete cellular phone and intangible credit card services, and we use collage students being our survey subjects, there are 322 valid samples were collected. The television advertising is our experimental tool, because this advertising form is more close to the reality and contains ecological validity. The control variables are different types of advertising endorser (celebrity / expert / typical consumer / company employee) and different levels of factual information cues (high / low), the mediate variable is consumer product knowledge structure. We hope to prove under the different factor conditions that the knowledge structure different have any significant different on the effect of consumer "advertising message comprehension" (attribute / consequence / value), "attitude toward advertising" and "attitude toward brand". Finally, we will test different types of advertising product (concrete cellular phone / intangible credit card service) on the effect of advertising. The results are as follow： 1. The advertising message comprehension process will start from concrete "attributes" through abstract "consequences" to extremely abstract "values", and this process follows the "Mean-End Chain" hierarchical rule. 2. There really exists hierarchical relationship between "advertising message comprehension" and "advertising affection attitude". Only when consumers have fundamentally attributive advertising message cognitive comprehension, the following attitude and brand toward advertising effects are just can express. 3. There is significant difference at the effect of "advertising message comprehension", "attitude toward advertising" and "attitude toward brand" under different type of advertising endorsers. The typical consumer has the best effectiveness on the cellular phone, and the celebrity has the best effectiveness on the credit card. 4. There is significant difference at the effect of "advertising message comprehension", "attitude toward advertising" and "attitude toward brand" under different level of factual information cues. The effectiveness of high factual information cues is better than the low factual information cues. 5. There exists an interactive effect between different type of advertising endorsers and different levels of factual information cues, but the effect is different with the different types of product. Cellular phone advertising’s interactive effect is more significant than credit card advertising. 6. There is no significant mediate effect during the effect of "advertising message comprehension", "attitude toward advertising "and "attitude toward brand" under different levels of knowledge structure. 7. There is significant difference at the effect of "advertising message comprehension", "attitude toward advertising" and "attitude toward brand" under different types of product (concrete cellular phone / intangible credit card services).

Thesis (M.S.)--University of Wisconsin--Madison, 1985.
Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 85-99).

碩士
國立臺灣大學
國際企業管理組
104
This globalized telecommunication market and rapidly innovated broadband technologies, make the nature of telecommunication industry be more unpredictable and uncontrollable. Standing on the strong competition and information blooming of today, an entrepreneur shall continuously sense and discover the incremental and fundamental changes in business competitions, own corporation positioning and values, and the sensitive market as being a Telco customer premise equipment provider for telecommunication industry. This paper focused on wired broadband CPE industry and studied the proper competitive strategy as the Telco CPE market nature or technologies turning around. By adapting the strategy analysis tools, we reveal and present that the main stream of broadband CPE infrastructure has been migrated to a cost leading market, rather than a technology and service driving market. This migration is not suitable to all types of players to fit in. Furthermore, this paper exposed the necessity of having a concentrated or specialized market segment strategy after evaluating corporate strengths and developing directions. This focus strategy is then capable to push the corporation on the top of the CPE cost-leading wave.

碩士
國立交通大學
材料科學與工程學系所
102
With the particular optoelectronic characteristics and excellent physicochemical properties, ZnO nanocrystals have been applied to extensive fields. However, the large band gap of ZnO (~3.35eV) prohibits it from effective light absorption under sunlight irradiation, which further limits its applicability in relevant photoelectric processes. To render visible light absorption thus becomes an essential task for the further advancement of ZnO. In this work, an environmentally benign antisolvent method has been developed to prepare transition metal ion-doped ZnO nanocrystals. A room-temperature ionic liquid, known as deep eutectic solvent (DES), was used as the solvent to dissolve ZnO powders. Upon the introduction of ZnO-containing DES into a bad solvent which shows no solvation to ZnO (e.g. water), ZnO was precipitated and grown due to the dramatic decrease of solubility. By adding transition metal ions such as Cu2+, Ni2+ and Co2+ in the bad solvent, the growth of ZnO in antisolvent process was accompanied by metal ion doping, resulting in the formation of metal ion-doped ZnO nanocrystals. The thus-obtained metal ion-doped ZnO showed additional absorption band in visible range (400-800 nm), attributable to the doped ions which invoke the interband transitions within the energy gap of ZnO to enable photoresponse to visible light. The doped ions may generate dopant states to trap charge carriers in the charge transfer process, leading to a depressed photoconversion efficiency for ZnO. Photoelectrochemical water splitting experiments showed that the photoactivity of the Cu2+-doped ZnO achieved the highest at the Cu2+ concentration of 2.0 at%, above which the photocatalytic performance was declined as a result of the significant charge carrier trapping at the dopant states. Furthermore, owing to the significant sp-d interaction between Cu2+ and ZnO, the Cu2+-doped ZnO samples exhibited obvious hysteresis loop at 300K with the saturated magnetization increasing with the increase of Cu2+ concentration.

