Abstract
The human face bears prominent biological and social meanings, making it detected quickly and automatically (as early as after 100ms of visual presentation). By contrast, it has been suggested that face identity processing depends on selective attention (Palermo & Rhodes, 2007). Our study used a fast periodic visual stimulation (FPVS) approach to examine the effect of selective attention on face identity discrimination at a glance. We recorded 128-channel EEG while participants viewed 70s sequences of female faces shown at 6 Hz. Within each sequence, a randomly selected identity was repeated (A) with different female face identities (B, C…) embedded every 7th image (AAAAAABAAAAAAC…). Responses at 6 Hz reflect common visual processing of all stimuli, while responses at 0.857 Hz (i.e., 6 Hz/7) reflect face identity discrimination (Liu-Shuang et al., 2014). Participants performed two tasks: (1) on Attend Fixation trials, participants monitored the central fixation cross for color changes (7 targets); (2) on Attend Face trials, participants responded to male faces which randomly replaced a female face identity change (7 targets). Although there were robust face discrimination responses in the orthogonal task as shown previously, attending to face gender increased responses on all electrodes, including the bilateral occipito-temporal regions. This effect does not appear to stem from a general increase in attention as behavioral performance and 6-Hz common visual responses did not differ between conditions. Thus, it appears that selective attention can modulate face identity discrimination in a rapid visual stream, but is not mandatory.
Meeting abstract presented at VSS 2017