When even arbitrary order becomes important: developments in reliable temporal sequencing of arbitrarily ordered events.

By late in the first year of life, children show temporally ordered recall of event sequences, the orders of which are constrained by enabling relations; they do not reliably recall arbitrarily ordered events. Using elicited imitation, in two experiments, we examined age- and experience-related changes in young children's recall of events, the orders of which are arbitrary. The changes were found to have implications for the efficacy of verbal reminding and to be related to developments in language. Specifically, on the basis of a single experience, 16-month-olds did not accurately recall arbitrarily ordered event sequences either immediately or after a two-week delay (Experiment 1); 22-month-olds recalled the events immediately, but not after the delay; by 28 months, children recalled the events even after the delay (Experiment 2A). This development was accompanied by changes in the ability to benefit from verbal reminders: 28-month-olds' recall was facilitated by provision of verbal reminders, whereas that of the younger children was not. Moreover, age-related changes in accurate reproduction of lengthy arbitrarily ordered event sequences were found to be related to developments in language (Experiment 2B). Critically, the limitations on 1-year-olds' performance that are overcome with age are not absolute: After three experiences, 16-month-olds accurately recalled the events after a two-week delay; their recall was facilitated by verbal reminders (Experiment 1). The implications of these findings are discussed.