A central feature of human psychology is our pervasive tendency to divide the social world into "us" and "them". We prefer to associate with those who are similar to us over those who are different, preferentially allocate resources to similar others, and hold more positive beliefs about similar others. Here we investigate the developmental…

A critical challenge for visual perception is to represent objects as the same persisting individuals over time and motion. Across several areas of cognitive science, researchers have identified cohesion as among the most important theoretical principles of object persistence: An object must maintain a single bounded contour over time. Drawing…

Four experiments examined 8-month-olds' ability to reason about collections of objects. Findings suggested that infants' expectations about object behavior do not automatically apply to any and all portions of matter within the visual field. The behavior of an entity and infants' prior experience played roles in determining whether infants will…