Dissertations / Theses on the topic 'Size illusions'

The influence of color on size and depth perception has been explored for a century, but there is very limited research on interventions that can reduce the color illusions. This study was motivated to identify interventions and propose design guidelines for information visualization, especially where size judgment is critical.

This study replicated the color size illusion and color depth illusion on an LCD monitor and it was found that yellow is the smallest and farthest color among red, yellow, green, and blue on a white background. Three types of interventions (background brightness, border color, and background grid brightness) were tested to identify the conditions that reduce the color illusions, but all of them were not statistically significant.

Based on the experiment results and literature survey, design guidelines were proposed. To extend the guidelines to the bioinformatics field, design recommendations were proposed and implementation examples were illustrated. Evaluations on design implementations were evaluated by interviewing domain experts.

Additionally, the relationship between the color size illusion and the color depth illusion was explored.

Master of Science

L’hypothèse des voies visuelles attribue des rôles fonctionnels spécifiques aux réseaux cérébraux ventral et dorsal du système visuel. Ce modèle émet l’hypothèse selon laquelle la voie ventrale sous-tend le traitement de l'information pour la perception (vision-for-perception), alors que la voie dorsale est impliquée dans le traitement de l'information pour l'action (vision-for-action). L'idée de deux réseaux visuels distincts dans le cerveau humain a fait l’objet de très nombreux travaux de recherche au cours des 20 dernières années, mais les résultats apparaissent contradictoires. Cette thèse vise à éclaircir une partie du mystère de la façon dont la perception et l'action s’articulent. La figure d’Ebbinghaus a été utilisée pour distinguer la fonction d’une vision pour la perception, sensible aux illusions visuelles (taille relative), de la fonction d’une vision pour l’action affectée par les propriétés physiques de l’objet. Dans une première étude, nous avons quantifié l’illusion d’Ebbinghaus. Après, une démarche comparable de caractérisation des mouvements visuomoteurs a été implémentée sous des contraintes de précision et de vitesse. La caractérisation des mouvements visuomoteurs et la quantification de la perception des configurations Ebbinghaus ont ensuite permis de concevoir une tâche visuomotrice dont les cibles étaient des figures d’Ebbinghaus.La thèse a démontré que les voies ventrale et dorsale ne sont pas strictement distinctes fonctionnellement. Différentes variables informationnelles sont potentiellement utilisées pour ‘la vision pour la perception’ et ‘la vision pour l’action’ indépendamment du fait que certaines variables causent des illusions
The influential two-visual streams hypothesis ascribes specific functional roles to the ventral and the dorsal network of the visual system. The ventral system has been hypothesized to process information for conscious perception (vision-for-perception), whereas the dorsal stream processes information for action (vision-for-action). The idea of two separate visual networks in the human brain inspired an enormous amount of research over the past 20 or so years. The results are conflicting and divisive about the idea, causing a seemingly insurmountable gap between supporters and opponents. This thesis aims to unravel a part of the jigsaw puzzle of how perception and action are functioning. The Ebbinghaus figure has been used to distinguish vision-for-perception that is susceptible to visual illusions (i.e., relative size) from vision-for-action that remain unaffected by perceptions of relative sizes. Therefore, we quantified the Ebbinghaus figure based on its geometry and systematically assessed its size illusion. Subsequently, a visuomotor task was implemented in which precision and speed of the voluntary movement were investigated. The description of the visuomotor task and of the perception of Ebbinghaus figures lead to combine both visuomotor task and Ebbinghaus figures. A dynamical model was fit to the experimental data to investigate the effect on the behavioral dynamics.This thesis demonstrated that the ventral stream and dorsal stream are not strictly functionally distinct, and that potentially different informational variables are used for ‘vision for perception’ and ‘vision for action’ irrespective of whether certain variables cause (perceptual) illusions

