TIMING EFFECTS OF POSTEVENT INFORMATION ON INFANT MEMORY

The role of the timing of postevent information on retention was asses sed with 124 6-month-olds. In four experiments, infants learned to kic k to move a particular crib mobile (the original target), were passive ly exposed to a discriminably different mobile (the postevent informat ion), and were tested for recognition of the original mobile, the post event-exposure mobile, or a completely novel mobile 24 h later. All in terpolated exposures occurred after delays when infants' retention of the training mobile is excellent. In Experiment 1, the interpolated in formation precluded recognition of the training mobile (memory impairm ent) after all exposure delays. In Experiment 2, when the interpolated information was exposed within a week of training, infants treated th e exposure mobile as if they had actually been trained with it (memory facilitation). Despite the recognition failures in Experiments 1-2, b oth original and exposure mobiles later reactivated the training memor y, but only if the interpolated exposure was early in the retention in terval; if it was later, only the exposure mobile was an effective rem inder (Experiments 3A-3B). In Experiment 4, exposing postevent informa tion after longer delays led infants to respond to a completely novel mobile (categorization). These findings demonstrate that postevent inf ormation has different qualitative effects depending on its timing and provides a basis for understanding discrepant reports of postevent-in formation effects with children and adults. (C) 1996 Academic Press, I nc.