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1
Fair, Joseph Edward. "Infant Facial Discrimination and Perceptual Narrowing." BYU ScholarsArchive, 2009. https://scholarsarchive.byu.edu/etd/2154.
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During the early stages of infant development the capacity for perceptual (i.e., visual) discrimination is shaped by infants' perceptual experience. Perceptual narrowing is one process hypothesized to account for developmental change. Perceptual narrowing research often demonstrates that infants before 6 months of age are able to discriminate a wide variety of events whereas infants beyond 6 months of age seemingly "lose" some perceptual abilities. Two investigations are proposed to examine the claim that younger, but not older infants can discriminate faces across species. The purpose of Experiment 1 was to determine whether an increase in familiarization and trial times would result in cross-species facial (i.e. faces of macaques) discrimination in 12-month-olds. The hypothesis was supported, adding evidence that perceptual discrimination becomes more constricted, or less efficient with age, but does not decline. Experiment 2 examined whether reducing both the time of familiarization and comparison time by 50% would allow infants sufficient time to discriminate. Results were consistent with the hypothesis and previous studies were corroborated. These findings highlight the important role of perceptual experience in young infants' perceptual discrimination abilities and provide a greater degree of clarity regarding present use of the concept perceptual narrowing.
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Lavis, Yvonna Marie Psychology Faculty of Science UNSW. "An investigation of the mechanisms responsible for perceptual learning in humans." Publisher:University of New South Wales. Psychology, 2008. http://handle.unsw.edu.au/1959.4/42882.
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Discrimination between similar stimuli is enhanced more by intermixed pre-exposure than by blocked pre-exposure to those stimuli. The salience modulation account of this intermixed-blocked effect proposes that the unique elements of intermixed stimuli are more salient than those of blocked stimuli. The inhibition account proposes that inhibitory links between the unique elements of intermixed stimuli enhance discrimination. The current thesis evaluated the two accounts in their ability to explain this effect in humans. In Experiments 1 and 2, categorisation and same-different judgements were more accurate for intermixed than for blocked stimuli. This indicates that intermixed pre-exposure decreases generalisation and increases discriminability more than does blocked pre-exposure. In Experiments 3 ?? 5, same-different judgements were more accurate when at least one of the two stimuli was intermixed. This enhanced discrimination was not confined to two stimuli that had been directly intermixed. These results are better explained by salience modulation than by inhibition. Experiments 6 ?? 8 employed dot probe tasks, in which a grid stimulus was followed immediately by a probe. Neither intermixed nor blocked stimuli showed facilitated reaction times when the probe appeared in the location of the unique element. In Experiments 9 ?? 11 participants learned to categorise the intermixed unique elements more successfully than the blocked unique elements, but only when the unique elements were presented on a novel background during categorisation. Experiments 6 ?? 11 provide weak evidence that the intermixed unique elements are more salient than their blocked counterparts. In Experiment 12, participants were presented with the shape and location of a given unique element, and were required to select the correct colour. Performance was more accurate for intermixed than for blocked unique elements. In Experiment 13, participants learned to categorise intermixed, blocked and novel unique elements. Performance was better for intermixed than for blocked and novel unique elements, which did not differ. None of the proposed mechanisms for salience modulation anticipate these results. The intermixed-blocked effect in human perceptual learning is better explained by salience modulation than by inhibition. However, the salience modulation accounts that have been proposed received little support. An alternative account of salience modulation is considered.
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Mauney, Lisa M. "Individual Differences in Cognitive, Musical, and Perceptual Abilities." Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/13972.
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The increasing use of auditory graphs and sonifications in technology is leading to a wider variety of system users, which, in turn, suggests a need for research in how differences between individual listeners affect sound interpretation. As a first step in this arena, the current study investigates the question of whether or not cognitive abilities and musical experience predict frequency and tempo discrimination in individuals. Participants in the study were 30 undergraduate students from Georgia Institute of Technology and 20 adults from the Atlanta, Georgia community. In the cognitive ability session, participants completed the Operation Span (Ospan) task as a measure of working memory capacity and the Ravens Progressive Matrices task as a measure of spatial reasoning. In the auditory discrimination session, participants performed a tempo and a frequency discrimination task. Demographics on age, gender, handedness, years of playing a musical instrument, and years of formal musical training were also collected.
A correlational analysis of all variables was performed. Paired-samples t-tests on the Weber fractions of the six threshold means were also performed to determine if there were any significant differences between the frequency thresholds and the tempo thresholds. Lastly, multiple hierarchical regressions were performed on each of the six dependent variables to identify significant predictors of frequency and tempo discrimination. The paired samples t-tests show a significant difference between 250 Hz and 840 Hz and between 250 Hz and 1600 Hz, a violation of Webers Law. However, this violation of Webers Law may be explained by the small sample size used in the study. The t-tests also show a significant difference between the means of 150 ms and 250 ms and between the means of 250 ms and 350 ms. The results of the regression analyses show that good performance on Ravens seems to predict lower thresholds at 1600 Hz. The results also show that good scores on Ospan appear to predict lower thresholds at 350 ms ICI. In addition to these significant predictors from the regression analyses, there are many significant correlations that provide further support that cognitive abilities are related to frequency and tempo discrimination.
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Lalonde, Jasmin. "Task-dependent transfer of perceptual to memory representations during delayed spatial frequency discrimination." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33911.
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Discrimination thresholds were obtained during a delayed spatial frequency discrimination task. In Experiment 1, we found that presentation of a mask 3 s before onset of a reference Gabor patch caused selective interference in a subsequent discrimination task. However, a 10 s interval abolished this masking effect. In Experiment 2, the mask was associated with a second spatial frequency discrimination task so that a representation of the mask had to be coded into short-term perceptual memory. The presence of this second discrimination task now caused similar interference effects on the primary discrimination task at both the 3 s and 10 s ISI conditions. The different results from these two experiments are best explained by a two-step perceptual memory mechanism. The results also provide further insight into the conditions under which stimulus representations are shared between the perceptual and memory domains.
