Pauline Schaller¹ (), Steve Katembu², Sotaro Taniguchi³, Junhao Jiang³, Akira Sarodo³, Charles Obadiah Kimamo², Katsumi Watanabe³, Anne-Raphaëlle Richoz¹, Roberto Caldara¹; ¹Eye and Brain Mapping Laboratory (iBMLab), Department of Psychology, University of Fribourg, Fribourg, Switzerland, ²Department of Psychology, University of Nairobi, Nairobi, Republic of Kenya, ³Faculty of Science and Engineering, Waseda University, Tokyo, Japan

Understanding how social identity influences face perception remains a fundamental challenge in vision science. Prior research reveals consistent perceptual advantages for categorizing other-race faces, the so-called Other-Race Categorization Advantage (ORCA). However, the mechanisms underlying this effect remain contested, particularly regarding the interplay between socio-cognitive factors and perceptual expertise. Virtual Reality (VR) technology offers a novel approach by temporarily manipulating perceived racial identity through avatar embodiment. We conducted a large-scale, cross-cultural study involving over 250 participants from Kenya, Japan, and Switzerland. Participants completed two face race categorization tasks: one using 100% race-typical faces and another using morphed stimuli varying continuously along a race composition continuum. Participants underwent embodiment in either same-race (SR) or other-race (OR) avatars matched to their sex, engaging in three interactive embodiment-enhancing activities involving visuo-auditory and visuo-tactile feedback, in a VR environment replicating the real laboratory. Following embodiment, participants repeated the categorization tasks with new face stimuli. Our data showed that OR embodiment did not reduce the ORCA in coarse categorization, suggesting the speed advantage for processing OR faces remains resilient to transient social identity shifts. However, OR embodiment reliably modulated fine-grained race perception: participants embodied in OR avatars were significantly more likely to classify ambiguous morphed faces as SR post-embodiment compared to pre-embodiment, indexed by a substantial positive shift in the Point of Subjective Equality relative to SR-embodied controls. These findings demonstrate that shifts in perceived social identity, can modulate perceptual categorization. These novel insights into the mechanisms underlying face race perception across diverse populations validate VR embodiment as a powerful tool for experimentally manipulating social affiliation and open new theoretical and methodological pathways for understanding the psychological bases of perception. By enabling controlled changes in perceived group membership, VR provides a promising foundation for intervention studies designed to overcome other-race effects and reshape face processing biases.

Acknowledgements: This work was supported by a grant from the Swiss National Science Foundation [n◦100019_189018] awarded to Roberto Caldara.