Contextual Influence On Facial Processing

July 23, 2021

It is widely investigated how context (e.g., information surrounding an experience or situation; Chen et al., 2020) influences (emotional) perception of our environment. Perception studies are aimed at discovering what processes underlie subjective experiences and how for instance (social) behavior is influenced as a result. A prominent way of exploring unconscious perception is through faces, facial processing being a sustained field of research which has provided established and reliable localized face-selective neural mechanisms (Haxby, Hoffman, & Gobbini, 2000). With the ability to display a great deal of character and identity as well as emotion, faces propose a relevant factor in the social world and theories of unconscious face processing are popular (Axelrod, Bar, & Rees, 2015; Lehmann et al., 2004; Stewart et al., 2012). Regardless of its expression, a face is a salient emotional stimulus allowing us to distinguish friend from foe and conveying crucial information for social interactions (e.g., identity, race, sex, attractiveness, direction of eye gaze). Thus, all faces, even so called “unexpressive” or “neutral” faces will have emotional significance and may have special access to visual attention (Palermo & Rhodes, 2007). Rapid facial processing serves as a good medium for investigating unconscious perception, since processes that occur in sensory cortices early on after stimulus onset that aim to process features of visual presentation are the basis of what we call perception

Based on the assumption that invisible faces can be partially processed early on in high-level visual networks, we used visible primes as contextual factors and indirectly measured unconscious processing with backward masked face localization tasks. Experiment 1 (n=23) used valanced sentence priming and expressional targets (e.g., happy and angry faces) to test whether emotional congruency effects (in reaction time and accuracy) could be observed but lacked statistical power and failed to provide significant results. Experiment 2 (n=58) was based on racial bias (namely, Black people associated with guns) and used images of tools and weapons as priming combined with neutral Black and White face-targets, with congruent conditions now described by Black-gun or White-tool trials. Again, no congruency effects were found, whereas we did find longer presentation positively influenced speed and accuracy. Thus, our findings lean towards the notion that these forms of contextual factors do not influence early perceptional processes or suggest insufficiency of our experimental design, demanding optimization. Despite not obtaining robust evidence for unconscious perceptional processing in the current experiments, the masking-priming paradigm as well as established early facial processing has previously shown to be opportunistic for the unconsciousness-field of study and is worth reconsidering as sufficient research remains limited to date.