=6. Use of Knowledge as Motive.=--In the preceding cases, interest in
the problem is made to rest primarily upon some native instinct, or
tendency. It is to be noted, however, that as the child advances in the
acquisition of knowledge, or experience, there develops in him also a
desire for mental activity. In other words, the normal child takes a
delight in the use of any knowledge over which he possesses adequate
control. It is to be noted further, that the child masters the new
problem by bringing to bear upon it suitable ideas selected out of his
previously acquired experiences. It is evident, therefore, that, when a
lesson problem is presented to the child in such a way that he sees a
connection between it and his present knowledge and feels, further, that
the problem may be mastered by a use of knowledge over which he has
complete mastery, he will take a deeper interest in the learning
process. When, on the other hand, he has imperfect control over the old
knowledge from which the interpreting ideas are selected, his interest
in the problem itself will be greatly reduced. Owing to this fact, the
teacher may adapt his lesson problems, or motives, to the stage of
development of the pupils. In the case of young children, since they
have little knowledge, but possess a number of instinctive tendencies,
the lesson problem should be such as may be associated with their
instinctive tendencies. Since, however, the expressing of these
tendencies necessarily brings to the child ideas, or increases his
knowledge, the pupil will in time desire to use his growing knowledge
for its own sake. Here the child becomes able to grasp a problem
consciously, or in idea, and, so far as it appeals to his past
experience, will desire to work for its solution. Thus any problem which
is recognized as having a vital connection with his own experience
constitutes for the child a strong motive. For older pupils, therefore,
the lesson problem which constitutes the strongest motive is the one
that is consciously recognized and felt to have some direct connection