are operative in securing the best type of
memory, still the efficiency of a given memory may be due more to the
unusual power of one of them than to the combined effect of the three.
It is this difference in the functioning of these three factors which is
primarily responsible for certain types of memory which will be
discussed later. It must also be borne in mind that the power of these
factors to operate in determining recall varies somewhat with age.
Little children and old people are more dependent upon mere
retentiveness than upon either of the others, the former because of lack
of experience and lack of habits of thought, the latter because of the
loss of both of these factors. The adult depends more on the
organization of his material, while in the years between the number of
the clews is probably the controlling factor. Here again there is no
sharp line of division; all three are needed. So in the primary grades
we begin to require children to organize, and as adults we do all we can
to make the power of retention operate at its maximum.

Many methods of memorizing have been used by both children and adults.
Recently experimental psychology has been testing some of them. So far
as the learner is concerned, he may use repetition, or concentration, or
recall as a primary method. Repetition means simply the going over and
over again the material to be learned--the element depended upon being
the number of times the connection is made. Concentration means going
over the material with attention. Not the number of connections is
important, but the intensity of those connections. In recall the
emphasis is laid upon reinstating the desired connections from within.
In using this method, for instance, the learner goes over the material
as many times as he sees necessary, then closes the book and recalls
from memory what he can of it.

The last of the three methods is by far the best, whether the memory
desired be rote or logical, for several reasons. In the first place it
involves both the other methods or goes beyond them. Second, it is
economical, for the learner knows when he knows the lesson. Third, it is
sure, for it establishes connections as they will be used--in other
words, the learning provides for recall, which is the thing desired,
whereas the other two methods establish only connections of impression.
Fourth, it tends to establish habits that are of themselves worth while,
such as assuming responsibility fo