Tested two competing hypotheses explaining infants' failure to search for an object in a new hiding place: (1) that the concept of object is not yet differentiated from the concept of place, and (2) that difficulties in spatial localization are responsible for the search failure. (Author/JMB)

A hypothesized developmental sequence of agent use in pretending was tested in 36 infants between 14 and 24 months of age and was compared with the development of object permanence. (JMB)

Presents a study of the development of self-recognition in infants from 6 to 24 months of age. The development of self-recognition is compared to the development of object permanence. (BD)

Presents a study of decalage between object permanence and person permanence. Decalage was influenced by environmental as well as stimulus factors with infants tested between 6- and 81/4-months/of-age. (BD)

This study explored the relationship between the mother-infant interaction and the concurrent perceptual-cognitive and intellectual status of the infant. One hundred and eight-nine 12-week-old infants were given a battery of perceptual-cognitive tasks, including the Mental Developmental Index (MDI) of the Bayley Scales, the Corman-Escalona Scales…

Attempts to determine whether infants' performance in two search tasks is related to their entry into Stage 6 of object permanence development (thereby testing Piaget's claim that only Stage 6 infants possess the capacity for representation). (BD)