A rich tradition in developmental psychology explores physical reasoning in infancy. However, no research to date has investigated whether infants can reason about physical objects that behave probabilistically, rather than deterministically. Physical events are often quite variable, in that similar-looking objects can be placed in similar…

Two experiments examined 6-month-olds' ability to discriminate between visual displays of various number of dots varying in size and position, and with controls for other extraneous variables. Findings indicated that infants could discriminate between large sets on the basis of numerosity if they differed by a large ratio (8 versus 16, but not 8…

Four experiments used a preferential looking method to investigate 6-month-old infants' capacity to represent numerosity in visual-spatial displays. Building on previous findings that such infants discriminate between arrays of eight versus 16 discs, but not eight versus 12 discs (Xu & Spelke, 2000), Experiments 1 and 2 investigated whether…

Examines evidence that the research community studying infants' object concept and the community concerned with adult object-based attention have been studying the same natural kind. Maintains that the discovery that the object representations of young infants are the same as the object files of mid-level visual cognition has implications for both…

Responds to Needham and Baillargeon's criticisms and offers an alternative resolution of the conflicting results between the laboratories regarding abilities of infants less than 12 months to use property/featural information for object individuation. Maintains that kind concepts are acquired as infants approach their first birthday and that…