The present studies investigated the memory retention of words and its relationship to sleep. The studies involved 4 college students and the first study followed a series of longitudinal within-subjects correlational assessments of hypotheses relating overnight memory retention to the following three other variables: hippocampal changes during sleep, quality of sleep, and quantity of sleep. After finding the highest correlation between quantity of sleep and memory retention, the causal relationship between these two variables was further experimentally tested. Sleep quantity was manipulated by randomly assigning each day across a two-week period to one of two possible conditions: a day with a 3-hour nap versus a day with no naps. The results of the experiment supported the hypothesis that increases in the amount of sleep result in a greater memory retention. These results are of importance for college students in maintaining a healthier academic profile and suggest that greater memory retention is capable by having adequate sleep.
