Time windows in retention over the first year-and-a-half of life: spacing effects

The time window construct describes when and how an earlier experience will be enduring. According to the construct, there is a limited period after an event occurs, or time window, in which a second event can retrieve and be integrated with the memory of the first event. The construct also holds that when the integration occurs later in the time window, its effects are more enduring. This study examined the time window construct for session spacing with 6- to 18-month-old human infants. Infants of all ages exhibited the retention benefit of two (integrated) sessions only when the second session occurred within the time window, but only 6-month-olds remembered longer when it occurred late in the time window. Combined with 3-month-olds' data, these findings document the generality and predictive validity of the time window construct throughout the infancy period with one modification: Integration late in the time window only benefits infants younger than 9 months.