An ERP study of expectancy violation in face perception

Expectancies about face-structure can be induced by viewing parts of faces, which generates constraints due to two types of knowledge: feature-content and configuration. In a first experiment ERPs were recorded when parts of familiar faces were completed with incongruent features (from another face), as opposed to congruent features (from the same face). All features were in the correct configuration. An enhanced negativity was found for incongruent completions (N374) that was larger over the right side of the scalp. This replicates the results of Valdes-Sosa and Bobes (1990). In another two experiments, ERPs were recorded when parts of familiar faces were completed by congruent features, but sometimes placed in an incorrect position. In one experiment the features were jumbled; in the other, the features were slightly displaced. These configuration distortions were associated to late positive components, with a maxima at the centro-parietal region, of equal amplitude for both kinds of configuration anomalies. The N374 component seems to be a non-linguistic analog of the N400. The different ERP signatures for expectancy violations of configuration and feature-content suggest that these types of information are processed separately at some stages.