State-based metacognition: how time of day affects the accuracy of metamemory.

Although there is an abundance of research on how stimulus characteristics and encoding conditions affect metamemory, and how those effects either do or do not mirror effects on memory, there is little research on whether and how characteristics of participants' states-like mood, fatigue, or hunger-affect metamemory. The present study examined whether metamemory ability fluctuates with time of day. Specifically, we evaluated whether learners can successfully account for the effects of time of day on their memory, and whether metacognitive monitoring is more accurate at an individual's optimal time of day. Young adults studied and recalled lists of words in both the morning and the afternoon, providing various metamemory judgements during each test session. We replicated the finding that young participants recalled more words in the afternoon than in the morning. Prior to study, participants did not predict superior recall in the afternoon, but they did after they had an opportunity to study the list (but before the test on that material). We also found that item-by-item predictions were more accurate in the afternoon, suggesting that self-regulated learning might benefit from being scheduled during times of day that accord with individuals' peak arousal.