Matching of familiar faces and abstract patterns: behavioral and high-resolution ERP study

Electrical scalp-recorded components peaking approximately 350-400 ms were reported to be sensitive to both repetition/priming effects and face familiarity. We studied the categorical matching of familiar faces and compared it to the matching of abstract patterns. Nineteen healthy volunteers participated in the study. Each trial began with one of the two cues (S1) followed by consecutive pictures (S2 and S3). Each picture was a photograph of a familiar face with a superimposed abstract dot pattern. One cue directed attention to compare faces and another to compare patterns. Participants were asked to respond by pressing different buttons. A 128-channel EEG was recorded. Analysis was done for the 600-ms window from the S3 onset, for correct performance. The face comparison was better and faster than the pattern comparison. In the Face task, match/mismatch differences were local in 200-250 ms and large and widespread in 270-550 ms. In the Pattern task, differences were found in 30-270 ms, while on longer latencies they were lesser than those in the Face task. Priming was observed in the Face task as shorter reaction times and reduced N400-like components (both in prefrontal and parietal regions) for the same items as compared to the different ones. In the Pattern task, the results were more controversial.