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An exploratory study on the influence of the own-race bias on the serial position effect in facial recognitionGouws, Erik Petrus 27 September 2010 (has links)
The research aimed to explore the potential occurrence of the serial position effect and the own-race bias in facial recognition, and to explore whether these two socio-cognitive psychological phenomena had any influence on each other. Specifically, the researcher suggested that other-race facial recognition will show diminished U-type serial position curves in comparison to own-race facial recognition U-type serial position curves. This was done through a quasi-experimental design, testing 48 participants from an environmental consulting and ground engineering firm in Midrand, Johannesburg. Twelve (12) sets of slides showing either 5 black or 5 white faces were presented to participants, the sequence of faces was randomised and then displayed again to participants. Participants had to identify the original position in which the face was displayed (forcing a serial reconstruction task). Results yielded a U-type serial position curves for overall recognition, with a statistically significant effect for own-race bias effect. Specific interactions indicated that recognition for own-race facial stimuli exhibit clear serial position effect trends, whilst recognition of other-race facial stimuli recognition show increased recognition for the first, middle and last faces in a set. The researcher suggests that the results within this study could be attributed to the effect of an attentional primacy gradient within the Serial Information Processing model. However, further studies are required to eliminate numerous other confounding factors which may have played a role in the study. The results of this research have implications for the judicial system, in which false eyewitness identifications have profound consequences. / Dissertation (MA)--University of Pretoria, 2010. / Psychology / unrestricted
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Effect of the Muslim headscarf on face perception : a series of psychological experiments looking at how the Muslim headscarf influences the perception of (South Asian) facesToseeb, Mohammed Umar January 2012 (has links)
The Muslim headscarf conceals the hair and other external features of a face. For this reason it may have implications for the recognition of such faces. The experiments reported in this thesis aimed to investigate anecdotal reports, which suggested that headscarf wearing females are more difficult to recognise. This was done by employing a series of experiments which involved a yes/no recognition task. The stimuli that were used were images of South Asian females who were photographed wearing a Muslim headscarf (HS), with their own hair visible (H), and a third set of stimuli were produced in which their external features were cropped (CR). Most importantly, participants either took part in the condition in which the state of the external features remained the same between the learning and test stage (Same) or the condition in which they were switched between the two stages (Switch). In one experiment participants completed a Social Contact Questionnaire. Surprisingly, in the Same condition, there was no difference in the recognition rates of faces that were presented with hair, with headscarf, or cropped faces. However, participants in the Switch condition performed significantly worse than those in the Same condition. It was also found that there was no difference in the % of fixations to the external features between the Same and Switch condition, which implied that the drop in performance between the two conditions was not mediated by eye-movements. These results suggest that the internal and external features of a face are processed interactively and, although the external features were not fixated on, a manipulation to them caused a drop in performance. This was confirmed in a separate experiment in which participants were unable to ignore the external features when they were asked to judge the similarity of the internal features of pairs of faces. Pairs of headscarf faces were rated as being more similar compared to pairs of faces with hair. Finally, for one group of participants it was found that contact with headscarf-wearing females was positively correlated with the recognition of headscarf-wearing faces. It was concluded that the headscarf per se did not impair face recognition and that there is enough information in the internal features of a face for optimal recognition, however, performance was disrupted when the presence or absence of the headscarf was manipulated.
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Effect of the Muslim Headscarf on Face Perception. A series of psychological experiments looking at how the Muslim headscarf influences the perception of (South Asian) faces.Toseeb, Mohammed U. January 2012 (has links)
The Muslim headscarf conceals the hair and other external features of a face. For this reason
it may have implications for the recognition of such faces. The experiments reported in this
thesis aimed to investigate anecdotal reports, which suggested that headscarf wearing females
are more difficult to recognise. This was done by employing a series of experiments which
involved a yes/no recognition task. The stimuli that were used were images of South Asian
females who were photographed wearing a Muslim headscarf (HS), with their own hair
visible (H), and a third set of stimuli were produced in which their external features were
cropped (CR). Most importantly, participants either took part in the condition in which the
state of the external features remained the same between the learning and test stage (Same) or
the condition in which they were switched between the two stages (Switch). In one
experiment participants completed a Social Contact Questionnaire. Surprisingly, in the Same
condition, there was no difference in the recognition rates of faces that were presented with
hair, with headscarf, or cropped faces. However, participants in the Switch condition
performed significantly worse than those in the Same condition. It was also found that there
was no difference in the % of fixations to the external features between the Same and Switch
condition, which implied that the drop in performance between the two conditions was not
mediated by eye-movements. These results suggest that the internal and external features of
a face are processed interactively and, although the external features were not fixated on, a
manipulation to them caused a drop in performance. This was confirmed in a separate
experiment in which participants were unable to ignore the external features when they were
asked to judge the similarity of the internal features of pairs of faces. Pairs of headscarf faces
were rated as being more similar compared to pairs of faces with hair. Finally, for one group
of participants it was found that contact with headscarf-wearing females was positively
correlated with the recognition of headscarf-wearing faces. It was concluded that the
headscarf per se did not impair face recognition and that there is enough information in the
internal features of a face for optimal recognition, however, performance was disrupted when
the presence or absence of the headscarf was manipulated.
