The importance of awareness in face processing: A critical review of interocular suppression studies

Abstract

Human faces convey essential information for understanding others’ mental states and intentions. The importance of faces in social interaction has prompted suggestions that some relevant facial features such as configural information, emotional expression, and gaze direction may be processed unconsciously, yielding preferential access to awareness. This evidence has predominantly come from interocular suppression studies, with the most common method being the Breaking Continuous Flash Suppression procedure, which measures the time it takes different stimuli to overcome interocular suppression. Stimuli that overcome suppression faster arguably gain access to awareness faster. However, the procedures employed in such studies suffer from multiple methodological limitations. For example, they are unable to disentangle detection from identification processes, their results may be confounded by participants’ response bias and decision criteria, they typically use small stimulus sets, and some of their results attributed to detecting high-level facial features (e.g., emotional expression, gaze direction) may be confounded by differences in low-level visual features (e.g., contrast, spatial frequency). In this article, we review the evidence on whether relevant facial features promote access to awareness, we discuss the main limitations of the most popular methods used in the field, and we propose strategies to address these issues.

Minimal exposures reveal visual processing priorities

“…Previous studies have suggested a processing advantage and faster access to awareness for upright over inverted faces [15][16][17][18][19][20] , and for emotional over neutral faces 21,22 . (Although the latter claim, in particular, has been challenged [23][24][25][26] ). If so, processing -and possibly awareness -of upright and emotional faces should require shorter minimal exposures than inverted and neutral faces, respectively.…”