Fixation-related electrical potentials during a free visual search task reveal the timing of visual awareness

• Published in: iScience 2023-07, Vol.26 (7), p.107148-107148, Article 107148
• Main Authors: Qiu, Zeguo, Becker, Stefanie I., Xia, Hongfeng, Hamblin-Frohman, Zachary, Pegna, Alan J.
• Format: Article
• Language: English
• Subjects: Cognitive neuroscience; Optical signal processing; Optics
• ISSN: 2589-0042; 2589-0042
• DOI: 10.1016/j.isci.2023.107148

It has been repeatedly claimed that emotional faces readily capture attention, and that they may be processed without awareness. Yet some observations cast doubt on these assertions. Part of the problem may lie in the experimental paradigms employed. Here, we used a free viewing visual search task during electroencephalographic recordings, where participants searched for either fearful or neutral facial expressions among distractor expressions. Fixation-related potentials were computed for fearful and neutral targets and the response compared for stimuli consciously reported or not. We showed that awareness was associated with an electrophysiological negativity starting at around 110 ms, while emotional expressions were distinguished on the N170 and early posterior negativity only when stimuli were consciously reported. These results suggest that during unconstrained visual search, the earliest electrical correlate of awareness may emerge as early as 110 ms, and fixating at an emotional face without reporting it may not produce any unconscious processing. [Display omitted] •Electrophysiological correlates of awareness emerge at 110 ms in free visual search•Conscious processing of fearful faces emerges later in the N170 time range•We did not find evidence for unconscious processing of fearful expressions Subject areas: Cognitive neuroscience; Optical signal processing; Optics.