Il lavoro di tesi consiste nel primo commento scientifico a 44 liriche scelte dello Splendido violino verde, la quinta raccolta poetica di Angelo Maria Ripellino (1923-1978), pubblicata nel 1976. L’apparato esegetico di ciascuna poesia è suddiviso in un cappello introduttivo, in cui, accanto all’analisi tematica, sono sciolti i riferimenti eruditi, storici e biografici ed è fornito il prospetto metrico, e nelle note esplicative in calce al testo, riservate all’analisi puntale degli aspetti retorici e linguistici e alla creazione di un tessuto di rimandi intertestuali ed extratestuali. Di particolare interesse ai fini del lavoro è stata l’analisi, mai effettuata prima, della agende manoscritte dell’autore, conservate nel fondo ripelliniano dell’Archivio del Novecento dell’Università La Sapienza di Roma. Queste hanno permesso di indirizzare lo studio sul versante della critica genetica, poiché contengono appunti di liriche e stralci di versi che costituiscono gli unici avantesti superstiti della raccolta. La loro consultazione ha, inoltre, svelato in molti casi l’origine e la natura di alcuni riferimenti culti celati nelle poesie, confermando il profondo legame tra la scrittura poetica e quella saggistica e critica dell’autore. Ampio spazio è stato quindi dedicato all’intertestualità e alla ricerca delle numerose e variegate fonti, che spaziano dalla letteratura italiana medievale, moderna e contemporanea alle letterature straniere. Spicca inoltre la presenza di fonti relative ad altre arti (teatro, cinema, pittura e musica) che rendono particolarmente densa la scrittura lirica ripelliniana. Nel saggio introduttivo si è tentato di raccogliere i risultati dell’analisi puntuale dei testi, facendo emergere le costanti tematiche e stilistiche, con particolare riguardo per la facies linguistica della raccolta, caratterizzata da molteplici prestiti lessicali dalla tradizione letteraria, fusi insieme a lessico tecnico, termini quotidiani e numerosi vocaboli stranieri col raggiungimento di uno stridente espressionismo.

