Spontaneous remembering after recall failure.

Verbal free recall of lists of 20 items increased on repeated recall attempts, without any further presentation of each word after it had been recalled just once. Such restricted presentation resulted in long-term storage and retention of almost all 20 items, as shown by their eventual spontaneous retrieval without further presentation. Most items that failed to be recalled were retrieved again later without any further presentation, indicating that such failures represent retrieval failures rather than loss from storage and that free recall verbal learning requires retrieval from long-term storage.