and C learned by spaced
trials, two trials per day. Squad B learned the whole thing at one
sitting; while squad D, which came off best of all, learned one part a
day for four days, and on the fifth day learned to put the parts
together. The results appear in the adjoining table, which shows the
average time required to master the maze by each of the four methods.

PART AND WHOLE LEARNING, SPACED AND UNSPACED,
IN THE PENCIL MAZE (From Pechstein)

Spaced trials Unspaced trials

Whole learning A 641 seconds B 1250 seconds

Part learning C 1220 seconds D 538 seconds

When the trials were spaced, the whole method was much the better; but
when the trials were bunched, the part method was much the better;
and, on the whole, the unspaced part learning was the best of all.
Thus the result stands in apparent contradiction with two accepted
laws: that of the advantage of spaced learning, and that of the
advantage of whole learning.

This contradiction warns us not to accept the "laws" {345} too
blindly, but rather to analyze out the factors of advantage in each
method, and govern ourselves accordingly. Among the factors involved
are the following four:

(1) The factor of interest, confidence and visible accomplishment--the
emotional factor, we might call it. This is on the side of part
learning, especially with beginners, who soon feel out of their depth
when wading into a long lesson, and lose hope of ever learning it in
this way. This factor is also largely on the side of unspaced as
against spaced learning, when the part studied is of moderate length
and when there are recitations to keep up the interest; for when the
learner sees he is getting ahead, he would rather keep right on than
wait for another day to finish. To have a task that you can hope to
accomplish at once, and to attack it with the intention of mastering
it at once, is very stimulating.

(2) The factor of recency, of "striking while the iron is hot". When
an act has just been successfully performed it can easily be repeated,
and when a fact has just been observed it can readily be put to use.
This factor is clearly on the side of unspaced learning; and it is
also on the side of part learning, since by the time you have gone
through the whole long lesson and got back to where you are now, the
recency value of what you have just now accomplished will have
evaporated.

(3) The factor of