Oggetto del presente lavoro è stata la tematica dei reati a concorso necessario (detti anche plurisoggettivi): una categoria penalistica scarsamente presa in considerazione da parte della dottrina e giurisprudenza più recenti, eppure dai risvolti sistematici di un certo rilievo, in quanto coinvolge profili sia di parte generale che speciale del diritto penale. L’indagine è partita dal piano definitorio e classificatorio: sono state riportate dettagliatamente le diverse tesi dottrinali sviluppatesi sul tema (suddivisibili in due macrocategorie, quella dei sostenitori di una concezione ampia di reato a concorso necessario e quella dei sostenitori di una concezione ristretta dello stesso), nonché le pronunce della Cassazione ritenute maggiormente significative. Un’attenzione particolare è stata dedicata alla delimitazione – in negativo – del campo d’indagine, tracciando le differenze intercorrenti fra i reati a concorso necessario (o plurisoggettivi, a seconda della terminologia impiegata) ed istituti ritenuti erroneamente contigui, primo fra tutti quello del concorso eventuale di persone nel reato. Dopodiché, all’interno del secondo capitolo si è scelto di riflettere sulle questioni maggiormente rilevanti e problematiche attinenti ai reati a concorso necessario impropri: in primis, la ratio che giustifica l’esenzione dalla pena in capo ad un soggetto; secondariamente, la possibilità di punire o meno la condotta tipica, nonché le eventuali condotte atipiche, poste in essere dal soggetto non punibile per mezzo dell’applicazione degli artt. 110 ss. c.p. in funzione incriminatrice. La panoramica di orientamenti dottrinali e giurisprudenziali quanto mai oscillanti e fra loro divergenti su questioni di particolare importanza, non è stata solo funzionale ad offrire al lettore una dettagliata ricognizione in generale, piuttosto, da questa è scaturita una vera e propria esigenza di (ri)considerare l’intera materia in modo organico e chiarificatore. Per tale ragione, nel terzo capitolo è stata introdotta una nuova definizione, in sostituzione a quella maggiormente impiegata da dottrina e giurisprudenza: “fattispecie incriminatrici normativamente plurisoggettive”. Una definizione idonea a ricomprendere tutti quegli illeciti penali che, a livello astratto, presentano caratteristiche simili: il riscontro di una pluralità di soggetti e di condotte quali elementi costitutivi del fatto tipico. Pertanto, si è cercato di individuare i confini della categoria assumendo quale criterio di partenza il piano normativo astratto, in considerazione del fatto che ciò che il legislatore ha scelto di codificare come tipo criminoso è dato dall’insieme degli elementi oggettivi e soggettivi, i quali compaiono nella descrizione della norma incriminatrice. La visione d’insieme ha permesso di non limitare l’attenzione al solo soggetto punibile, bensì di spostarla anche sul soggetto non punibile, il quale, con la sua condotta rientrante fra gli elementi oggettivi del fatto tipico, contribuisce alla configurabilità del reato. Infine, all’interno del quarto capitolo si è proceduto all’analisi dei principali reati classificati da parte della dottrina come a concorso necessario impropri, per verificare, tenuto conto della nuova definizione proposta, se possano o meno essere qualificati come fattispecie incriminatrici normativamente plurisoggettive improprie. Il confronto con la parte speciale ha permesso di evidenziare l’estrema delicatezza dell’operazione d’individuazione di fattispecie incriminatrici normativamente plurisoggettive (in senso lato): anzitutto, perché non sempre la pluralità di soggetti e di condotte costitutive del fatto tipico è oggetto di descrizione espressa, risultando alle volte ricavabile solo a seguito di un attento esame della tipologia e del significato delle parole impiegate dal legislatore; secondariamente, perché alle volte è facile lasciarsi confondere dal piano naturalistico della realtà concreta, mentre l’individuazione di una fattispecie incriminatrice in termini di plurisoggettività normativa dovrebbe avvenire, secondo l’impostazione adottata, a partire dal piano normativo astratto. Da ultimo, ci si è soffermati sul ruolo del soggetto non punibile che tenga rispettivamente la condotta tipica o una condotta ulteriore e diversa da quella descritta, cercando di offrire una possibile soluzione al problema. Nel primo caso, si è concluso per l’impossibilità di applicare l’art. 110 c.p. in funzione incriminatrice, pena la violazione delle garanzie proprie del sistema penalistico. Nel secondo, invece, si è concluso in senso affermativo, precisando che l’interprete è tenuto a prestare attenzione a diversi aspetti, fra cui il tipo d’equilibrio intercorrente fra le condotte dei soggetti parte della fattispecie incriminatrice normativamente plurisoggettiva impropria, nonché l’alterità effettiva della condotta atipica rispetto a quella descritta, pena la violazione dei principi di legalità, tipicità e certezza del diritto.

Food safety is a key objective in all the development plans of the European Union. To ensure the quality and the sustainability of the agricultural production (both intensive and extensive) a well-designed analysis strategy is needed. Climate change, precision agriculture, green revolution and industry 4.0 are areas of study that need innovative practices and approaches that aren’t possible without precise and constant process monitoring. The need for product quality assessment during the whole supply chain is paramount and cost reduction is also another constant need. Non targeted Nuclear Magnetic Resonance (NMR) analysis is still a second-choice approach for food analysis and monitoring, one of the problems of this approach is the big amount of information returned. This kind of data needs a new and improved method of handling and analysis. Classical chemometrics practices are not well suited for this new field of study. In this thesis, we approached the problem of food fingerprinting and discrimination by the means of non-targeted NMR spectroscopy combined with modern machine learning algorithms and databases meant for the correct and easy access of data. The introduction of machine learning techniques alongside the clear benefits introduces a new layer of complexity regarding the need for trusted data sources for algorithm training and integrity, if this kind of approach proves is worth in the global market, we’ll need not only to create a good dataset, but we’ll need to be prepared to defend against also more clever attacks like adversarial machine learning attacks. Comparing the machine learning results with the classic chemometric approach we’ll highlight the strengths and the weakness of both approaches, and we’ll use them to prepare the framework needed to tackle the challenges of future agricultural productions.