The time course of visual competition to the presentation of centrally fixated faces

A recent event-related potential (ERP) study showed that the occipitotemporal component N170 recorded to a face stimulus appearing in the peripheral visual field is strongly reduced when subjects are concurrently fixating another face stimulus. This suggests that concurrently presented face stimuli compete for neural representation in the occipitotemporal cortex between 100 and 200 ms following stimulus onset. We tested whether this competition can be observed for a foveally presented face stimulus appearing next to either two peripheral face pictures or two peripheral control stimuli. The N170 in response to the fixated central face stimulus was substantially reduced (approximately 20% of signal) when it was presented next to peripheral face stimuli. The response suppression was smaller in magnitude than in a previous study where the competing stimulus was fixated and the target stimulus appeared in the periphery. Besides providing a better control for attentional and eye movement confounds, the concurrent stimulation paradigm for fixated face stimuli in ERPs offers a powerful tool to investigate the time course and the nature of the interactions between face and nonface object representations.