Abstract
Faces convey a wealth of information critical for the guidance of behavior in social contexts. Therefore, in the human brain a highly specialized network is dedicated to the rapid and efficient processing of facial information. A number of previous studies have shown that parts of this network can process salient facial features, such as emotional expressions, even without awareness. In contrast, it has remained largely unknown, whether face-responsive brain regions can also process the direction of another’s gaze â€" a highly relevant signal for social interactions â€" unconsciously. To this end, we conducted a functional magnetic resonance imaging study in which faces were presented whose gaze was either directed towards or away from the observer. Face stimuli were either presented visibly or rendered invisible through interocular suppression. Participants’ awareness of the faces was probed by a confidence rating and a two-alternative forced-choice (2AFC) task regarding the spatial location of the face on each trial. Only trials in which participants reported unawareness of the face stimuli in the confidence rating were taken into account. Despite subjective reports of unawareness, one half (N = 9) of the participants performed above chance in the 2AFC task, while the other half performed at chance level. For both these subgroups, we observed gaze-specific neural responses in the fusiform face area (FFA), superior temporal sulcus (STS), and amygdala, which have previously been shown to be involved in the processing of eye gaze of visible faces. In all three regions activations for averted gaze was higher compared to direct gaze. Our results demonstrate a sensitivity of the human brain to other people’s eye gaze direction, even when the observer is unaware of their faces. This underlines the high relevance of this facial information for human social interactions.
Meeting abstract presented at VSS 2014