title: Brain potentials and integration of external and internal features into face representations.
abstract: In this ERP study we analyzed how different orders of presentation of external and internal features influence the integration of facial components into face gestalts. Participants carried out a face-feature matching task in which, in each trial, external (E) and internal (I) facial features were presented separately and in sequence, followed by a complete unfamiliar face (matching or mismatching). For the E-I group of participants the order of presentation was external features, internal features and then the complete face. The I-E group viewed the internal features first. Mismatch effects in complete faces were more conspicuous and lasted from about 300 to 600 ms with the order E-I, while those with the order I-E were scarcely observable, and significant only from 450 to 470 ms. The external features tended to elicit a larger P150, while the N170 was preferentially associated with the internal ones. A P360, probably indicating stimulus relevance, was present in both groups for external features, while it was associated with internal features only in the I-E group. These results suggest that in the E-I order the binding of facial features into a single face representation occurs according to a stepwise process which facilitates the integration. In turn, in the I-E order the processing related to the two sets of features appears more dissociated and is of a more componential nature. Moreover, we propose that the external features may be especially relevant for object categorization, while internal features would be more closely related to subsequent configural mechanisms.
authors.affiliation: Biological Psychology and Health Department, Psychology Faculty, Autónoma University of Madrid, Spain. ela.olivares@uam.es
authors.forename: Ela I
authors.initials: EI
authors.lastname: Olivares
authors.forename: Jaime
authors.initials: J
authors.lastname: Iglesias
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology*; D005071:Evoked Potentials / Q000502:physiology*; D005145:Face; D005260:Female; D005364:Field Dependence-Independence; D006801:Humans; D008297:Male; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D021641:Recognition, Psychology / Q000502:physiology*; D012016:Reference Values