People are generally quite good at adapting to changes in body shape and size because of the flexibility of the body representation. By means of bodily illusions, it is possible to experimentally induce updating of body representation and, thus, manipulate the sense of self. The main aim of this thesis is to investigate the sense of self through bodily illusions. Firstly, we investigated the relationship between the sense of ownership and self-localisation (Study 1). The results from this study are taken to suggest that the proprioceptive drift (i.e. a bias in the localisation of a given body part) is more likely triggered by and related to the visual capture of touch than it is a reliable measure of a shift in the sense of body ownership. In fact, our data show that the proprioceptive drift occurs not only in the absence of a shift in the sense of ownership, but even in the absence of a body-like object. Secondly, we investigated self-localisation of body parts by means of a novel illusion, the Disappearing Hand Trick. In particular, we explored the role of vision and proprioception (Study 2), as well as the role of attention and motor acts (Study 3), in locating one’s own hands when visual and proprioceptive information regarding the body are incongruent. Our data (Study 2) are in line with previous research, confirming a predominant role of vision over proprioception. In addition, they show that, after a certain amount of time, proprioception is weighted more heavily than vision. That is, our results demonstrate that the cortical proprioceptive representations can be updated even when there is no real need to do it (i.e. no movement is required). This might be seen as an evolutionarily convenient response to keep the body ready for a possible quick reaction. In Study 3, we ruled out the possibility that this effect was only driven by spatial attention being directed towards the side of the space where the hand was actually located. In fact, no difference in the localisation accuracy was found when the direction of spatial attention was manipulated. Finally, by asking the participants to reach across for their hidden right hand (Study 3), we confirmed that a motor act accelerates the reliance on proprioception, most likely by aligning the motor and perceptual coordinates in order to plan the movement. In the first three studies, a modification of the body representation was intentionally induced – namely, the purpose of the illusions was to change how the participants perceived their body. However, we wondered whether this same change might also occur at a more implicit level and how rapidly this may occur. We designed two different studies in which we tried to manipulate the participants’ perceived body size by providing incongruent information about the position of their limb (Study 4) or by showing the participants images of unrealistic bodies (Study 5). In Study 4 we showed that incongruent proprioceptive information coming from the same joint does not affect the perceived size of that body part, but does lead to a more accurate estimation of its position. On the other hand, the results of Study 5 would seem to suggest that body perception is more vulnerable to change in women than in men after exposure to same-sex ideal bodies. Taken together, these results suggest that, by manipulating the body representation, both explicitly, by means of a variety of bodily illusion, and even implicitly, by generating subtle incongruence between one’s own real body and how the body ‘should’ be, we were able to shed some light on the mechanisms behind the computation of body position and size, both of which are important elements for the definition of the self.

