Conscious Cogn 2014 Jul 18;27:233-45. Epub 2014 Jun 18.
UCL Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, UK; Wellcome Trust Centre for Neuroimaging, University College London, London WC1N 3AR, UK.
Investigating the limits of unconscious processing is essential to understand the function of consciousness. Here, we explored whether holistic face processing, a mechanism believed to be important for face processing in general, can be accomplished unconsciously. Using a novel "eyes-face" stimulus we tested whether discrimination of pairs of eyes was influenced by the surrounding face context. While the eyes were fully visible, the faces that provided context could be rendered invisible through continuous flash suppression. Two experiments with three different sets of face stimuli and a subliminal learning procedure converged to show that invisible faces did not influence perception of visible eyes. In contrast, surrounding faces, when they were clearly visible, strongly influenced perception of the eyes. Thus, we conclude that conscious awareness might be a prerequisite for holistic face processing.