This study tested Piaget's explanation of infants' perseverative error in manual search by comparing searches when the object was (1) hidden, (2) covered but visible, and (3) uncovered. Errors occurred under all three conditions, with conflict at a maximum when the object was hidden. (Author/JMB)

Twenty-five infants were tested every two weeks on the AB Object Permanence Task, from the time they first reached for a hidden object until they were 12 months old. Results indicate that the AB provides an index of the ability to carry out an intention based on stored information despite a conflicting habitual tendency. (Author/RH)

Four experiments examined 8- to 12-month olds on search and nonsearch A not B tasks, a one-location task, and control tasks. Results indicated memory for where object was hidden and expectations of where it should be found. The effect occurred at delays at which infants made the A not B error when searching, and at a longer 15-second delay.…