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Chen, Xing. "Perceptual learning of contrast discrimination and its neural correlates in macaque V4 and V1." Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2403.
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We make frequent evaluations of subtle contrast differences in our visual environment, and often under challenging illumination conditions, whether photopic, scotopic or mesopic. Our contrast discrimination abilities are rigorously honed from an early age, and we continue to carry out these fine perceptual judgments throughout our lifetimes. Thus, the issue of whether substantial improvement in contrast discrimination is possible during later periods in life, such as during adulthood- and the circumstances that allow this- has sometimes come under discussion. Our adult macaque subjects underwent extensive training on a contrast discrimination task, in which stimuli were positioned at a variety of peripheral and parafoveal locations. We present clear evidence of contrast perceptual learning at the behavioural level and show that these changes have neuronal correlates primarily in V4, rather than in V1. Learning was specific to stimulus location and spatial frequency, but was transferable across orientations; it took place to a limited degree under stimulus roving conditions, and could be either facilitated or impeded by the addition of flanker stimuli, depending on the subject. Upon removal of flankers, levels of psychometric and neurometric performance returned to their pre-flanker state. In V4, learning-induced changes encompassed a shift in the point of neurometric equality and the semi-saturation constant (C50) towards the trained contrast; a decrease in noise correlations across channels; and an increase in choice probability. In V1, enhancements in performance were characterised by an increase in spike discriminability; a shift in the point of neurometric equality and the C50 towards the trained contrast(s); and a widening in the range and a steepening of the contrast response function, during the early phase of training. Deteriorations in performance were accompanied by the reverse effects on V1 activity; furthermore, a general decrease in V1 firing rates occurred when training was carried out over an extended period of time, after performance had reached its peak.
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Taylor, Andrea. "Assessing the Effects of Stress Resilience Training on Visual Discrimination Skills: Implications for Perceptual Resilience in U.S. Warfighters." VCU Scholars Compass, 2012. http://scholarscompass.vcu.edu/etd/2745.
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Current military operational environments are highly improvised and constantly evolving, threatening the lives of U.S. warfighters. For instance, since 2001, 60% of all hostile casualties and 65% of hostile injuries in the Middle East theater have been attributed to improvised explosive devices (IEDs). IEDs are powerful physical weapons, and the stressful atmosphere they, and other operational challenges create, can also result in a range of psychological dysfunctions, including anxiety, depression, alcohol abuse, and Post-Traumatic Stress Disorder (PTSD). Not only are these issues concerning for mental health reasons, they are also problematic in terms of combat performance. Extreme arousal (i.e., stress) negatively affects performance through the suppression of cognitive and physiological resources, which inhibits verbal, perceptual, and motor performance. Perceptual abilities are particularly susceptible to the effects of acute hyperarousal, and the degradation of these abilities may limit warfighters’ threat detection skills. Therefore, military researchers are interested in whether and how the visual perceptual field is changed under stress, and the Services are making predeployment training programs a priority, in an attempt to mitigate these concerns. This dissertation first outlines the cognitive processes related to visual perceptual abilities and how these processes are negatively affected by acute arousal. Current training programs in perceptual skills and stress tolerance are then described, along with recommendations for areas of improvement within the status quo. Based on these recommendations, an experimental procedure and five hypotheses were designed to assess training effects on visual perceptual skills and performance under stress. Experimental outcomes suggest that participants who were trained using a novel integrated perceptual skills plus stress resilience (“perceptual resilience”) program performed faster and with higher accuracy during a stressful threat detection task than participants trained using a perceptual skills-only program and participants trained using an existing status-quo knowledge trainer. Participants in this perceptual resilience training group also reported lower feelings of acute stress and anxiety immediately post-task than the two other training groups who did not receive the stress resilience training component. Based on these outcomes, implications for future military-specific training development, study limitations, and recommendations for future research is presented.
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Weddell, Di, and n/a. "The relationship of colour systems to the perceptual discrimination of colour in Year 7 students." University of Canberra. Education, 1995. http://erl.canberra.edu.au./public/adt-AUC20061110.113934.
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Colour mixing is fundamental to learning to paint. Students in visual
art classes in secondary schools face problems in manipulating paint
and discriminating colour. The kinds of base paints to be presented
to students could be an important factor in learning about colour
relationships and pigments.
The purpose of this study was to determine whether Year 7 students
generating colour mixes with paint using a triad of magenta, cyan
and yellow were able to mix and discriminate more colours than if
they used a triad of red(scarlet red), blue (ultramarine light) and
yellow (lemon yellow) which is a base triad commonly used in
schools.
The Weddell Colour Discrimination Test was developed for use in
this study which was a test that involved colour mixing with paint.
The study used quasi-experimental designs for both a pilot study and
a main study.
Results indicated a significant difference in the ability to mix paint
advantage of groups that used cyan , magenta and yellow.
Implications for the use of particular colour triads in art classrooms
and methods of teaching colour theory have emerged from this
study. The Weddell Colour Discrimination test instrument developed
in this study could be useful as both a diagnostic tool and a teaching
tool as well as a data gathering method for further research.
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King, Robert A. "Perceptual grouping selection rules in visual search : methods of sub-group selection in multiple target visual search tasks." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/32821.
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Carnot, Mary Jo. "The role of identical component information in similarity, discrimination, grouping and detection tasks." The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1100589505.
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Gong, Mingliang. "Orientation discrimination in periphery: Surround suppression or crowding?" Miami University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=miami1430433449.
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Aime, Mattia. "Circuit mechanisms for encoding discriminative learning in the dorsal prefrontal cortex of behaving mice." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0805/document.
