does not mean that study generally should be in short periods
with intervals of rest; it says nothing one way or the other on that
question. The probability is, since most students take a certain time
to get well "warmed up" to study, that fairly long periods of
consecutive study would yield larger returns than the same amount of
time divided into many short periods. What we have been saying here is
simply that repetition of the _same material_ fixes it better in
memory, when an interval (not necessarily an empty interval) elapses
between the repetitions.

Whole versus part learning.

In memorizing a long lesson, is it more economical to divide it into
parts, and study each part by itself till mastered, or to keep the
lesson entire and always go through the whole thing? Most of us would
probably guess that study part by part would be better, but
experimental results have usually been in favor of study of the whole.

If you had to memorize 240 lines of a poem, you would certainly be
inclined to learn a part at a time; but notice the following
experiment. A young man took two passages of this length, both from
the same poem, and studied one by the whole method, the other by the
part method, in sittings of about thirty-five minutes each day. His
results appear in the table.

LEARNING PASSAGES OF 240 LINES, BY WHOLE AND PART METHODS
(Pyle and Snyder)

Method of study Number of days Total number of
required minutes required

30 lines memorized per day,
then whole reviewed till it
could be recited 12 431

3 readings of whole per day
till it could be recited 10 348

{344}

Here there was an economy of eighty-three minutes, or nearly twenty
per cent., by using the whole method as against the part method.
Similar experiments have regularly given the same general result.

However, the matter is not quite so simple, as, under certain
conditions, the results tend the other way. Let us consider a very
different type of learning test. A "pencil maze", consisting of
passages or grooves to be traced out with a pencil, while the whole
thing was concealed from the subject by a screen, was so arranged that
it could be divided into four parts and each part learned separately.
Four squads of learners were used. Squads A and B learned the maze as
a whole, squads C and D part by part. Squads A