La distorsione della percezione della distanza tra due stimoli puntuali applicati sulla superfice della pelle di diverse regioni corporee è conosciuta come Illusione di Weber. Questa illusione è stata osservata, e verificata, in molti esperimenti in cui ai soggetti era chiesto di giudicare la distanza tra due stimoli applicati sulla superficie della pelle di differenti parti corporee. Da tali esperimenti si è dedotto che una stessa distanza tra gli stimoli è giudicata differentemente per diverse regioni corporee. Il concetto secondo cui la distanza sulla pelle è spesso percepita in maniera alterata è ampiamente condiviso, ma i meccanismi neurali che manovrano questa illusione sono, allo stesso tempo, ancora ampiamente sconosciuti. In particolare, non è ancora chiaro come sia interpretata la distanza tra due stimoli puntuali simultanei, e quali aree celebrali siano coinvolte in questa elaborazione. L’illusione di Weber può essere spiegata, in parte, considerando la differenza in termini di densità meccano-recettoriale delle differenti regioni corporee, e l’immagine distorta del nostro corpo che risiede nella Corteccia Primaria Somato-Sensoriale (homunculus). Tuttavia, questi meccanismi sembrano non sufficienti a spiegare il fenomeno osservato: infatti, secondo i risultati derivanti da 100 anni di sperimentazioni, le distorsioni effettive nel giudizio delle distanze sono molto più piccole rispetto alle distorsioni che la Corteccia Primaria suggerisce. In altre parole, l’illusione osservata negli esperimenti tattili è molto più piccola rispetto all’effetto prodotto dalla differente densità recettoriale che affligge le diverse parti del corpo, o dall’estensione corticale. Ciò, ha portato a ipotizzare che la percezione della distanza tattile richieda la presenza di un’ulteriore area celebrale, e di ulteriori meccanismi che operino allo scopo di ridimensionare – almeno parzialmente – le informazioni derivanti dalla corteccia primaria, in modo da mantenere una certa costanza nella percezione della distanza tattile lungo la superfice corporea. E’ stata così proposta la presenza di una sorta di “processo di ridimensionamento”, chiamato “Rescaling Process” che opera per ridurre questa illusione verso una percezione più verosimile. Il verificarsi di questo processo è sostenuto da molti ricercatori in ambito neuro scientifico; in particolare, dal Dr. Matthew Longo, neuro scienziato del Department of Psychological Sciences (Birkbeck University of London), le cui ricerche sulla percezione della distanza tattile e sulla rappresentazione corporea sembrano confermare questa ipotesi. Tuttavia, i meccanismi neurali, e i circuiti che stanno alla base di questo potenziale “Rescaling Process” sono ancora ampiamente sconosciuti. Lo scopo di questa tesi è stato quello di chiarire la possibile organizzazione della rete, e i meccanismi neurali che scatenano l’illusione di Weber e il “Rescaling Process”, usando un modello di rete neurale. La maggior parte del lavoro è stata svolta nel Dipartimento di Scienze Psicologiche della Birkbeck University of London, sotto la supervisione del Dott. M. Longo, il quale ha contribuito principalmente all’interpretazione dei risultati del modello, dando suggerimenti sull’elaborazione dei risultati in modo da ottenere un’informazione più chiara; inoltre egli ha fornito utili direttive per la validazione dei risultati durante l’implementazione di test statistici. Per replicare l’illusione di Weber ed il “Rescaling Proess”, la rete neurale è stata organizzata con due strati principali di neuroni corrispondenti a due differenti aree funzionali corticali: • Primo strato di neuroni (il quale dà il via ad una prima elaborazione degli stimoli esterni): questo strato può essere pensato come parte della Corteccia Primaria Somato-Sensoriale affetta da Magnificazione Corticale (homunculus). • Secondo strato di neuroni (successiva elaborazione delle informazioni provenienti dal primo strato): questo strato può rappresentare un’Area Corticale più elevata coinvolta nell’implementazione del “Rescaling Process”. Le reti neurali sono state costruite includendo connessioni sinaptiche all’interno di ogni strato (Sinapsi Laterali), e connessioni sinaptiche tra i due strati neurali (Sinapsi Feed-Forward), assumendo inoltre che l’attività di ogni neurone dipenda dal suo input attraverso una relazione sigmoidale statica, cosi come da una dinamica del primo ordine. In particolare, usando la struttura appena descritta, sono state implementate due differenti reti neurali, per due differenti regioni corporee (per esempio, Mano e Braccio), caratterizzate da differente risoluzione tattile e differente Magnificazione Corticale, in modo da replicare l’Illusione di Weber ed il “Rescaling Process”. Questi modelli possono aiutare a comprendere il meccanismo dell’illusione di Weber e dare così una possibile spiegazione al “Rescaling Process”. Inoltre, le reti neurali implementate forniscono un valido contributo per la comprensione della strategia adottata dal cervello nell’interpretazione della distanza sulla superficie della pelle. Oltre allo scopo di comprensione, tali modelli potrebbero essere impiegati altresì per formulare predizioni che potranno poi essere verificate in seguito, in vivo, su soggetti reali attraverso esperimenti di percezione tattile. E’ importante sottolineare che i modelli implementati sono da considerarsi prettamente come modelli funzionali e non intendono replicare dettagli fisiologici ed anatomici. I principali risultati ottenuti tramite questi modelli sono la riproduzione del fenomeno della “Weber’s Illusion” per due differenti regioni corporee, Mano e Braccio, come riportato nei tanti articoli riguardanti le illusioni tattili (per esempio “The perception of distance and location for dual tactile pressures” di Barry G. Green). L’illusione di Weber è stata registrata attraverso l’output delle reti neurali, e poi rappresentata graficamente, cercando di spiegare le ragioni di tali risultati.