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Chez les mammifères, le néocortex constitue une structure remarquablement plastique assurant leurs multiples capacités d’adaptation et d’apprentissage. Par exemple, l’apprentissage associatif permet à chaque individu d’apprendre les relations entre un événement particulier (un danger par exemple) et les signaux environnementaux qui y sont associés, afin d’en anticiper les conséquences s’il se reproduit dans le futur. Dans le cas de la peur conditionnée, l'apprentissage associatif améliore les capacités de discrimination des signaux de menace et de sécurité, garantissant ainsi une représentation précise de l'environnement. Ce processus comportemental est en partie dépendant de l'interaction entre deux structures cérébrales: le cortex préfrontal (PFC) et le complexe basolatéral de l'amygdale (BLA). Bien que le PFC puisse encoder à la fois les mémoires de menace et de sécurité qui seraient recrutées préférentiellement après l'apprentissage, on ignore toujours si une telle représentation discriminative existe réellement, et si oui, les mécanismes neuronaux et synaptiques qui en sont à l'origine. Au cours de mon travail de thèse, j'ai démontré que l'activité des neurones excitateurs du PFC est nécessaire à la discrimination entre les signaux de menace et de sécurité grâce à la formation d'ensembles spécifiques de neurones. Au cours de l'apprentissage, les neurones pyramidaux sont potentialisés et recrutés au sein de ses ensembles grâce à l'association au niveau dendritique d'événements synaptiques non-linéaires issus des entrées sensorielles avec des entrées synaptiques provenant de la BLA. En conclusion, nos données fournissent la preuve d'un nouveau mécanisme synaptique qui associe, pendant l'apprentissage, l'expérience perçue avec l’état émotionnel transmis par la BLA permettant ainsi la formation d'ensembles neuronaux dans le cortex préfrontalThe ability of an organism to predict forthcoming events is crucial for survival, and depends on the repeated contingency and contiguity between sensory cues and the events (i.e. danger) they must predict. The resulting learned association provides an accurate representation of the environment by increasing discriminative skills between threat and safety signals, most likely as a result of the interaction between the prefrontal cortex (PFC) and the basolateral amygdala (BLA). Although it suggests that local neuronal networks in the PFC might encode opposing memories that are preferentially selected during recall by recruiting specific cortical or subcortical structures, whether such a discriminative representation is wired within discrete prefrontal circuits during learning and by which synaptic mechanisms remain unclear. Here, the work at issue demonstrates that discrimination learning of both safe and fear-conditioned stimuli depends on full activity of the frontal association cortex, and is associated with the formation of cue-specific neuronal assemblies therein. During learning, prefrontal pyramidal neurons were potentiated through sensory-driven dendritic non-linearities supported by the activation of long-range inputs from the basolateral amygdala (BLA). Taken together, these data provide evidence for a new synaptic level mechanism that coincidently link (or meta-associate) during learning features of perceived experience with BLA mediated emotional state into prefrontal memory assemblies
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Jantzen, Kelly J. "Evidence that plasticity in SI is not responsible for perceptual improvement resulting from training on a tactile frequency discrimination task." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0024/NQ51875.pdf.
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Posid, Tasha Irene. "The small-large divide: The development of infant abilities to discriminate small from large sets." Thesis, Boston College, 2015. http://hdl.handle.net/2345/bc-ir:104371.
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Thesis advisor: Sara CordesThesis advisor: Ellen Winner
Evidence suggests that humans and non-human animals have access to two distinct numerical representation systems: a precise "object-file" system used to visually track small quantities (<4) and an approximate, ratio-dependent analog magnitude system used to represent all natural numbers. Although many studies to date indicate that infants can discriminate exclusively small sets (e.g., 1 vs. 2, 2 vs. 3) or exclusively large sets (4 vs. 8, 8 vs. 16), a robust phenomenon exists whereby they fail to compare sets crossing this small-large boundary (2 vs. 4, 3 vs. 6) despite a seemingly favorable ratio of difference between the two set sizes. Despite these robust failures in infancy (up to 14 months), studies suggest that 3-year old children no longer encounter difficulties comparing small from large sets, yet little work has explored the development of this phenomenon between 14 months and 3 years of age. The present study investigates (1) when in development infants naturally overcome this inability to compare small vs. large sets, as well as (2) what factors may facilitate this ability: namely, perceptual variability and/or numerical language. Results from three cross-sectional studies indicate that infants begin to discriminate between small and large sets as early as 17 months of age. Furthermore, infants seemed to benefit from perceptual variability of the items in the set when making these discriminations. Moreover, although preliminary evidence suggests that a child's ability to verbally count may correlate with success on these discriminations, simply exposure to numerical language (in the form of adult modeling of labeling the cardinality and counting the set) does not affect performance
Thesis (PhD) — Boston College, 2015
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Psychology
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Sawadogo, Ousmane. "PERCEPTION OF /q/ IN THE ARABIC /q/-/k/ CONTRAST BY NATIVE SPEAKERS OF AMERICAN ENGLISH: A DISCRIMINATION TASK." OpenSIUC, 2015. https://opensiuc.lib.siu.edu/theses/1695.
