THE EFFECT OF OVERLEARNING UPON RETENTION
Among the important problems in the general field of learning and memory is the effect of overlearning upon retention. By "overlearning" is meant practicing an act to an extent greater than that necessary just to learn it. For example, if the act were memorizing a list of words, overlearning would mean going over the list more times than was necessary to repeat it just once correctly.
In general, everyone would agree that the more one practices anything, provided he works at it attentively and purposefully, the better he will be able to recall it later. Yet this, like many plausible notions in the field of psychology, must be experimentally demonstrated before it can be accepted as true. Furthermore, even if overlearning does usually result in improved retention, it is not certain just how great the benefits derived from different amounts of overlearning will be. Suppose it takes 10 repetitions to learn a list of words, which are to be recalled a week later. If the subject after learning the list had practiced it five times more, which would mean giving it 50 per cent more repetitions, would he remember 50 per cent more of it? Or, if he had given the list 10 additional repetitions, making 20 in all, would his recall be 100 per cent better? Likewise, the value of a given amount of overlearning might not be the same after different intervals had elapsed between the original learning and the retention test. If, for example, 50 per cent overlearning increased one's retention 60 per cent on a test given one day later, would its value be greater or less if the interval had been, say, four weeks instead of one day only?
For questions like these, common sense can give no clear answer. The last two problems, in particular, are of considerable practical significance, but they can be solved only by the carefully controlled experimentation which is exemplified in the studies reviewed in this chapter.