UNIVERSITY GRADUATE SCHOOL BULLETIN ANNOUNCEMENT

Florida International University
University Graduate School

Doctoral Dissertation Defense

Abstract

Context Specific Encoding of Face Shape Features Used for Recognition of Face Identity and Expression

by

Emily Renae Martin

Accurate recognition of facial identity and emotional expression is critical for effective social interaction. Therefore, a central goal in face research is to determine how facial shape information is represented in behavior and in the brain, and how context modulates these representations. To explore how rigorous quantitative methodologies can be used to study face perception, I review available generative face stimulus tools and statistical models. I then apply a three-dimensional face modeling toolbox to generate precisely controlled stimuli and recover the anatomically interpretable facial features that drive identity and emotional expression representations. Using reverse correlation to estimate perceptual representations, permutation tests revealed the information used during identity and expression recognition is highly flexible and context specific. That is, information sampled during identity recognition varied with expression, and vice-versa. Results also revealed that recognition of identity and expression depended on subtle changes in morphological shape distributed across the face and effects were observed in regions smaller than what was found in traditional studies. To assess how faces are encoded in the brain, I conducted an EEG experiment and used ridge regression to determine (1) which identity features predicted neural activity at different time points, (2) how these feature associations dynamically evolved, and (3) whether they were modulated by emotional expression. While few individual features were significant at specific time points, clusters of features showed systematic temporal changes. Significant features across both emotional expressions and across several regions of interest were associated with task demands and occurred during early visual processing, indicating that attentional processes overrode higher-level identification processing. These results suggest context drives shape representations. Behaviorally, I found emotional expression systematically changed identity representations and vice-versa. However, within EEG data, feature encoding was limited and identity features correlated with task-relevant features were significant, while emotional expression context had no measurable effect. These findings imply that the visual system is sensitive both visual and attentional context and highlight the importance of using quantitative methodologies in further research.

Date: March 24, 2026  Department: Psychology

Time: 10:00 a.m.  Major Professor: Fabian Soto

Place: FIU MMC, Deuxième Maison (DM) 258

Zoom:https://fiu.zoom.us/j/83574509297?pwd=UZS0ZBrzKv79G49jBX4ImYbo21VbLn.1