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AN ABSTRACT OF THE THESIS OF Ousmane Sawadogo, for the Master of Arts degree in Applied Linguistics and TESOL, presented on May 4, 2015, at Southern Illinois University Carbondale. TITLE: PERCEPTION OF /q/ IN THE ARABIC /q/-/k/ CONTRAST BY NATIVE SPEAKERS OF AMERICAN ENGLISH: A DISCRIMINATION TASK MAJOR PROFESSOR: Dr. Soo Jung Chang Studies on speech perception have suggested that non-native sound perception is influenced by the listener’s native language. Non-native sound contrast perception depends on a given sound’s similarity or dissimilarity to the listener’s equivalent native language sound. The Perceptual Assimilation Model (PAM) posits that it is difficult to distinguish non-native sounds when they are perceived as very similar to native sounds and are thus assimilated to a native sound category, but identification is easier when the non-native is sound is dissimilar to a native sound (Best, 1994a). The present study investigated whether native speakers of American English would display very good discrimination of /q/ in the Arabic /q/-/k/ contrast as predicted by the PAM. The Speech Learning Model (SLM) posits that non-native perception is position-sensitive and hypothesizes that the listener’s perception of non-native sounds would vary from one position to another (Flege, 1995). The current study also aimed to investigate whether the discrimination of the Arabic /q/-/k/ contrast would be position-sensitive. The current study also investigated the effect of the vocalic context on the discrimination of /q/. Participants consisted of 22 (6 male and 16 female) native speakers of American English who were students or faculty members at Southern Illinois University. Their ages ranged between 19 and over 50. The data were collected through an online AXB discrimination task survey. Target sounds were represented in 108 pseudowords so that the sounds could be contrasted in minimal pairs. The environments were word-initially followed by /i/, /u/, and /a/; word-medially, between two instances of /i/, two instances of /u/, and two instances of /a/; and word-finally, preceded by /i/, /u/, and /a/. Two pseudoword pairs were selected for each contrast. Four AXB combinations (AAB, ABB, BAA, and BBA) were generated for each of the nine contrasts, which resulted in a total of 36 stimuli. The participants were requested to click on a button to listen to the recordings of these word pairs and check the right answer. The findings were consistent with predictions made by PAM that native speakers of American English would have a very good discrimination of /q/ in the Arabic /q/-/k/ contrast. The results suggested that the uncategorized versus categorized (UC) type could also be of excellent discriminability. SLM was not totally supported because the differences were not statistically significant. However, the data indicated that some positions resulted in better discrimination scores than other positions and that certain vowels likewise resulted in better vocalic discrimination scores. Keywords: Discrimination task, non-native sound perception, Arabic /q/-/k/ contrast, position-sensitive, context-sensitive, vocalic context, UC type assimilation, Speech Leaning Model (SLM), Perceptual Assimilation Model (PAM).
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Galois, Patrick. "Turtle nest sensory perception by raccoon (Procyon lotor) and striped skunk (Mephitis mephitis) : an approach through discrimination learning of potential nest cues." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=42038.
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Egg predation may be the most important mortality factor for North American turtles. This predation can destroy 50-90% of nests in an area. The major predators are striped skunks (Mephitis mephitis) and raccoons (Procyon lotor). Despite differences in their habits and diet, these species appear equally efficient in turtle egg predation, even though these eggs represent a very small portion of their annual food intake. Sight, olfaction, touch and hearing could be used by these predators to find the nests. The aim of this study was to document intra and inter-specific differences in the perception of possible nest-cues used by raccoon and striped skunk. Choice-tests based on food-conditioning were carried out with two visual cues (dark and smooth surface), one olfactory cue (turtle urine) and one tactile cue (soil compaction). Subject performances (number of trials to obtain 80% success rate in the different tests) were compared to assess intra and inter-species, and skunk inter-age differences in sensory perception and learning abilities. As expected raccoons learned the tactile cue discrimination faster than the visual cue discriminations. The tactile cue discrimination was learned as fast as the olfactory cue. As expected skunks learned the olfactory cue discrimination faster than other cue discriminations. When compared, the olfactory cue appeared to be as important for both species even though raccoons had faster learning rates than skunks in all the tests except for one visual test. Juvenile skunks learned faster than adult skunks with four out of six juveniles performing better in the olfactory test. Olfaction may play an important role in nest localization by raccoons and skunks, and sight may also play a role for raccoons. Learning turtle nest cues while with their mother could facilitate their future ability in locating turtle nests.
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Albareda, Castellot Bàrbara. "Developmental changes in vowel perception: how input interplays with initial perceptual biases." Doctoral thesis, Universitat Pompeu Fabra, 2010. http://hdl.handle.net/10803/7213.
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The present dissertation aims at analyzing the interplay between initial acoustic biases and language exposure during acquisition of language in the first year of life. This is a critical period in development because it is when phonetic categories are attuned to the native language. This goal is addressed by integrating the results from two developmental studies. The first study explores the presence of asymmetries in vowel perception in infants from 4 to 12 months of age, as a function of the acoustic salience and distributional properties in the test language. The second study investigates the previous contrasting results on vowel perception in 8-month-old infants growing in bilingual environments, and in particular and their relationship with task demands and the properties of the bilingual input. The results emerging from these studies point to two developmental trends. On one hand, asymmetries in vowel perception are modulated by acoustic biases before and during perceptual reorganization, and by distributional cues after perceptual reorganization. On the other hand, discrimination abilities of 8-month-old bilinguals parallel those of monolinguals when tested with an Anticipatory Eye Movement procedure, highlighting the importance of task demands in determining infants' performance.L'objectiu d'aquesta tesis és analitzar la dinàmica que s'estableix entre els biaixos acústics i l'experiència amb el llenguatge durant el primer any de vida. Aquest és un període decisiu durant el qual les categories fonètiques s'ajusten a les propietats de la llengua materna. Aquest objectiu s'assoleix integrant els resultats de dos estudis. En el primer estudi s'explora la presència d'asimetries en la percepció de les vocals en bebès de 4 a 12 mesos d'edat, en funció de la saliència acústica i les propietats distribucionals de la llengua. El segon estudi investiga els resultats contradictoris obtinguts amb bebès de 8 mesos d'edat bilingües, i la seva relació amb les demandes de la tasca i les propietats de l'input bilingüe. Els resultats d'aquests estudis indiquen dos tendències al desenvolupament. Per una banda, que les asimetries en la percepció de les vocals són modulades per biaixos acústics abans i durant la reorganització perceptiva i per les propietats distribucionals després de la reorganització perceptiva; per l'altra banda, els resultats mostren que les habilitats de discriminació dels bilingües de 8 mesos d'edat són corresponents a les dels monolingües quan es fa servir un procediment d'anticipació de la mirada, posant en rellevància la importància de les demandes de la tasca en determinar el rendiment dels bebès.
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Hodgson, Eric P. "The interaction of transient and enduring spatial representations using visual cues to maintain perceptual engagement /." Oxford, Ohio : Miami University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1217959226.
