He noted the time it took to do this. Later, perhaps the next day, he would study the list again until he could recall it without error. He noted that he usually could recall without error in less time on the second attempt than on the first. He graphed his findings and showed it was possible to quantify memory behavior. Implicit memory has to do with something like savings, but it does not involve the conscious recollection aspect of memory.
Implicit memory is measured as a facilitation or bias in performance resulting from past experience.
Implicit memory is like savings, then, in that subjects are faster at a task because of prior experience. It differs from savings in that it can be measured even if the person is not consciously recollecting or aware of the particular first experience that is causing the facilitation. Implicit memory also differs in that it is not limited to a savings in time. They studied amnesics. These amnesics suffered from poor explicit memory for new events.