Abstract
Background: Age, gender and ethnicity are all properties that can be deduced from a face, and all are also relevant to the processing of the identity of the face. Whether these use shared neural resources is not certain. Objective: We aimed to determine if the processing of one of these three dimensions influenced the processing of the others, on electrophysiological recordings. Methods: 13 observers with >3 years of experience with Asian and Caucasian faces made binary discriminative decisions of facial gender (male/female), age (young/old) or ethnicity (Asian/Caucasian) in separate blocks. Each block contained baseline trials in which only the relevant dimension varied and 'interference' trials in which both the relevant and one irrelevant dimension varied. Baselines vs. interference conditions were compared for each block separately in an analysis of N170 peak amplitude for right and left hemisphere electrodes. Results: Behavioral performance was equivalent for the three dimensions. The N170 was the most robust component being highest at P8 and PO8 electrodes. In Age discrimination blocks, trials with interference from ethnicity showed larger N170 amplitudes in the right hemisphere. There was no difference between the baseline and trials with interference from gender. In Ethnicity discrimination block, there was an opposite effect from interference from age, with smaller N170 amplitudes instead, and now only in the left hemisphere. Again, there was no difference in trials with interference from gender. In Gender discrimination blocks, trials with interference from age or ethnicity did not differ from the baseline trials. Conclusions: Age and ethnicity are processed in an interactive fashion, but gender perception appears to be independent, neither influencing processes while the other dimensions are being discriminated, nor being influenced by these other dimensions when subjects are discriminating gender.
Meeting abstract presented at VSS 2014