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Marchelli, Leopoldo Francisco Barletta. "Envolvimento de processos atencionais em tarefas de escolhas relacionadas à detecção e discriminação de estímulos sonoros, em ratos: avaliação comportamental." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/41/41135/tde-22032017-104659/.
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A influência da atenção em processos de tomada de decisões é frequentemente avaliada através da tarefa denominada \"two-alternative choice\", em que os animais são treinados a emitir respostas baseadas na detecção e discriminação de dois estímulos discretos. Pela sua própria natureza, as possibilidades de se manipular a demanda atencional nessas tarefas é relativamente restrita. O desenho experimental básico adotado no presente conjunto de experimentos almejou possibilitar a variação das demandas atencionais durante o desempenho de uma tarefa que envolve discriminação auditiva, por meio da apresentação de sequências variáveis de \"beeps\" de mesma frequência (estímulos sonoros não informativos de 6 kHz) apresentados bilateralmente, seguidos de um estímulo informativo, um beep distinto de 3 ou 10 kHz, apresentado (1) bilateralmente, cuja frequência sinaliza a resposta a ser emitida (Experimento 1), ou (2) unilateralmente, cujo local de apresentação sinaliza a resposta a ser emitida (Experimento 2). No Experimento 1 observou-se uma redução dos tempos de reação para os estímulos alvo e uma redução da porcentagem de erros de comissão em função do aumento do número de estímulos não informativos, para ambos os estímulos informativos numa primeira fase e apenas para o de 10 kHz após a reversão da resposta inicialmente treinada. Curiosamente, os tempos de reação para o estímulo alvo de 10 kHz foram maiores em relação aos exibidos para o estímulo alvo de 3 kHz. Por outro lado, a redução da porcentagem de erros de comissão foi mais acentuada nas tentativas envolvendo o estímulo alvo de 10 kHz. No Experimento 2 houve aumento dos tempos de reação em função do aumento do número de estímulos não informativos apresentados. Os tempos de reação para o estímulo alvo de 10 kHz apresentado no lado esquerdo foram maiores em relação ao lado direito e também em relação ao estímulo alvo de 3 kHz apresentado no lado esquerdo ou direito. No mesmo sentido, houve menor percentagem de respostas corretas e maior percentagem de erros de comissão quando o estimulo alvo de 10 kHz foi apresentado no lado esquerdo. A porcentagem de respostas corretas assim como a redução dos tempos de reação são maiores no Experimento 2 em relação ao Experimento 1, sugerindo que nas presentes condições experimentais a identificação da fonte sonora é mais prontamente detectada do que a diferença de frequência dos estímulos alvo. Em conjunto os resultados obtidos mostram que o engajamento e manutenção de recursos atencionais longo do tempo variam em função da natureza periférica ou simbólica do estímulo alvo utilizado. A variação da frequência sonora dos estímulos alvo apresentados após uma sequência de estímulos não informativos também influencia o desempenho dos animaisThe influence of attention in decision making processes is usually evaluated using two-alternative choice tasks in which the subjects react relying on detection and discrimination of two discrete stimuli. The possibilities of manipulating attentional demands in this kind of task is relatively restricted. The experimental design employed in the present experiments aimed at providing ways to manipulate the attentional demands during performance of an auditory task. This was achieved by presenting variable sequences of non-informative 6 kHz beeps, bilaterally, followed by one distinctive (either 3 or 10 kHz) informative beep presented either (1) bilaterally such that the frequency identifies the required response (Experiment 1) or (2) unilaterally such that the place of presentation identifies the required response (Experiment 2). In Experiment 1 data showed a decrease in both reaction times for target stimuli and percentage of comission errors as a function of the number of non-informative stimuli. These effects occurred early in training for both, 3 and 10 kHz target stimuli, and only for 10 kHz target stimulus after reversal of training. Interestingly, reaction times for 10 kHz target stimuli were longer relative to those seen for 3 kHz target stimuli. In contrast, reduction of the percentage of comission errors was stronger in trials using 10 kHz target stimuli. In Experiment 2 reaction times increased as a function of the increase in the number of non-informative stimuli. In addition, reaction times for 10 kHz target stimuli presented in the left side were longer as compared to both 10 kHz target stimuli presented in the right side and 3 kHz stimuli presented in both sides. Congruently, a smaller percentage of correct responses and a greater percentage of comission errors were seen when the 10 kHz target stimuli were presented in the left side. The percentage of correct responses and reaction times reduction were greater in the Experiment 2 as compared to Experiment 1, suggesting that in the present experimental conditions, identification of the place for stimulus presentation is prompter as compared to the difference in the frequency of the target stimuli. Together these results show that engagement and maintenance of attentional resources along time vary as a function of the peripheral and simbolic nature of the target stimuli. The frequency of target stimuli presented after a variable sequence of non-informative stimuli also interferes in performance of the subject
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Göhringer, Frederic [Verfasser], and Thomas [Akademischer Betreuer] Schenk. "To what extent are functions of the perceptual and the motor system separable? : an investigation using dual-tasking, the Garner paradigm, and the visual threshold of size discrimination / Frederic Göhringer ; Betreuer: Thomas Schenk." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/122827066X/34.
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Araújo, Lucas Delfino. "Transferência de Função no Controle de Respostas Verbais e Perceptuais: Uma Questão de Procedimento." Pontifícia Universidade Católica de Goiás, 2015. http://localhost:8080/tede/handle/tede/1903.
