Evaluated in three experiments a dynamic systems theory account of perseverative errors on "A-not-B" task. Found that 9-month-olds perseverated when reaching for identical targets, but made nonperseverative responses when reaching in the presence of a highly distinctive B target. Reach direction was jointly determined by target's…

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.…