Most of the older theories of play did not take into account these three facts, i.e., the identity in original nature of the roots of play and work; the fact that man’s original nature fits him for primitive not civilized society; the complexity of the situation—­response connection and its necessary variation with minor elements in the external situation and in the individual.  Earlier writers, therefore, felt the need of special theories of play.  The best known of these theories are, first, the Schiller-Spencer surplus energy theory; second, the Groos preparation for life theory; third, the G. Stanley Hall atavistic theory; fourth, the Appleton biological theory.  Each of the theories has some element of truth in it, for play is complex enough to include them all, but each, save perhaps the last, falls short of an adequate explanation.

Two facts growing out of the theory of play accepted by the last few paragraphs need further discussion.  First, the order of development in play.  The play activities must follow along the line of the developing instincts and capacities.  As the nerve tracts governing certain responses become ready to act, these responses become the controlling ones in play.  So it is that for a time play is controlled largely by the instinct of manipulation, at another time physical activity combined with competition is most prominent, at another period imagination controls, still later the puzzle-solving tendency comes to the point followed by all the games involving an intellectual factor.  This being true, it is not surprising to find certain types of play characterizing certain ages and to find that though the particular games may vary, there is a strong resemblance between plays of children of the same age all over the world.  It must not be forgotten, however, that the readiness of nerve tracts to function, and therefore the play responses, depends on other factors as well as maturity.  The readiness of other tracts to function; past experience and habits; the stimulus provided by the present situation; absence of competing stimuli; sex, health, fatigue, tradition—­all these and many more factors modify the order of development of the play tendencies.  Still, having these facts in mind, it is possible to indicate roughly the type of play most prominent at different ages.

Children from four to seven play primarily in terms of sensory responses, imagination, imitation, and curiosity of the cruder sort.  Love of rhythm also is strong at this period.  From seven to ten individual competition or rivalry becomes very strong and influences physical games, the collecting tendency, and manipulation, all of which tendencies are prominent at this time.  Ten to twelve or thirteen is characterized by the “gang” spirit which shows itself in connection with all outdoor games and adventures; memory is a large factor in some of the plays of this period, and independent thinking in connection with situations engendered by manipulation and the gang