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Previous issue date: 2015-03-13The aim of this study was to evaluate the effect of different procedures on the transfer function between perceptual and verbal stimuli. Three experiments were conducted with 10 participants each, of both sex and university. In Experiment 1 was performed a conditional discrimination procedure using Matching-to-Smple having a stimulus as a model and three as a comparison. A set A was composed of three perceptual stimuli (pictures), a joint B consisted of three words without meaning and set C consisted of three words with meaning. Training was made between set B and set C then set A to set B (Group 1) and inverse training (group 2). The Experiment 2 was similar to Experiment 1, but comparisons were made gradually over the first comparison blocks to complete 3 comparisons and all followed the Group s training sequence 1 Experiment 1. In Experiment 3 was made a training with presentation of stimuli verbal (sentences) and a conditional discrimination training between meaningless words and words with meaning. Data from the three procedures indicate that there is transfer function between words with meaning, figures and meaningless words, and 40% of the participants in Experiment 1 were obtained transfer function for the three meaningless words, 80% of the participant in Experiment 2 achieved transfer function for the three meaningless words and 100% of the participants in Experiment 3 obtained transfer function for the three meaningless words.
O objetivo do presente trabalho foi verificar o efeito de diferentes procedimentos sobre a transferência de função entre estímulos perceptuais e verbais. Foram realizados três experimentos contendo 10 participantes cada, de ambos os sexos e universitários. No Experimento 1 foi realizado um procedimento de discriminação condicional utilizando Matching-to-Smple tendo um estímulo como modelo e três como comparação. Um conjunto A compunha-se de três estímulos perceptuais (figuras), um Conjunto B compunha-se de três palavras sem sentido e um Conjunto C compunha-se de três palavras com sentido. Foi feito treino entre Conjunto B e Conjunto C e depois de Conjunto A com Conjunto B (Grupo 1) e treino inverso (Grupo 2). No Experimento 2 foi semelhante ao Experimento 1, mas as comparações eram apresentadas gradualmente durante os blocos de 1 comparação até completar 3 comparações e todos seguiram a sequência de treino do Grupo 1 do Experimento 1. No Experimento 3 foi feito um treino com apresentação de estímulos verbais (sentenças) e um treino de discriminação condicional entre palavras sem sentido e palavras com sentido. Os dados dos três procedimentos indicam que há transferência de função entre palavras com sentido, figuras e palavras sem sentido, sendo que 40% dos participantes do Experimento 1 obtiveram transferência função para as três palavras sem sentido, 80% dos participantes do Experimento 2 obtiveram transferência de função para as três palavras sem sentido e 100% dos participantes do Experimento 3 obtiveram transferência de função para as três palavras sem sentido.
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Ghosh, Natasha. "Discrimination of perceptually similar natural categories by pigeons." Thesis, University of Exeter, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392783.
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Fagelson, Marc A., and C. A. Champlin. "Auditory Filters Measured at Neighboring Center Frequencies." Digital Commons @ East Tennessee State University, 1997. https://dc.etsu.edu/etsu-works/1581.
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Auditory filters were derived in 20 normal-hearing human listeners at center frequencies (CFs) of 913, 1095, 3651, and 4382 Hz using the roex (p,r) method. Comparisons were made between slopes of the filters' skirts at the neighboring CFs with filter output levels of 45 and 70 dB. The same comparisons were made with regard to filter equivalent rectangular bandwidth (ERB). In the 1000-Hz region, the low-frequency slopes (Pl) of filters centered at 913 and 1095 Hz were significantly correlated at both stimulus levels, while the high-frequency slopes (Pu) were similar only at the high test level. In the 4000-Hz region, for sinusoids of 3651 and 4382 Hz, the level effect was clearer as both Pu and Pl values diverged at the low level but were related at high levels. The ERBs centered at the same CFs displayed a similar level dependence. At the stimulus level most likely to be affected by an active feedback mechanism, auditory filters centered at nearly the same frequency displayed quite distinct frequency selectivity, and this trend was stronger in the 4000-Hz region than the 1000-Hz region. The findings suggest that a saturating, active cochlear mechanism may not be distributed evenly, or contribute to peripheral tuning with equal effectiveness throughout the length of the partition.
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Hadley, Hillary R. "Does Early Perceptual Experience Influence Later Perceptual and Neural Discrimination in Children?" 2013. https://scholarworks.umass.edu/theses/1010.
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In infancy, the ability to tell the difference between two faces within a category (e.g., species, race) that is infrequently experienced declines from 6 to 9 months of age (Kelly et al., 2009, 2007; Pascalis et al., 2005; Pascalis, de Haan, & Nelson, 2002; Scott & Monesson, 2009). This decline in the ability to distinguish faces is known as "perceptual narrowing" and has recently been found to be absent when infants are given experience matching a face with an individual-level proper name between 6 to 9 months of age (Scott & Monesson, 2009). Additionally, individual-level experience between 6 and 9 months of age has led to neural changes at 9 months of age (Scott & Monesson, 2010). It is currently unclear whether brief, early experience between 6 and 9 months leads to sustained behavioral advantages and lasting neural changes. In order to answer these questions, the current study recruited and tested children who previously participated in a face training study when they were infants (Scott & Monesson, 2009, 2010). Findings revealed that individual-level experience with faces during the first year of life: 1) resulted in faster reaction time for faces outside of the trained category, and 2) led to more adult-like neural representations of faces outside of the trained category 3-4 years later. These results suggest that experience with individual-level learning in the first year of life is generalized to visually similar, but environmentally relevant face categories.
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Sezikeye, François Xavier. "Mechanisms of texture discrimination : what is behind the perceptual performance asymmetry?" Thesis, 2005. http://spectrum.library.concordia.ca/8332/1/MR04323.pdf.
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A patch of texture A embedded in a background of texture B, is sometimes detected more easily than a same size patch of texture B embedded in a background of texture A. This phenomenon is called texture discrimination asymmetry. The perceptual texture performance asymmetry was investigated by manipulating the orientation variation of lines, the gradual change of L and + micropatterns and the frequency change in filtered random noise. Variability was shown to be a large contribution in the asymmetry, and a model using quadratic forms and signal detection theory was in qualitative agreement. An experiment with randomly oriented and fixed orientation micropatterns also showed the important role played by variability in asymmetry. The enclosing circles of micropatterns had a contribution lower than variability in asymmetry. The foreground-background area ratio and the textons were important in establishing the way of the asymmetry: classic cases of asymmetry in micropatterns were reversed by manipulating those characteristics. Discrimination, therefore asymmetry, was shown to depend on both edge and region mechanisms.
