Electrophysiological study of contextual variations in a short-term face recognition task.

International audienceEvent-related potentials (ERPs) were recorded during two short-term recognition tasks using unfamiliar faces. These experiments are based on the process dissociation procedure (PDP), whereby the exclusion criterion was an intrinsic context or extrinsic context, the facial expression (Experiment 1) or background (Experiment 2), respectively. The results indicate that retrieval orientation, in addition to extensive strategic control, affects both the frontal (N250) and temporoparietal (P3b) components. Furthermore, these data indicate that an early frontal modulation interacts between processing that bears on the face (interactive intrinsic context) and processing that bears on two objects at the same time (interactive extrinsic context), in which, in the latter case, that the background change led to an early modulation at the frontal sites in the left hemisphere. These results are consistent with the idea that frontal effects reflect differences in the nature of the information during retrieval and postretrieval processes involved. Furthermore, that the left posterior repetition effect appears to be a manifestation of the retrieval of relevant contextual information that perturbs the recognition decision, whereas the right posterior repetition effect reflects to be the outcome of the retrieval of the face as a whole. Finally, results are in concordance with the hypothesis that the difference during recognition with or without source memory may be in the strength of the relationship between the target and the contextual information to be retrieved. In essence, that automatic and controlled processes in a given context depends on both task-related and target-related constraints