Abstract
Introduction: Previously we found that face recognition eye movement behavior varies substantially and reliably between individuals, with some preferring to fixate toward the eyes (Upper Lookers; UL) and others toward the nose (Lower Lookers; LL). These differences were found to be systematically related to individual differences in fixation-specific performance: ULs tend to do best when fixating the eyes, while LLs tend to do best when fixating the nose (Peterson & Eckstein, Psychological Science, 2013). The neural mechanisms mediating this relationship are unknown. Feasibly, these effects could arise from differences in domain-general (e.g., acuity/contrast sensitivity in the periphery), or in face-specific (e.g., fixation-specific representations) visual processing. Here we test these possibilities, using EEG to measure the effects of fixation between groups on early visual (domain-general) and face-specific components. Methods: Results from a speeded face identification task were used to classify subjects into two groups: ULs (fixation <1째 below eyes) and LLs (fixation <1째 above nose tip). EEG was recorded while subjects viewed rapidly intermixed images of houses and faces, with fixation enforced at either the eyes (Upper Fixation; UF) or the nose tip (Lower Fixation; LF) in alternating blocks. Results: LLs and ULs showed substantial differences in early visual components, with the P1 drastically reduced for LLs for faces but not houses, and a main effect of lowered P1 amplitude for UF trials. The later face-specific N170 component showed an interaction between looking group and fixation, such that ULs actually maximized response in LF trials while LLs showed similar responses across fixation. Conclusion: The results suggest that both basic domain-general and face-specific mechanisms may play a role in the interaction between fixation and face recognition ability.
Meeting abstract presented at VSS 2014