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Hagen, Simen. "The influence of real-world object expertise on visual discrimination mechanisms." Thesis, 2017. https://dspace.library.uvic.ca//handle/1828/8942.
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Object experts quickly and accurately discriminate objects within their domain of expertise. Although expert recognition has been extensively studied both at the behavioral- and neural-levels in both real-world and laboratory trained experts, we know little about the visual features and perceptual strategies that the expert learns to use in order to make fast and accurate recognition judgments. Thus, the aim of this work was to identify the visual features (e.g., color, form, motion) and perceptual strategies (e.g., fixation pattern) that real-world experts employ to recognize objects from their domain of expertise. Experiments 1 to 3 used psychophysical methods to test the role of color, form (spatial frequencies), and motion, respectively, in expert object recognition. Experiment 1 showed that although both experts and novices relied on color to recognize birds at the family level, analysis of the response time distribution revealed that color facilitated expert performance in the fastest and slowest trials whereas color only helped the novices in the slower trials. Experiment 2 showed that both experts and novices were more accurate when bird images contained the internal information represented by a middle range of SFs, described by a quadratic function. However, the experts, but not the novices, showed a similar quadratic relationship between response times and SF range. Experiment 3 showed that, contrary to our prediction, both groups were equally sensitivity to global bird motion. Experiment 4, which tested the perceptual stategies of expert recognition in a gaze-contingent eye-tracking paradigm, showed that only in the fastest trials did experts use a wider range of vision. Experiment 5, which examined the neural representations of categories within the expert domain, suggested that the mechanisms that represents within-categories of faces also represented within-categories from the domain of expertise, but not the novice domain. Collectively, these studies suggest that expertise influence visual discrimination mechanisms such that they become more sensitive to the visual dimensions upon which the expert domains are discriminated.Graduate
2018-12-12
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OuYang, Kuo-An, and 歐陽國安. "A Study on Effect of Graphic User Interface designs on Discrimination Ability-Applying Perceptual Grouping Theory." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/65569858775780646129.
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碩士義守大學
資訊管理學系碩士班
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A Study on the Effect of Graphic User Interface designs on Discrimination Ability –Applying Perceptual Grouping Theory Abstract Graphic user interface (GUI ) for information system have become the mainst- ream of interface design in recent years. With the application of GUI getting more and more wide and the screen more and more complicated, users tend to have uneasy or tired feelings after long time use and the ability of discrimination decrease. This resea- rch explores, by using rules of Perceptual Grouping Theory, the way of screen designs that helps users to efficiently recognize the targets on GUI. The experiments designed in this research are based on the grouping rules such as “Law of Similarity”, “Law of Proximity”, “Law of Closed Forms” and “Law of Figure and Ground”. The response times of searching target are recorded as measure of discrimination ability for further analysis. We adopt statistical analysis and hypothesis testing on the experimental results and propose the following conclusions: 1) The colors, forms, sizes and positions of the interface component significantly influence discrimination ability; 2) The distances between components significantly influence discrimination ability; 3) Using the techniques of grouping or splitting on the components such as GroupBox, RadioGroup and Panel can promote the ability of discrimination significantly. Key word：Graphic user interface , Perceptual Grouping Theory, discrimination.
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Reed, Amanda Christine. "Plasticity in the auditory cortex and changes in perceptual discrimination after nucleus basalis stimulation in rats /." 2008. http://proquest.umi.com/pqdweb?did=1597612641&sid=6&Fmt=2&clientId=10361&RQT=309&VName=PQD.
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Adhikari, Bhim M. "Oscillatory Network Activity in Brain Functions and Dysfunctions." 2014. http://scholarworks.gsu.edu/phy_astr_diss/67.
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Recent experimental studies point to the notion that the brain is a complex dynamical system whose behaviors relating to brain functions and dysfunctions can be described by the physics of network phenomena. The brain consists of anatomical axonal connections among neurons and neuronal populations in various spatial scales. Neuronal interactions and synchrony of neuronal oscillations are central to normal brain functions. Breakdowns in interactions and modifications in synchronization behaviors are usual hallmarks of brain dysfunctions. Here, in this dissertation for PhD degree in physics, we report discoveries of brain oscillatory network activity from two separate studies. These studies investigated the large-scale brain activity during tactile perceptual decision-making and epileptic seizures.
In the perceptual decision-making study, using scalp electroencephalography (EEG) recordings of brain potentials, we investigated how oscillatory activity functionally organizes different neocortical regions as a network during a tactile discrimination task. While undergoing EEG recordings, blindfolded healthy participants felt a linear three-dot array presented electromechanically, under computer control, and reported whether the central dot was offset to the left or right. Based on the current dipole modeling in the brain, we found that the source-level peak activity appeared in the left primary somatosensory cortex (SI), right lateral occipital complex (LOC), right posterior intraparietal sulcus (pIPS) and finally left dorsolateral prefrontal cortex (dlPFC) at 45, 130, 160 and 175 ms respectively. Spectral interdependency analysis showed that fine tactile discrimination is mediated by distinct but overlapping ~15 Hz beta and ~80 Hz gamma band large-scale oscillatory networks. The beta-network that included all four nodes was dominantly feedforward, similar to the propagation of peak cortical activity, implying its role in accumulating and maintaining relevant sensory information and mapping to action. The gamma-network activity, occurring in a recurrent loop linked SI, pIPS and dlPFC, likely carrying out attentional selection of task-relevant sensory signals. Behavioral measure of task performance was correlated with the network activity in both bands.