Cette thèse se propose d’étudier la difficulté de l’estimation de la distance dans le cadre de la géométrie de l’espace visuel. En philosophie de la perception, cette thèse est d'abord discutée au plan épistémologique : comment savoir que cette distance n'est pas connue ou connaissable, quoique perçue et discutée. Les travaux de Berkeley nous servent de point de départ et fixent un cadre spéculatif, puisque Berkeley soutient en effet que le jugement porté sur la distance résulte entièrement de l'expérience, quoique cette distance ne puisse être vue phénoménalement. La thèse se propose d'examiner une question essentielle supportée par cette alternative centrale mais au plan ontologique cette fois : comme déterminer de quel type est la distance : est-elle inconsciemment visible ? tangible ? ou visible et tangible à la fois ? Peut-elle être une entité assignable dans un espace hyperbolique, ou sphérique, un espace strictement euclidien, ou hyperbolique et sphérique en même temps qu'euclidien ? Pour appuyer notre propos et notre recherche nous mettrons à l’épreuve différents textes et expériences en passant de Berkeley à I. Rock ou de T. Reid à M. Wagner. Notre but aura été d'explorer les limites argumentatives et de montrer ce qui est impliqué par ces différentes appréciations et assignations de la distance dans tel ou tel espace déterminé. A chaque fois s'affrontent la géométrie de l’espace visuel et l’optique physiologique, mais au sein d'un même débat de fond qui consiste à savoir comment définir philosophiquement l’estimation de la distance ?
This thesis examines the difficulties in estimating the geometrical distance of visual space. Submitted in the field of Philosophy of Perception, this thesis is first discussed from an epistemological standpoint: how does one know that this distance is unknown or unknowable despite being perceived and discussed. The various works of Berkeley serve as a point of depart and establish a speculative framework as Berkeley held that judgment of distance results entirely from experience despite the fact that this distance cannot be seen in a phenomenal way. This thesis examines an essential question supported by this central problem, this time from an ontological position: how is the type of distance to be determined: is it unconsciously visible?tangible? or both visible and tangible at the same time? Can it be categorized in a hyperbolic space, or spherical space, or a strictly Euclidean space, or hyperbolic and spherical at the same time as Euclidean? In support of the thesis and research, various texts and experiences have been examined and contrasted, including those of Berkeley and I. Rock as well as T. Reid and M. Wagner. The goal has been to explore the limits of argumentation and to show what is implicated by these different accounts and assignment of distance in one, versus another, determined space; additionally studying subjects including the experience of the alleys or the so-called the moon illusion, which appeared to be demonstrative examples. In each instance, geometry of visual space and physiological optics confront one another, but at the center of this same fundamental debate is the question of how to define the estimation of distance philosophically?

Behavioral operations management (BOM) has gained popularity in the last two decades. The main theme in this new stream of research is to include the human behavior in Operations Management (OM) models to increase the effectiveness of such models. BOM is classified into 4 areas: cognitive psychology, social psychology, group dynamics and system dynamics (Bendoly et al. 2010). This dissertation will focus on the first class, namely cognitive psychology. Cognitive psychology is further classified into heuristics and biases. Tversky and Kahneman (1974) discussed 3 heuristics and 13 cognitive biases that usually face decision makers. This dissertation is going to study 6 cognitive biases under the representativeness heuristic. The model in this dissertation states that cognitive reflection of the individual (Frederick 2005) and training about cognitive biases in the form of warning (Kaufmann and Michel 2009) will help decisions’ makers make less biased decisions. The 6 cognitive biases investigated in this dissertation are insensitivity to prior probability, insensitivity to sample size, misconception of chance, insensitivity to predictability, the illusion of validity and misconception of regression. 6 scenarios in OM contexts have been used in this study. Each scenario corresponds to one cognitive bias. Experimental design has been used as the research tool. To see the impact of training, one group of the participants received the scenarios without training and the other group received them with training. The training consists of a brief description of the cognitive bias as well as an example of the cognitive bias. Cognitive reflection is operationalized using cognitive reflection test (CRT). The survey was distributed to students at University of North Texas (UNT). Logistic regression has been employed to analyze data. The research shows that participants show the cognitive biases proposed by Tversky and Kahneman. Moreover, CRT is significant factor to predict the cognitive bias in two scenarios. Finally, providing training in terms of warning helps participants to make more rational decisions in 4 scenarios. This means that although cognitive biases are inherent in the mind of people, management of corporations has the tool to educate its managers and professionals about such biases which helps companies make more rational decisions.

