The distinctiveness of a face is a crucial factor for its ability to be discriminated, memorized, and identified correctly. In this thesis, we provided a contribution to face distinctiveness by examining the impact of socially relevant factors such as attractiveness, group and emotional expression on distinctiveness. We show that attractive faces are more similar to each other than unattractive faces, using female Caucasian faces and male faces of a Caucasian and heterogeneous Non-Caucasian group. We also show, using 3D face generated faces of photo-realistic quality, that attractive faces were closer to the prototype of only their specific group, and that hence typicality of attractive faces was group specific. Lastly, we show that assigning an emotional expression to a face that is evaluatively incongruent with its race makes it more psychologically distinctive, as revealed in perceptual discrimination and memory tasks.

The distinctiveness of a face is a crucial factor for its ability to be discriminated, memorized, and identified correctly. In this thesis, we provided a contribution to face distinctiveness by examining the impact of socially relevant factors such as attractiveness, group and emotional expression on distinctiveness. We show that attractive faces are more similar to each other than unattractive faces, using female Caucasian faces and male faces of a Caucasian and heterogeneous Non-Caucasian group. We also show, using 3D face generated faces of photo-realistic quality, that attractive faces were closer to the prototype of only their specific group, and that hence typicality of attractive faces was group specific. Lastly, we show that assigning an emotional expression to a face that is evaluatively incongruent with its race makes it more psychologically distinctive, as revealed in perceptual discrimination and memory tasks.

Schizophrenia is a psychiatric disorder characterized by social dysfunction. People with schizophrenia misinterpret social information and it is suggested that this difficulty may result from visual processing deficits. As faces are one of the most important sources of social information it is hypothesized that people suffering from the disorder have impairments in the visual face processing system. It is unclear which mechanism of the face processing system is impaired but two types of deficits are most often proposed: a deficit in face perception in general (i.e., processing of facial features as such) and a deficit in facial emotion processing (i.e., recognition of emotional facial expressions). Due to the contradictory evidence from behavioural, electrophysiological as well as neuroimaging studies offering support for the involvement of one or the other deficit in schizophrenia it is early to make any conclusive statements as to the nature and level of impairment. Further studies are needed for a better understanding of the key mechanism and abnormalities underlying social dysfunction in schizophrenia.

<p>Schizophrenia is a psychiatric disorder characterized by social dysfunction. People with schizophrenia misinterpret social information and it is suggested that this difficulty may result from visual processing deficits. As faces are one of the most important sources of social information it is hypothesized that people suffering from the disorder have impairments in the visual face processing system. It is unclear which mechanism of the face processing system is impaired but two types of deficits are most often proposed: a deficit in face perception in general (i.e., processing of facial features as such) and a deficit in facial emotion processing (i.e., recognition of emotional facial expressions). Due to the contradictory evidence from behavioural, electrophysiological as well as neuroimaging studies offering support for the involvement of one or the other deficit in schizophrenia it is early to make any conclusive statements as to the nature and level of impairment. Further studies are needed for a better understanding of the key mechanism and abnormalities underlying social dysfunction in schizophrenia.</p>

Thesis (Ph. D.)--University of Chicago, Dept. of Psychology, 2001. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of California, San Diego, 2010. / Title from first page of PDF file (viewed Feb. 18, 2010). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 100-110).

published_or_final_version / Psychology / Doctoral / Doctor of Philosophy

The central goal of the current thesis was to increase our understanding of how representations of individual faces are built from instances that vary. The prototype effect was used as a tool to probe the nature of our internal face representations. In face recognition, the prototype effect refers to the tendency to recognize, or find familiar, the average image of a face after having studied a series of similar face images. The experiments presented in this thesis investigated the modulating role of different variables on the prototype effect in face recognition. In the study phase, two or more different exemplars based on the same identity were presented. In the test phase, one of the seen exemplars, the unseen prototype, and an unseen exemplar of each studied identity were presented one at a time, and participants were asked to make a recognition judgement about the prior occurrence of either the exact image or the person’s face. Variants of each face identity were either unaltered images of real people’s faces, or they were created artificially by manipulating images of faces using several different techniques. All experiments using artificial variants produced strong prototype effects. The unseen prototype image was recognized more confidently than the actually studied images. This was true even when the variants were so similar that they were barely perceptually discriminable. Importantly, even when participants were given additional exposure to the studied exemplars, no weakening of the prototype effect was observed. Surprisingly, in the experiments using natural images of real people’s faces, no clear recognition advantage for the prototype image was observed. Results suggest that the prototype effect in face recognition might not be tapping an averaging mechanism that operates solely on variations within the same identity.

The goal of this dissertation was to better characterize the nature of infants’ visual preference for own-race faces, and to test two theories regarding its origin. Chapters I and II assessed whether the race bias in infancy could be attributed to an enhanced ability to discriminate familiar faces. Based on this account, infants' race preference should be more pronounced for female pairs of faces, and should only arise whenever different individuals are presented across trials. In Chapter I, White 3-month-old infants saw multiple male and female pairs differing in race. Looking times revealed a significant own-race preference only when male faces were presented. In Chapter II, participants viewed different photographs of the same two Black and White faces across 8 trials. Findings still revealed a robust own-race visual bias uniquely in male pairs. Collectively, these findings provide evidence against the notion that differences in face discriminability are responsible for babies’ racial preference. Moving to the question of origin, Chapter III tested the hypothesis that the male-specific own-race preference is rooted in an evolutionary threat response. Participants were presented with male and female pairs of own-and other-race faces displaying averted eye gaze, a cue meant to reduce threat. Findings were inconclusive as a looking time bias specifically toward White males yet again emerged. Finally, Chapter IV examined the idea that infants’ early visual preferences are shaped by experience. Three-month-olds were shown a video of an own- and other-race male addressing them in an infant-directed manner. Immediately following the video presentation participants’ visual preference for the two men depicted in the film was measured. Though the own-race preference persisted, looking times toward the Black male were significantly higher in comparison to a group of infants who received no exposure. These results are novel in revealing an own-race bias that is dependent on target gender, suggesting that gender is a stronger cue than race in guiding infants’ responses. Furthermore, though exposure did not attenuate overall preference, the findings point to the potential benefit of using such manipulations for changing bias in future research. / Psychology

Diamond and Carey (1986) identify sensitivity to second-order relational information (i.e., spatial relations among features such as the distance between eyes) as a vital part of achieving expertise with face processing. Previous research suggests that 5-month-olds are sensitive to second-order relational information when shown line drawings of faces in which this information has been manipulated to an exaggerated degree. The present series of experiments explored infants sensitivity to second-order relational information using photographs of real faces and with second-order manipulations that were within the normal range of human variability. A discrimination study conducted with adults provided additional evidence that the second-order manipulations were within the normal range. Five- and 7- month-olds exhibited sensitivity to changes in second-order relational information. Moreover, 5-months detected second-order changes in upright but not in inverted faces, thereby exhibiting an inversion effect that has been considered to be a hallmark of second-order relational processing in adulthood. These results suggest that infants as young as 5 months of age are sensitive to second-order relational changes that are within the normal range of human variability. They also indicate that at least rudimentary aspects of face-processing expertise are available early in life.