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Ansiktsigenkänning : Holistisk och analytisk bearbetning vid ansiktsigenkänning av den egna etniska gruppen jämfört med andra etniska grupper / Ethnic bias in face recognition : are own-race faces processed more holistically?Persson, Matilda January 2010 (has links)
Abstract (Svenska) Den här undersökningen försöker ta reda på om orsaken till att människor bättre minns ansikten av sin egen etnicitet än ansikten med annan etnisk bakgrund ligger i mer holistisk än analytisk inkodning. Det testades även om kända och okända ansikten inkodas holistiskt eller analytiskt. Sammanlagt 51 personer deltog i undersökningen. Hälften av stimulusmaterialet var ljushyade (amerikaner av europeiskt ursprung) och hälften var mörkhyade (amerikaner av afrikanskt ursprung). 1/3 av stimulusmaterialet var bilder av mörka och ljusa kända personer. Uppgiften var att försöka känna igen bilderna då de visades på nytt med en förvrängning som skulle gynna antingen holistisk eller analytisk bearbetning. Resultaten visade att kända ansikten inkodades bättre än okända, och att skillnaden var större för holistisk än analytisk bearbetning. Skillnaden mellan ljusa och mörka ansikten gick i samma riktning, men var inte signifikant. / Abstract (English) The purpose of this study was to examine if the reason for Own Race Bias (ORB) – The fact that humans remember faces of their own ethnicity better than faces with another ethnic background/history – lies in the encoding mechanism. It also examined if celebrity faces were more holistically, and non-celebrity faces more analytically, encoded. Half of the stimulus material consisted of Caucasian Americans, and the other half of African Americans. One third of the faces belonged to celebrities. The task for the 51 participants was to recognize the faces. The results showed that celebrity faces were more often recognized than non-celebrity faces, and the difference was greater in holistic processing than in analytic. The difference between Caucasian and African faces showed the same tendency, but was not significant.
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An Investigation into the Performance of Ethnicity Verification Between Humans and Machine Learning AlgorithmsJilani, Shelina K. January 2020 (has links)
There has been a significant increase in the interest for the task of classifying
demographic profiles i.e. race and ethnicity. Ethnicity is a significant human
characteristic and applying facial image data for the discrimination of ethnicity is
integral to face-related biometric systems. Given the diversity in the application
of ethnicity-specific information such as face recognition and iris recognition, and
the availability of image datasets for more commonly available human
populations, i.e. Caucasian, African-American, Asians, and South-Asian Indians.
A gap has been identified for the development of a system which analyses the
full-face and its individual feature-components (eyes, nose and mouth), for the
Pakistani ethnic group. An efficient system is proposed for the verification of the
Pakistani ethnicity, which incorporates a two-tier (computer vs human) approach.
Firstly, hand-crafted features were used to ascertain the descriptive nature of a
frontal-image and facial profile, for the Pakistani ethnicity. A total of 26 facial
landmarks were selected (16 frontal and 10 for the profile) and by incorporating
2 models for redundant information removal, and a linear classifier for the binary
task. The experimental results concluded that the facial profile image of a
Pakistani face is distinct amongst other ethnicities. However, the methodology
consisted of limitations for example, low performance accuracy, the laborious
nature of manual data i.e. facial landmark, annotation, and the small facial image
dataset. To make the system more accurate and robust, Deep Learning models
are employed for ethnicity classification. Various state-of-the-art Deep models
are trained on a range of facial image conditions, i.e. full face and partial-face
images, plus standalone feature components such as the nose and mouth. Since
ethnicity is pertinent to the research, a novel facial image database entitled
Pakistani Face Database (PFDB), was created using a criterion-specific selection
process, to ensure assurance in each of the assigned class-memberships, i.e.
Pakistani and Non-Pakistani. Comparative analysis between 6 Deep Learning
models was carried out on augmented image datasets, and the analysis
demonstrates that Deep Learning yields better performance accuracy compared
to low-level features. The human phase of the ethnicity classification framework
tested the discrimination ability of novice Pakistani and Non-Pakistani
participants, using a computerised ethnicity task. The results suggest that
humans are better at discriminating between Pakistani and Non-Pakistani full
face images, relative to individual face-feature components (eyes, nose, mouth),
struggling the most with the nose, when making judgements of ethnicity. To
understand the effects of display conditions on ethnicity discrimination accuracy, two conditions were tested; (i) Two-Alternative Forced Choice (2-AFC) and (ii)
Single image procedure. The results concluded that participants perform
significantly better in trials where the target (Pakistani) image is shown alongside
a distractor (Non-Pakistani) image. To conclude the proposed framework,
directions for future study are suggested to advance the current understanding of
image based ethnicity verification. / Acumé Forensic
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