Evidence of Location Memory in 8-Month-Old Infants in a Nonsearch AB Task

Recent studies have shown that when an object is hidden in a location A and then in a location B, 8-month-old infants tend to search in A if forced to wait 3 s before retrieving the object, and to search randomly in A or B if forced to wait 6 s before retrieving the object (e.g., Diamond, 1985). A non-search method was devised to examine 8-month-olds' ability to remember the location of a hidden object. The infants saw an object standing on one of two placemats located on either side of the midline. Next, screens were pushed in front of the placemats, hiding the object from view. After 15 s, a hand reached behind one of the screens and reappeared holding the object. The infants looked reliably longer when the hand retrieved the object from behind the "wrong" as opposed to the "right" screen (where the object was actually hidden). This result suggests that the infants (a) remembered the object's location during the 15-s delay and (b) were surprised to see the object retrieved from behind the right (left) screen when they had last seen it on the left (right) placemat. These results indicate that 8-month-old infants' ability to remember the location of a hidden object is far better than their performance in the AB search task suggests. As such, the present results cast serious doubts on accounts that attribute infants' perseverative and/or random search errors to limited memory mechanisms.