Thesis advisor: Stefano Anzellotti / There has been much debate over how the functional organization of vision develops. Contemporary theories that are inspired by analyzing neural data with machine learning models have led to new insights in understanding brain organization. Given the evolutionary importance of face perception and the specialized mechanisms that have evolved to support evaluating it, examining faces offers a unique way to study a dedicated mechanism that shares much of its organization in ventral and lateral neural pathways with other social stimuli, and provide insight into a more general principle of the organization of social perception. According to a classical view of face perception (Bruce and Young, 1986; Haxby, Hoffman, and Gobbini, 2000), face identity and facial expression recognition are performed by separate neural substrates (ventral and lateral temporal face-selective regions, respectively). However, recent studies challenge this view, showing that expression valence can also be decoded from ventral regions (Skerry and Saxe, 2014; Li, Richardson, and Ghuman, 2019) and identity from lateral regions (Anzellotti and Caramazza, 2017). These recent findings have inspired the formulation of an alternative hypothesis. From a computational perspective, it may be possible to process face identity and facial expression jointly by disentangling information for the two properties. This hypothesis was tested using deep convolutional neural network (DCNN) models as a proof of principle. Subsequently, this is then followed by evaluating the representational content of static face stimuli within ventral and lateral temporal face- selective regions using intracranial electroencephalography (iEEG). This is then extended to investigating the representation content of dynamic faces within these regions using functional magnetic resonance imaging (fMRI). The results reported here as well as the reviewed literature may help to support the reevaluation of the roles the ventral and lateral temporal neural pathways play in processing socially-relevant stimuli. / Thesis (PhD) — Boston College, 2024. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Psychology and Neuroscience.

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Distinctiveness plays an important role in the recognition of faces, i.e., a distinctive face is usually easier to remember than a typical face in a recognition task. This distinctiveness effect explains why caricatures are recognized faster and more accurately than unexaggerated (i.e., veridical) faces. Furthermore, using caricatures during training can facilitate recognition of a person’s face at a later time. The objective of this thesis is to determine the extent to which photorealistic computer-generated caricatures may be used in training tools to improve recognition of faces by humans. To pursue this objective, we developed a caricaturization procedure for three-dimensional (3D) face models, and characterized face recognition performance (by humans) through a series of perceptual studies. The first study focused on 3D shape information without texture. Namely, we tested whether exposure to caricatures during an initial familiarization phase would aid in the recognition of their veridical counterparts at a later time. We examined whether this effect would emerge with frontal rather than three-quarter views, after very brief exposure to caricatures during the learning phase and after modest rotations of faces during the recognition phase. Results indicate that, even under these difficult training conditions, people are more accurate at recognizing unaltered faces if they are first familiarized with caricatures of the faces, rather than with the unaltered faces. These preliminary findings support the use of caricatures in new training methods to improve face recognition. In the second study, we incorporated texture into our 3D models, which allowed us to generate photorealistic renderings. In this study, we sought to determine the extent to which familiarization with caricaturized faces could also be used to reduce other-race effects (e.g., the phenomenon whereby faces from other races appear less distinct than faces from our own race). Using an old/new face recognition paradigm, Caucasian participants were first familiarized with a set of faces from multiple races, and then asked to recognize those faces among a set of confounders. Participants who were familiarized with and then asked to recognize veridical versions of the faces showed a significant other-race effect on Indian faces. In contrast, participants who were familiarized with caricaturized versions of the same faces, and then asked to recognize their veridical versions, showed no other-race effects on Indian faces. This result suggests that caricaturization may be used to help individuals focus their attention to features that are useful for recognition of other-race faces. The third and final experiment investigated the practical application of our earlier results. Since 3D facial scans are not generally available, here we also sought to determine whether 3D reconstructions from 2D frontal images could be used for the same purpose. Using the same old/new face recognition paradigm, participants who were familiarized with reconstructed faces and then asked to recognize the ground truth versions of the faces showed a significant reduction in performance compared to the previous study. In addition, participants who were familiarized with caricatures of reconstructed versions, and then asked to recognize their corresponding ground truth versions, showed a larger reduction in performance. Our results suggest that, despite the high level of photographic realism achieved by current 3D facial reconstruction methods, additional research is needed in order to reduce reconstruction errors and capture the distinctive facial traits of an individual. These results are critical for the development of training tools based on computer-generated photorealistic caricatures from “mug shot” images.

Thesis (Ph. D.)--University of California, San Diego, 2002. / Vita. Includes bibliographical references (leaves 158-169).

Thesis (M.F.A.)--University of Central Florida, 2009. / Adviser: Carla Poindexter. Includes bibliographical references (p. 31).

Thesis (M.S.)--Florida State University, 2003. / Advisor: Dr. Gordon Erlebacher, Florida State University, College of Arts and Sciences, Dept. of Computer Science. Title and description from dissertation home page (viewed Apr. 06, 2004). Includes bibliographical references.

Thesis (M.A.)--York University, 1998. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 49-52). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ39194.

Thesis (Ph.D.)--Kent State University, 2008. / Title from PDF t.p. (viewed Nov. 10, 2009). Advisor: Nancy Docherty. Keywords: schizophrenia, paranoia, emotion recognition, posed expressions, spontaneous expressions, cognition. Includes bibliographical references (p. 122-144).

Thesis (M.A.)--York University, 2008. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 72-94). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR45951

Much of the previous research on systematic variation in social judgements has focused on attractiveness judgements and factors that are related to inter-sexual competition (reviewed in Chapter 1). By contrast, there has been relatively little work on the extent to which factors that may be more closely related to intra-sexual competition, such as the outcomes of aggressive conflict with own-sex individuals and competition for resources, may have shaped perceptions of potential rivals. Correlational studies showed that indices of men’s (Chapter 2) and women’s (Chapter 4) own dominance were negatively correlated with the extent to which they perceived masculine own-sex individuals to be more dominant than feminine own-sex individuals. These findings suggest that those individuals who are likely to incur more substantial costs if they underestimate the dominance of potential rivals may find cues of others’ dominance (i.e., masculine characteristics) to be particularly salient. Further evidence for this proposal came from priming experiments in which men who were primed with scenarios in which they lost confrontations were more likely to ascribe high dominance, but not trustworthiness, to masculine men’s faces than were men who were primed with scenarios in which they won confrontations (Chapter 3). Further priming experiments suggested that priming women with cues to the sex ratio of the local population (Chapter 5) or priming women’s concerns about resources versus pathogens (Chapter 6) altered the salience of facial cues of others’ attractiveness and dominance. While previous research on systematic variation in social perception has tended to focus on attractiveness judgements and factors related to inter-sexual competition, the findings reported in this thesis highlight the potential importance of dominance perceptions and factors related to intra-sexual competition. Directions for future research, such as establishing whether dominance perceptions predict real world social outcomes, are then discussed (Chapter 7).