Per costanza di grandezza si intende la capacità del sistema visivo di mantenere costante la percezione delle dimensioni di un oggetto, malgrado le modificazioni dell'immagine retinica con la distanza. In letteratura il rapporto tra grandezza dello stimolo e tempo di reazione (TR) è ben noto: all'aumentare della grandezza i TR diminuiscono. Con il presente progetto si è voluto verificare se questo effetto sui TR dipenda dalla grandezza percepita dagli stimoli oppure dalla grandezza che questi producono sulla retina, manipolando sia la dimensione degli stimoli, sia la distanza stimolo-soggetto. E' stato ottenuto un TR più rapido per gli stimoli più grandi rispetto a quelli più piccoli, anche se presentati a distanze diverse in modo tale da produrre sempre la stessa immagine retinica. Questo effetto può essere attribuito al meccanismo della costanza di grandezza che ha agito sui TR. Per confermare questo dato sono stati condotti ulteriori esperimenti in condizioni di riduzione percettiva, dove il ruolo della costanza di grandezza può essere notevolmente compromesso. Per questo motivo, quando gli indizi necessari alla costanza di grandezza sono stati rimossi attraverso l'utilizzo di uno spioncino per l'osservazione (pinhole), il TR è stato determinato esclusivamente dalle dimensioni dell'immagine retinica. Infine, in altri esperimenti sono state utilizzate illusioni ottiche come quella di Ponzo o di Ebbinghaus per indurre una mispercezione della grandezza. Ancora una volta, stimoli che per effetto dell'illusione sono stati percepiti come più grandi hanno prodotto TR più rapidi, nonostante la grandezza retinica fosse sempre la stessa. In conclusione, tutti questi risultati dimostrano che i TR rispondono alla grandezza percepita dagli stimoli, anzichè quella retinica.
Size constancy is a property of the visual perceptural system that can keep relatively constant the perceived size of an object despite changes of the size of the retinal image with distance. The relationship between size and reaction time (RT) is well known: RT is faster in response to larger than smaller stimuli. Here i Wanted to verify whether this effect depends upon retinal or perceived size, by changing both stimulus size and the observer-object distance. I found that when the size of stimuli positioned at a different distance was adjusted so as to subtend the same retinal image, the larger stimuli were responded to faster than the smaller ones. This effect can be attributed to size constancy affecting RT. In keepeing with that, when size constancy cues were removed by using a pinhole for stimulus viewing, RT reflected stimulus retinal size only. In further experiments I employed visual illusion, such as Ponzo's and Ebbinghaus' to induce misperception of size. In accord with the size constancy result, stimuli perceived as larger were responded to faster than those perceived as smaller, despite retinal size was the same. In sum, all these results demonstrate that simple RT reflects perceiver rather than retinal stimulus size.

