Decrement Through Lack of Exercise Forgetting

Now we must consider the converse relation--decrement through lack of exercise. There is some indication that these conditions are related physiologically; but until our information upon the matter is more precise, such topics as fatigue and forgetting may be discussed in the same chapter only as a matter of convenience.

The biological law of atrophy through disuse expresses the inclusiveness of the phenomena of forgetting at a descriptive rather than an explanatory level. We do know, however, that many of the phenomena of forgetting are partially due to some type of central inhibition. After a particular neural organization has been established in the central nervous system, it passes into a relatively quiescent state until it is rearoused. Whatever this resting state consists in, it is markedly influenced by active processes.

The factors controlling the rate of forgetting include (1) the amount of overlearning, (2) the spacing of learning periods, (3) the method employed in learning, and (4) individual differences. The degree of forgetting is definitely related to the degree of learning. Other things being equal, forgetting takes place less easily with overlearning, with properly spaced repetitions, with methods favoring clear impression, and with a nervous system which is easily educable. If the traces of two neural organizations are equivalent as measured by redintegrative performance, the older trace will decay the more slowly. The natural inference is that age brings a gradual breakdown in the elastic resistance of nervous tissue to impression, so that those stimuli which come later in life are less functional. The fact that the same conditions which make for efficiency in learning also favor slow forgetting suggests an intimate relation between the two phenomena. However there are notable exceptions; and more analytical studies of both need to be made. Improvement through use and decrement through disuse seem axiomatic until we recall the truth behind James' often-quoted remark that "we learn to swim in the winter and to skate in the summer." Apparent improvement through disuse suggests an affinity with fatigue-inhibition as well as with learning-facilitation.