When you know that you know and when you think that you know but you don't.

College students rated the likelihood of recall of individual words presented for free recall learning. Predictions were made using a 7-point scale immediately following an item’s presentation in the list. To-be-rated items included those presented one time, as well as items presented twice in either a massed (MP) or distributed (DP) manner. Twice-presented items were rated as more likely to be recalled than items presented once, and they were; MP items were judged more likely to be recalled than DP items, but they were not. The finding that subjects think that they know MP items when they do not suggests why processing may be less for massed than for distributed presentations. As such, these results provide support for the attenuation of attention hypothesis of the spacing effect in free recall.