it is misleading. The general law of the effect of disuse on a memory is
true, but under some circumstances its effect is mitigated by the
presence of other factors whose presence has been unnoted. Sometimes
this improvement without practice is explained by the fact that at the
last practice period the actual improvement was masked by fatigue or
boredom, so that disuse involving rest and the disappearance of fatigue
and boredom produces apparent gain, when in reality it but allows the
real improvement to become evident. Sometimes a particular practice
period was accompanied by certain undesirable elements such as worry,
excitement, misunderstandings, and so on, and therefore the improvement
hindered or masked, whereas at the next period under different
conditions there would be less interference and therefore added gain.
All experimental evidence is against the opinion that mere disuse in and
of itself produces gain. In fact, all results point to the fact that
disuse brings deterioration.

In the case of memory, as has already been described in habit formation,
reviews which are organized with the period between repetitions only
gradually lengthened may do much to insure permanence. It is entirely
feasible to have children at the end of any school year able to repeat
the poems or prose selections which they have memorized, provided that
they have been recalled with sufficient frequency during the course of
the year. In a subject like geography or history, or in the study of
mathematics or science, in which logical memory is demanded, systematic
reviews, rather than cramming for examinations, will result in
permanence of command of the facts or principles involved, especially
when these reviews have involved the right type of organization and as
many associations as is possible.

It is important in those subjects which involve a logical organization