A type of memory that is revealed when learning facilitates performance on a task that does not require conscious or intentional recollection of what was learnt. In a typical test, learners are shown a list of words or pictures, and then they are given an ostensibly unrelated task of recognizing fragmented forms of words or pictures in brief displays, and evidence for implicit memory is found in their ability to recognize the fragmented forms better if they have previously studied them. Evidence suggests that densely amnesic patients, who perform badly on standard memory tests, often perform normally on tests of implicit memory. The term was introduced by the Canadian psychologist Peter Graf (born 1951) and the US psychologist Daniel L. Schacter (born 1952) in an article in the Journal of Experimental Psychology: Learning, Memory, and Cognition in 1985. Compare explicit memory.