碩士
華梵大學
工業工程與經營資訊學系碩士班
105
The larger of two equally weighted objects is judged to be lighter when lifted. This phenomenon is commonly known as the size-weight illusion. Size-weight illusion could be important for the study of flipping tasks, since any decrease in perceived heaviness accompanying larger woks could lead the cook to exceed the limits of safety. Though size-weight illusion has been studied extensively in experiment psychology, empirical study on flipping tasks until now has not been conducted. Therefore, this study intent to investigate the effects of wok size on the size-weight illusion of stir flipping tasks for Chinese cooks. This study recruited 16 subjects to conduct flipping task, and to investigate the perceived heaviness, perceived volume, and perceived exertion of the different combinations of object size (Diameter of 32, 37, 40 cm) and mass (1.5, 2.1 and 2.4 kg). The mass affects significantly on the perceived heaviness, and perceived exertion however, couldn’t affect significantly on the perceived volume. The effects of the wok size on the perceived heaviness, perceived volume, and perceived exertion is significant. The result showed that the size-weight illusion exists in the Chinese wok. As the volume of the wok’s diameter from 32 to 40 cm, the reports of perceived heaviness decreased 27 % and 13 % repectively for the Chinese wok.

The ability to accurately predict object weight is essential for skilled manipulation and recent studies suggest that such prediction is based, in part, on learned size-weight maps associated with families of objects. Weight prediction based on size-weight maps is also involved when judging weights; there is strong evidence that weight judgments are biased by expected weight, based on size. This bias is revealed by the size-weight illusion (SWI) whereby the smaller of two equally weighted and otherwise similar objects is judged to be heavier because it is heavier than expected based on its size. The overall aim of the current set of studies was to examine how size-weight maps for different families of objects are organized and represented at the perceptual and sensorimotor levels. We found that distinct and independent size-weight maps, used to predict weight, were used when lifting objects and judging their weights. At the perceptual level, interference between size-weight maps for the different sets of cubes was observed; participants could learn the inverted size-weight relationship for the green cubes when experienced alone but not when experienced along with the black cubes with a normal size-weight relationship. However, about half of participants learned to scale lift forces accurately for both sets of cubes indicating that the sensorimotor system can learn, without interference, opposite size-weight maps. We further investigated why not all participants learned to accurately scale their lift forces and found that learning to lift objects with different and arbitrary size weight maps involves visuomotor working memory resources. Moreover, an outside task that steals attentional resources can interfere even after previous learning of the size-weight maps.
Thesis (Master, Psychology) -- Queen's University, 2011-09-30 12:51:49.413

A size-weight illusion (SWI) occurs when a large object and small object of equal mass but different volume are lifted and the small object is perceived as heavier than the large object. All previous studies of the SWI used similar coloured objects and found that individuals initially use more force to lift the large object, compared to the small object but then use similar forces for the two objects on subsequent lifts. In contrast to the change in lifting forces over trials, the perceptual illusion stays consistent across all trials. The goal of the current study was to determine if introducing different colours for the SWI stimuli could alter participants’ expectations about the masses of the two objects and therefore modify the perceptual SWI. Participants lifted SWI stimuli that were either identical in colour or stimuli of different colour.

碩士
臺北市立教育大學
視覺藝術學系碩士班
98
The study investigated effects of art versus non-art and grade on Muller-Lyer optical illusion size. An instrument composed of four types of figures (basic-angle/standard, basic-angle/vertical-separate, altered-angle/standard, and altered-angle/vertical-separate), each containing eleven choices, was used to measure students’ illusion size. Participants from first to ninth grades were tested. The results are the followings: 1) the differences between students from first to ninth grades were not significant; 2) the difference between art and non-art students was significant with the average illusion size of art students lower than that of non-art students; 3) the difference between standard and vertical-separate was not significant; 4) the difference between basic-angle and altered-angle was significant with the average illusion size of altered-angle lower than that of basic-angle.

