Sleep improves memory for the content but not execution of intentions in adolescents

Sleep benefits prospective memory in young adults probably in part due to its well-established role in enhancing declarative memory, thereby facilitating retrieval of the intention content. In prior work on adolescents, we did not detect differences in prospective memory comparing five nights of sleep restriction and adequate sleep. Here, we examined whether this might be attributed to a limited role of sleep in benefiting the declarative content in this age group, and whether a sleep benefit on prospective memory would be uncovered with a shorter retention interval.

A total of 59 adolescents (mean ± standard deviation: 16.55 ± 0.94 years) were instructed to remember to press a special key in response to two target words embedded in a semantic categorization task. Memory was tested after a 12-h retention interval, which included either overnight sleep (21:00-09:00, n = 29) or daytime wakefulness (09:00-21:00, n = 30).

We found no significant group difference in the percentage of target words correctly responded to (mean ± standard error of the mean for the sleep group: 32.76 ± 6.69%; wake group: 41.67 ± 7.61%, t = 0.88, p = 0.38). However, participants who slept recalled more target words compared to those who stayed awake (98.28 ± 1.72% vs. 86.67 ± 5.32%, t = 2.05, p < 0.05). In addition, a significantly greater proportion of sleep participants (n = 28 of 29) compared to wake participants (n = 24 of 30) recalled both target words correctly (χ² = 3.76, p < 0.05).

These findings suggest that during adolescence, sleep plays a more prominent role in improving memory for the content as compared to the execution of intentions.