What does the "jump up" around 24 hours in Murre and Dros's data suggest?

Retention dipped and then partly recovered around the one-day mark, consistent with sleep consolidating memories overnight.

When Murre and Dros (2015) replicated Ebbinghaus, their curve wasn't perfectly smooth — retention was a little higher around 24 hours than the pure-decay trend predicted. The leading interpretation is memory consolidation during sleep: overnight, the brain appears to stabilize and integrate recently learned material, offsetting some of the daytime decay. The study tip is practical: sleeping between a study session and a test is not lost time — it's part of the learning.