THE TIME-WINDOW HYPOTHESIS - IMPLICATIONS FOR CATEGORIZATION AND MEMORY MODIFICATION

In four experiments, 100 three-month-old infants acquired a functional alphanumeric category in which they learned to kick to move a yellow block mobile on which the category cues were displayed. Following trai ning, infants were passively and briefly (3 min) exposed to functional information that a novel and highly physically dissimilar object (but terfly) shared with the training exemplars. If the exposure occurred a t any point within a 4-day time window of training, the novel object w as integrated with the prior memory of category training. It could cue retrieval of the training memory both on a transfer test 24 hours lat er and in a reactivation paradigm 3 weeks later. Moreover, when the ob ject was exposed at the end of the time window, its retention was sign ificantly prolonged, but at the expense of the original category membe rs. We propose that each succeeding retrieval progressively broadens t he time window within which new (or old) information can retrieve the memory or category concept. By this mechanism, new information can be integrated with old over relatively long intervals.