title: Individual differences in ensemble perception reveal multiple, independent levels of ensemble representation.
abstract: Ensemble perception, including the ability to "see the average" from a group of items, operates in numerous feature domains (size, orientation, speed, facial expression, etc.). Although the ubiquity of ensemble representations is well established, the large-scale cognitive architecture of this process remains poorly defined. We address this using an individual differences approach. In a series of experiments, observers saw groups of objects and reported either a single item from the group or the average of the entire group. High-level ensemble representations (e.g., average facial expression) showed complete independence from low-level ensemble representations (e.g., average orientation). In contrast, low-level ensemble representations (e.g., orientation and color) were correlated with each other, but not with high-level ensemble representations (e.g., facial expression and person identity). These results suggest that there is not a single domain-general ensemble mechanism, and that the relationship among various ensemble representations depends on how proximal they are in representational space.
authors.affiliation: Department of Psychology, Harvard University.
authors.forename: Jason
authors.initials: J
authors.lastname: Haberman
authors.affiliation: Department of Psychology, Harvard University.
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Brady
authors.affiliation: Department of Psychology, Harvard University.
authors.forename: George A
authors.initials: GA
authors.lastname: Alvarez
mesh_terms: D000293:Adolescent; D000328:Adult; D053483:Eye Movement Measurements; D005149:Facial Expression; D000066499:Facial Recognition / Q000502:physiology; D006801:Humans; D007206:Individuality; D010364:Pattern Recognition, Visual / Q000502:physiology*; D055815:Young Adult