Object permanence after a 24-hr delay and leaving the locale of disappearance: the role of memory, space, and identity

Abstract

Fourteen-month-old infants saw an object hidden inside a container and were removed from the disappearance locale for 24 hr. Upon their return, they searched correctly for the hidden object, demonstrating object permanence and long-term memory. Control infants who saw no disappearance did not search. In Experiment 2, infants returned to see the container either in the same or a different room. Performance by room-change infants dropped to baseline levels, suggesting that infant search for hidden objects is guided by numerical identity. Infants seek the individual object that disappeared, which exists in its original location, not in a different room. A new behavior, identity-verifying search, was discovered and quantified. Implications are drawn for memory, spatial understanding, object permanence, and object identity.

Figure 1

The test room used for the memory test. The test object was hidden in the cupboard or the box as the infant watched from across the room. The cupboard was fixed on the floor, and the box was permanently attached to its top surface. The shading on the table, the box, and the cupboard denotes their appearance as a massive and spatially contiguous whole. E = the experimenter’s position when presenting the object hidings. S = the infants’ position as they observed the hidings and at the start of the memory test on Day 2. X and Y are locations on the floor where certain events were presented in the course of the procedure (see text for details). Several salient features of the test room were altered for infants assigned to the room-change conditions (see text for details). The figure is drawn to scale; see text for physical dimensions.