Download Full Text (833 KB)


Research indicates that memories are strengthened by consolidation, the incorporation during sleep into a previously established memory network (Rasch & Born, 2008; 2013). Memories are initially unstable after encoding and sleep consolidation increases resistance to interference (Robertson, 2011). On the first day of a two-day experiment designed to examine whether an encoding task interruption and a delay in retrieval would affect later memory consolidation, participants memorized pictures of common objects (e.g., owl) presented in a slideshow. Participants were assigned to complete either an immediate recognition test that included studied and unstudied pictures (“lures”), or return the following day to complete a delayed recognition test. Some were assigned to be tested on the two consecutive days. There were three hypotheses: (a) target pictures tested for memory only on the second day would be remembered as good if not better, due to sleep consolidation, than when tested for memory only on the first day; (b) there would be serial position effects on sleep consolidation of the target pictures due to the task interruption, such that recency before interruption would be reduced while other serial position effects would be stable; (c) pictures tested on both days would be better remembered on the second day than on the first. A 3 (Test day: Day 1, Day 2 or both days) x 2 (Test stimulus: Targets and Lures) ANOVA compared correct discrimination for each condition. The interaction between stimuli and testing day was significant and strong (p = .001, η2 = .189), indicating that participants tested on Day 2 were as correct as those on Day 1 in identifying picture targets. However, although participants on Day 2 remembered more targets, they also incorrectly remembered more lures than on Day 1. Sleep consolidation has an overall effect of maintaining the strength of “real” memories over time.

Publication Date


Project Designation

Independent Research

Primary Advisor

Susan T Davis

Primary Advisor's Department



Stander Symposium poster


Presenters: Victoria Lynne Karpuszka, Sarah Phoebe Lawson, Madeline Margaret Nash, Alicia Michelle Selvey, Gabriella Louise Silone, Carolina Sofia Vazquez

Sleeping on