INTEREST AND EFFORT
individual, complicated activities of a long duration—that is, with results that are long postponed. And, as we have already seen, it is this prolongation and postponement which requires an increasing use of intelligence. The use of tools and appliances (in the broad sense) also demands a greater degree of technical skill than does mastery of the use of the natural organs—or rather, it involves the problem of a progressively more complicated use of the latter—and hence stimulates a new line of development.
Roughly speaking, the use of such intervening appliances marks off games and work on one side, from play on the other. For a time children are satisfied with such changes as they can bring about with their hands and by locomotion and transportation. Other changes which they cannot so effect they are satisfied to imagine, without an actual physical modification. Let us "play"—let us "make-believe" that things are so and so, suffices. One thing may be made to stand for another, irrespective of its actual fitness. Thus leaves become dishes, bright stones articles of
