title: The Two-Body Inversion Effect.
abstract: How does one perceive groups of people? It is known that functionally interacting objects (e.g., a glass and a pitcher tilted as if pouring water into it) are perceptually grouped. Here, we showed that processing of multiple human bodies is also influenced by their relative positioning. In a series of categorization experiments, bodies facing each other (seemingly interacting) were recognized more accurately than bodies facing away from each other (noninteracting). Moreover, recognition of facing body dyads (but not nonfacing body dyads) was strongly impaired when those stimuli were inverted, similar to what has been found for individual bodies. This inversion effect demonstrates sensitivity of the visual system to facing body dyads in their common upright configuration and might imply recruitment of configural processing (i.e., processing of the overall body configuration without prior part-by-part analysis). These findings suggest that facing dyads are represented as one structured unit, which may be the intermediate level of representation between multiple-object (body) perception and representation of social actions.
authors.affiliation: 1 Center for Brain and Cognition, Universitat Pompeu Fabra.|2 Institut des Sciences Cognitives-Marc Jeannerod, Unité Mixte de Recherche (UMR) 5304, Centre National de la Recherche Scientifique (CNRS), Université de Lyon.
authors.forename: Liuba
authors.initials: L
authors.lastname: Papeo
authors.affiliation: 3 Center for Mind/Brain Sciences (CIMeC), University of Trento.
authors.forename: Timo
authors.initials: T
authors.lastname: Stein
authors.affiliation: 1 Center for Brain and Cognition, Universitat Pompeu Fabra.|4 Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
authors.forename: Salvador
authors.initials: S
authors.lastname: Soto-Faraco
mesh_terms: D000293:Adolescent; D000328:Adult; D018594:Human Body; D006801:Humans; D010364:Pattern Recognition, Visual / Q000502:physiology*; D012938:Social Perception; D055815:Young Adult
keywords: configural processing; face perception; object recognition; scene perception; social perception