Unconscious fearful body perception enhances discrimination of conscious anger expressions under continuous flash suppression

The continuous flash suppression (CFS) paradigm is increasingly used to study unconscious visual perception. Our goal was to use CFS and to to compare the results with previous findings from patients with brain lesions, and studies of healthy participants. We used an emotion discrimination task and bilaterally presented whole-body postures expressing fear or anger, rendering the stimuli invisible in either one of the visual fields. We found that the CFS presentation did not yield the classical redundant target effect of response facilitation when the unconsciously seen stimuli had congruent emotions; instead we found a facilitation effect in reaction times by body stimuli of incongruent emotions, especially by the unconscious fearful body facilitating discrimination of conscious angry body. Our results with healthy participants showed similarities to hemianopia patients without blindsight, but not to blindsight or neglect patients, indicating that unconscious visual processing is not a single phenomenon, but is likely to involve multiple mechanisms, processes and brain regions. Further studies are necessary to validate the facilitation effect of fearful bodies on other tasks, and to study the neural substrates of this effect.