reasonable length. The method of committing by wholes instead of parts not
only economizes time and effort in the learning, but also gives a better sense of
unity and meaning to the matter memorized.
Rate of Forgetting.—The rate of forgetting is found to be very much more rapid
immediately following the learning than after a longer time has elapsed. This is
to say that of what one is going to forget of matter committed to memory
approximately one-half will fall away within the first twenty-four hours and
three-fourths within the first three days. Since it is always economy to fix afresh
matter that is fading out before it has been wholly forgotten, it will manifestly
pay to review important memory material within the first day or two after it has
once been memorized.
Divided Practice.—If to commit a certain piece of material we must go over it,
say, ten different times, the results are found to be much better when the entire
number of repetitions are not had in immediate succession, but with reasonable
intervals between. This is due, no doubt, to the well-known fact that associations
tend to take form and grow more secure even after we have ceased to think
specifically of the matter in hand. The intervals allow time for the associations to
form their connections. It is in this sense that James says we "learn to swim
during the winter and to skate during the summer."
Forcing the Memory to Act.—In committing matter by reading it, the memory
should be forced into activity just as fast as it is able to carry part of the material.
If, after reading a poem over once, parts of it can be repeated without reference
to the text, the memory should be compelled to reproduce these parts. So with all
other material. Re-reading should be applied only at such points as the memory
has not yet grasped.
Not a Memory, But Memories.—Professor James has emphasized the fact,
which has often been demonstrated by experimental tests, that we do not possess
a memory, but a collection of memories. Our memory may be very good in one
line and poor in another. Nor can we "train our memory" in the sense of
practicing it in one line and having the improvement extend equally to other
lines. Committing poetry may have little or no effect in strengthening the
memory for historical or scientific data. In general, the memory must be trained
in the specific lines in which it is to excel. General training will not serve except
as it may lead to better modes of learning what is to be memorized.