Maleeha Chowdhury¹, Arianna Thoksakis¹, Edward Ester¹; ¹University of Reno, Nevada

Pareidolia is the phenomenon in which one perceives meaningful patterns in ambiguous stimuli. A specific example of this is face pareidolia, which involves the perception of faces in stimuli in which none exist. This act of false perception is a natural error of the face processing system and thus operates as a gateway to study the neural mechanisms of face processing. A significant component of face perception research is the N170 event-related potential (ERP), a face-selective scalp potential. While previous studies have examined the involvement of the N170 in the neural bases of pareidolia, evidence has been inconsistent and limited to small samples of neurodivergent groups. To contrast such limitations in our study, we asked human observers (N = 14) to passively view stimuli of illusory faces, matched nonface objects, and faces while monitoring for face-selective electroencephalography (EEG) signals over 9,216 trials. This large number of trials provides the important advantage of providing insight on an individual basis due to the large number of measurements per observer. The N170 effect was present in all stimuli, but was only significant in face trials. However, this result was inconsistent at the individual level. We observed a heterogeneity of the N170 effect, with differing amplitudes for illusory face stimuli across individuals. Together, these results suggest differing neural amplitudes for face, object, and illusory face stimuli. We are now following up on these results with a response-limited paradigm that will allow us to track the latency and amplitude of N170 signals in relation to response time. These results will be presented at the VSS 2025 meeting.

Acknowledgements: This work was funded by the National Science Foundation