al management of memorizing: Is it
better to keep steadily going through the lesson till you have it, or
to go through it at intervals? If you were allowed a certain time, and
no more, in which to prepare for examination on a certain memory
lesson, how could the study time be best distributed? This question
also has received a very definite answer.

{342}

Spaced repetitions are more effective than unspaced. In an experiment
of Pieron, a practised subject went through a list of twenty numbers
with an interval of only thirty seconds between readings, and needed
eleven readings to master the list. But a similar list, with
five-minute intervals, was mastered in six readings; and the number of
readings went down to five with an interval of ten minutes, and
remained the same for longer intervals up to two days. With this
particular sort of lesson, then, ten minutes was a long enough
interval, and two days not too long, to give the greatest economy of
time spent in actual study.

In a somewhat different experiment in another laboratory, lists of
nonsense syllables were studied either two, four, or eight times in
immediate succession, and this was repeated each day till a total of
twenty-four readings had been given to each list; then, one day after
the last reading of each list, the subjects were tested as to their
memory of it. The result appears in the adjoining table.

EFFECT OF SPACED STUDY ON ECONOMY OF MEMORIZING (From Jost)

Distribution of
the 24 readings Total score Total score
of Mr. B. of Mr. M.
8 readings a day for 3 days 18 7

6 readings a day for 4 days 39 31

2 readings a day for 12 days 58 55

The widest distribution gave the best score. Undoubtedly, then, if you
had to memorize a poem or speech, you would get better value for time
spent if you read it once or twice at a time, with intervals of
perhaps a day, than if you attempted to learn it at one continuous
sitting. What exact spacing would give the very greatest economy would
depend on the length and character of the lesson.

Spaced study also fixes the matter more durably. Every student knows
that continuous "cramming" just before an {343} examination, while it
may accomplish its immediate purpose, accomplishes little for
permanent knowledge.

When we say that spaced repetitions give best results in memorizing,
that