碩士
華梵大學
工業工程與經營資訊學系碩士班
106
Previous studies showed that the effect of box size on the size-weight illusion was significant. However, until now this size-weight illusion of the soup pot size has not been formally studied and standardized. Therefore, the purpose of this study is to investigate the size-weight illusion of the size of soup pot. A total of 12 male subjects were recruited to conduct lifting task, and to investigate the perceived heaviness, perceived volume, and perceived exertion of the different combinations of the size of soup pots (diameter of 30, 36 and 45 cm) and mass (3.0, 6.6 and 13.8 kg) relative to the standard stimulus(40 cm, 9.0 kg). After collecting and analyzing the data, it was found that the soup pot size had significant effect on the perceived heaviness and perceived volume, but it had no significant effect on the perceived exertion. While the effects of the mass on the perceived heaviness, perceived volume, and perceived exertion were significant. Overall, the subjects perceived larger soup pots to be light than smaller soup pots of the same mass. As the volume of the stimuli increased from 30 cm diameter to 45 cm diameter, the reports of perceived heaviness deceased by about 10.83%. The result showed that the size-weight illusion exists in the soup pot lifting for chefs.

碩士
高雄醫學大學
行為科學研究所碩士班
92
In our daily life, the judgments of size and distance seem very fast and automatic. Sometimes, we find exceptions. In some special situations, we have size and distance perception which were disagree with the reality, that we called illusions. The purpose of the research is to debate that in the dichoptic presentation, will manipulate different kinds of depth cues effecting the judgments of size and distance ? The purpose of experiment 1 was to access the effects of task types, depth cues and location of moons. The results show that task types and depth cues may not cause an effect to the judgments of the subjects, but the location of moons does. In experiment 1, size-distance invariance hypothesis(SDIH) was been supported. But we can''t find measurable relationship between the distance and size perceptions. The purpose of experiment 2 was to access the effects of task types and depth cues. The results show that depth cues may not cause an effect to the judgments of the subjects. In the dichoptic presentation, the subjects may judge the distance better. In spite of the effects of SDIH is very strong, but we still can''t predict it through the formula absolutely.

Tese de mestrado, Psicologia (Área de Especialização em Cognição Social Aplicada), Universidade de Lisboa, Faculdade de Psicologia, 2019
Learning to read is an intensive visual activity that, through perceptual learning, leads to changes on early visual brain areas, including the primary occipital cortex, V1. The Ebbinghaus illusion is known to depend on V1 functioning. Furthermore, previous studies suggest that children are less susceptible to this illusion than adults. Although this phenomenon has mostly been attributed to cognitive development, a recent study showed that it could be attributed to schooling, given its relation with the number of years of education in Himba people. In this thesis, we hypothesized that literacy, instead of schooling, is the relevant cultural variable influencing susceptibility to this illusion. We explored this hypothesis in two experiments. In Experiment 1, we examined literate, ex-illiterate and illiterate adults, matched in age and sex and from the same socioeconomic and cultural background. In Experiment 2, we compared two groups of children matched in age and cognitive development, who differed only in schooling/literacy: pre-literate preschoolers vs. first-grade children learning to read. Experiment 2 provided convergent evidence and, by comparing children and adult readers, allowed to examine if development influences susceptibility to this illusion. Participants performed a size discrimination task, where they decided which of two circles was the largest. In the first block, these circles where surrounded by other circles or inducers, which could have a congruent or incongruent size relative to the inner target circles (that is, the larger inner circle surrounded by large or by small inducers, respectively). In the second block, participants performed the same task without inducers to ensure that any difference to be found between groups in the block with inducers would not be due to differences in veridical size discrimination abilities. As expected, non-readers were less susceptible to the illusion than readers, which evidences the impact of learning to read in early visual processing.
Aprender a ler é uma atividade visual intensa que leva a mudanças em áreas visuais precoces, incluindo o córtex occipital primário, V1. A ilusão de Ebbinghaus depende do funcionamento de V1. Ademais, estudos prévios sugeriram que as crianças são menos suscetíveis a esta ilusão do que adultos. Apesar de este fenómeno ser tendencialmente atribuído ao desenvolvimento cognitivo, um estudo recente demonstrou que este podia ser atribuído à escolarização, uma vez que se observou uma relação entre os anos de escolarização em pessoas Himba e a suscetibilidade a esta ilusão. Nesta dissertação, hipotetizou-se que a literacia, ao invés da escolarização, é a variável cultural relevante que influencia a suscetibilidade. Explorou-se esta hipótese em duas experiências. Na Experiência 1, examinou-se adultos letrados, ex-iletrados e iletrados, emparelhados em sexo, idade, estatuto socioeconómico e pertencentes à mesma cultura. Na Experiência 2, comparou-se dois grupos de crianças, emparelhados em idade e desenvolvimento cognitivo, que diferiam apenas em escolarização/literacia: crianças pré letradas em jardins de infância e crianças do 1º ano a aprender a ler. A Experiência 2 serviu para fornecer convergência evidente e também permitiu examinar se o desenvolvimento influencia a suscetibilidade à ilusão, através da comparação entre crianças e adultos leitores. Os participantes desempenharam uma tarefa de discriminação de tamanho, em que tinham que decidir qual de dois círculos era maior. No primeiro bloco, os círculos eram rodeados por outros círculos, ou indutores, que podiam ter tamanho congruente ou incongruente relativamente ao tamanho do círculo central alvo (isto é, o círculo central maior podia estar rodeado de indutores grandes ou pequenos, respetivamente). No segundo bloco, os participantes desempenharam a mesma tarefa sem indutores para assegurar que qualquer diferença encontrada entre grupos não se deve a diferenças em habilidades de discriminação de tamanho verídico. Como era esperado, os não-leitores foram menos suscetíveis à ilusão do que os leitores, o que evidenciou o impacto da literacia no processamento visual precoce.

