title: Ensemble perception of size in 4-5-year-old children.
abstract: Groups of objects are nearly everywhere we look. Adults can perceive and understand the 'gist' of multiple objects at once, engaging ensemble-coding mechanisms that summarize a group's overall appearance. Are these group-perception mechanisms in place early in childhood? Here, we provide the first evidence that 4-5-year-old children use ensemble coding to perceive the average size of a group of objects. Children viewed a pair of trees, with each containing a group of differently sized oranges. We found that, in order to determine which tree had the larger oranges overall, children integrated the sizes of multiple oranges into ensemble representations. This pooling occurred rapidly, and it occurred despite conflicting information from numerosity, continuous extent, density, and contrast. An ideal observer analysis showed that although children's integration mechanisms are sensitive, they are not yet as efficient as adults'. Overall, our results provide a new insight into the way children see and understand the environment, and they illustrate the fundamental nature of ensemble coding in visual perception.
authors.affiliation: Department of Psychology, University of Denver, USA.
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Sweeny
authors.affiliation: Department of Psychology, University of California - Berkeley, USA.
authors.forename: Nicole
authors.initials: N
authors.lastname: Wurnitsch
authors.affiliation: Department of Psychology, University of California - Berkeley, USA.
authors.forename: Alison
authors.initials: A
authors.lastname: Gopnik
authors.affiliation: Department of Psychology, University of California - Berkeley, USA.|Vision Science Group, University of California - Berkeley, USA.
authors.forename: David
authors.initials: D
authors.lastname: Whitney
mesh_terms: D001288:Attention / Q000502:physiology; D002657:Child Development; D002675:Child, Preschool; D004192:Discrimination, Psychological; D005260:Female; D005556:Form Perception / Q000502:physiology*; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology; D012680:Sensitivity and Specificity; D012858:Size Perception / Q000502:physiology*; D013997:Time Factors; D014785:Vision, Ocular