Dissociating attentional effects on the N170 event-related potential of faces and body parts

Attention was manipulated sensu Lavie's perceptual load theory to short time presentations (200 ms) of task-irrelevant unfamiliar unaltered faces, hands, and houses. Participants performed a letter detection task (X vs. N) under high (6 different letters) or low (6 identical letters) attentional load conditions. Letter strings were superimposed on task-irrelevant stimuli. Replicating and extending previous findings, while the typical pattern of face selectivity (faces > hands > houses) was observed under low load, N170 to faces, houses, and hands converged under high load. High load reduced N170 to faces, increased N170 to houses, and did not affect N170 to hands. These findings demonstrate that the category selectivity of N170 strongly depends on selective attention for faces and objects, while body parts and human bodies insensitive to selective attention.