碩士
華梵大學
工業工程與經營資訊學系碩士班
96
Manual materials handling (MMH) has been identified as one of the major causes of back injuries and musculoskeletal disorders to industrial workers and cost to industry. Foreign researches showed that the lifters perceive larger objects to be lighter than smaller objects of the same mass. This phenomenon is commonly known as the size-weight illusion. The decrease in perceived heaviness accompanying larger objects could lead the lifter to exceed the limits of safety and cause the musculoskeletal injuries. However, until now this size-weight illusion has not been studied in our country. In addition, this phenomenon also has not been verified by psychophysical research for foreign and native researchers. Therefore, the purposes of this study is to investigate the size-weight illusion of individuals and team lifting and to evaluate the effect of size-weight illusion on psychophysically determination of maximum acceptable weights (MAWL). The first, this study recruited twenty-eight subjects (18 men, 10 women) to conduct individual (experiment 1) and team (experiment 2) lifting, and to investigate the perceived heaviness, perceived volume, and perceived exertion of the different combinations of object size (103, 143 and 183 cubic inches) and mass (3.0, 6.6 and 9.0 kg). The mass affects significantly on the perceived heaviness, however, couldn’t affect significantly on the perceived volume and perceived exertion. The effects of the object size on the perceived heaviness, perceived volume, and perceived exertion is significant. The result showed that the size-weight illusion exists in the individual and team lifting for Chinese participants. As the volume of the stimuli increased from 103 to 183 cubic inches, the reports of perceived heaviness decreased 20 % and 26 % for individual and team lifting, respectively. In addition, the effects of sex and ethnic difference were not significant. The second, this study used psychophysical method and the same subjects to evaluate the effect of size-weight illusion on the MAWLs of different combinations of object size (103, 143 and 183 cubic inches) and frequency (one time maximum, 1 lift/min and 4 lifts/min) for individual (experiment 3) and team (experiment 4) lifting. The results showed that whether lifted by an individual or a team, larger containers are perceived to be substantially lighter than smaller containers, and the subjects lift more hardly accompany with an increase of volume. For individual lifting, the decrease of the MAWLs (100, 95 and 76 % relative to small containers) is larger than the revised horizontal and coupling multiplier of NIOSH (1991) (100, 87 and 73 % relative to small containers). For team lifting, the decrease of the MAWLs (100, 110 and 108 relative to small containers) is also larger than the revised horizontal and coupling multipliers of NIOSH (1991) (100, 96 and 87 % relative to small containers). This indicated that the effect of size-weight illusion on the MAWL is significant.