In the study of epileptic seizures, we investigated high-frequency (> 50 Hz) oscillatory network activity from intracranial EEG (IEEG) recordings of patients who were the candidates for epilepsy surgery. The traditional approach of identifying brain regions for epilepsy surgery usually referred as seizure onset zones (SOZs) has not always produced clarity on SOZs. Here, we investigated directed network activity in the frequency domain and found that the high frequency (>80 Hz) network activities occur before the onset of any visible ictal activity, andcausal relationships involve the recording electrodes where clinically identifiable seizures later develop. These findings suggest that high-frequency network activities and their causal relationships can assist in precise delineation of SOZs for surgical resection.
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Klapwijk, Jonathan Menno. "A validation of the Visual Perceptual Aspects Test using a bifactor exploratory structural equation modelling approach." Diss., 2018. http://hdl.handle.net/10500/25693.
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Visual perception is a psychological construct that describes the awareness of visual sensations and arise from the interactions of the individual or observer in the external environment together with the physiology of the observer’s visual system. A variety of theories of the development of visual perception have led to the development of different psychometric measures aimed at quantifying the cognitive construct. The Visual Perceptual Aspects Test was developed by Clutten (2009) to measure nine different constructs of visual perception. The original VPAT was validated using content and construct validity based on a Western Cape sample. However, to the researcher’s knowledge, a factor analysis had not yet been conducted on the VPAT to determine the factor validity of the test. Furthermore, no measures of validity or reliability had been conducted on the VPAT using a sample outside of the Western Cape. The aim of this research is to validate the hypothesised nine factor structure of the Visual Perceptual Aspects Test, using a confirmatory factor analysis, exploratory structural equation model, a bifactor confirmatory factor analysis and a bifactor exploratory structural equation model. The results of the analysis showed marginal model fit of the VPAT with the sample data, with sufficient levels of reliability for certain sub-tests. However, the VPAT did not meet significant levels of validity or reliability of the proposed model structure of the VPAT for the sample group of learners based in the Eastern Cape.Psychology
M.A. (Research Psychology)
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Vavassis, Angela. "Perceptual learning specificity to the trained context of stimulus display durations in difficult visual discriminations." Thesis, 2007. http://spectrum.library.concordia.ca/975571/1/MR34654.pdf.
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Compelling evidence stemming from past research suggests that a wide variety of visual search tasks can undergo perceptual learning. Such learning is typically characterized by a marked improvement in the speed and accuracy of target detection or identification by observers, as a result of repeated practice with the visual search task at hand. For difficult visual discriminations, the improvement in visual search performance associated with perceptual learning has been shown to be specific to the training context. Such contexts include, but are not limited to, the trained target stimuli and their trained retinal positions within the visual field. The current compilation of psychophysical experiments aimed to investigate an aspect of perceptual learning specificity in difficult visual discriminations previously unreported in the relevant literature. These experiments assessed whether perceptual learning for difficult visual discriminations is specific to the trained context of stimulus display durations in which such discriminations are embedded. With training, a significant improvement in performance for trials with a 50-millisecond stimulus display duration (difficult discriminations) resulted when such trials were embedded within sessions containing a variety of longer stimulus display durations (easier discriminations). However, this improvement was lost when difficult trials were no longer embedded within the context of easier trials. These findings may supplement our current knowledge regarding the perceptual plasticity of the visual system.
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Carland, Matthew A. "A theoretical and experimental dissociation of two models of decision‐making." Thèse, 2014. http://hdl.handle.net/1866/12038.
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La prise de décision est un processus computationnel fondamental dans de nombreux aspects du comportement animal. Le modèle le plus souvent rencontré dans les études portant sur la prise de décision est appelé modèle de diffusion. Depuis longtemps, il explique une grande variété de données comportementales et neurophysiologiques dans ce domaine. Cependant, un autre modèle, le modèle d’urgence, explique tout aussi bien ces mêmes données et ce de façon parcimonieuse et davantage encrée sur la théorie. Dans ce travail, nous aborderons tout d’abord les origines et le développement du modèle de diffusion et nous verrons comment il a été établi en tant que cadre de travail pour l’interprétation de la plupart des données expérimentales liées à la prise de décision. Ce faisant, nous relèveront ses points forts afin de le comparer ensuite de manière objective et rigoureuse à des modèles alternatifs. Nous réexaminerons un nombre d’assomptions implicites et explicites faites par ce modèle et nous mettrons alors l’accent sur certains de ses défauts. Cette analyse servira de cadre à notre introduction et notre discussion du modèle d’urgence. Enfin, nous présenterons une expérience dont la méthodologie permet de dissocier les deux modèles, et dont les résultats illustrent les limites empiriques et théoriques du modèle de diffusion et démontrent en revanche clairement la validité du modèle d'urgence. Nous terminerons en discutant l'apport potentiel du modèle d'urgence pour l'étude de certaines pathologies cérébrales, en mettant l'accent sur de nouvelles perspectives de recherche.Decision‐making is a computational process of fundamental importance to many aspects of animal behavior. The prevailing model in the experimental study of decision‐making is the drift‐diffusion model, which has a long history and accounts for a broad range of behavioral and neurophysiological data. However, an alternative model – called the urgency‐gating model – has been offered which can account equally well for much of the same data in a more parsimonious and theoretically‐sound manner. In what follows, we will first trace the origins and development of the DDM, as well as give a brief overview of the manner in which it has supplied an explanatory framework for a large number of behavioral and physiological studies in the domain of decision‐making. In so doing, we will attempt to build a strong and clear case for its strengths so that it can be fairly and rigorously compared to potential alternative models. We will then re‐examine a number of the implicit and explicit theoretical assumptions made by the drift‐diffusion model, as well as highlight some of its empirical shortcomings. This analysis will serve as the contextual backdrop for our introduction and discussion of the urgency‐gating model. Finally, we present a novel experiment, the methodological design of which uniquely affords a decisive empirical dissociation of the models, the results of which illustrate the empirical and theoretical shortcomings of the drift‐diffusion model and instead offer clear support for the urgency‐gating model. We finish by discussing the potential for the urgency gating model to shed light on a number of clinical disorders, highlighting a number of future directions for research.