he features of the picture. After five
days he was retested in the same way, and again after fifteen days,
etc. In one respect this is not a typical memory experiment, since
the test after five days would revive the subject's memory of the
picture and slacken the progress of forgetting. The experiment
corresponds more closely to the conditions of ordinary life, when we
do recall a scene at intervals; or it corresponds to the conditions
surrounding the eye-witness of a crime, who must testify regarding
it, time after time, before police, lawyers and juries. However, the
subjects in this experiment realized at the time that they were to
be examined later, and studied the picture more carefully than the
eye-witness of a crime would study the event occurring before his
eyes; so that the per cent. of error was smaller here than can be
expected in the courtroom.

It must be understood that this classical curve of forgetting only
holds good, strictly, for material that has _barely_ been learned.
Reactions that have been drilled in thoroughly and repeatedly fall off
very slowly at first, and the further course of the curve of
forgetting has not been accurately followed in their case. A typist
who had spent perhaps two hundred hours in drill, and then dropped
typewriting for a year, recovered the lost ground in less than an hour
of fresh practice, so that the retention, as measured by the saving
method, was over ninety-nine per cent.

Somewhat different from the matter of the curve of forgetting is the
question of the _rate of forgetting_, as {353} dependent on various
conditions. The rate of forgetting depends, first, on the thoroughness
of the learning, as we have just seen. It depends on the kind of
material learned, being very much slower for meaningful than for
nonsense material, though both have been learned equally well. Barely
learned nonsense material is almost entirely gone by the end of four
months, but stanzas of poetry, just barely learned, have shown a
perceptible retention after twenty years.

Very fortunately, the principles of economy of memorizing hold good
also for retention. Forgetting is slower when relationships and
connections have been found in the material than when the learning has
been by rote. Forgetting is slower after active recitation than when
the more passive, receptive method of study has been employed.
Forgetting is slower after spaced than after unspaced study, a