Page:Popular Science Monthly Volume 84.djvu/602

598 persistent striving of the organism toward an end, that end being usually some changed relation which shall subserve the life purposes of the individual. This striving has for its subjective correlate a state which we may characterize as tension, strain, stress or effort. It is this aspect of human behavior that constitutes work and distinguishes it from play. It is the power to hold oneself to a given task for the sake of a given end, to carry on an occupation even though it may have ceased to be interesting for the sake of some end to be gained other than the activity itself. This is work and it involves stress, strain, tension, effort, endeavor, concentration, application and inhibition, and is unconditionally the ground of progress. It is precisely the lack of this capacity for sustained and persevering effort that characterizes all uncivilized races.

Play is just the opposite and includes all activities in which the stress and strain are absent. Play is self-developing and supplies its own incentive. It is spontaneous and pleasant because of the sense of ease which accompanies it. Clearly play in this sense is something broader and more inclusive than those activities which we usually embrace under the term. It includes not merely children's plays and grown-ups' sports, not only hunting, fishing, boating, yachting, motoring, flying and all kinds of outing, not merely games and races and spectacles and tournaments and fairs and expositions, but also the theater and the opera, the enjoyment of music and painting and poetry, our daily paper and our magazines and our novels and our romances, and for that matter, many forms of so-called work in which the interest is self-developing, such, for instance, as gardening for pleasure. Relaxation or recreation would be perhaps more fitting terms to designate this large class of human activities.

All the evidence that we have points to the validity of the law that those peculiar forms of mental activity which have developed late in the evolution of man are most affected by fatigue—a law fully sustained by the study of psychasthenics and their incapacity for higher mental operations, as well as by the observation of people normally fatigued, while it is known that the disintegration of the nervous system in disease follows the reverse order of its development.

The application to the explanation of adult sport is evident. Those forms of mental activity which are developed late in the history of the race, and late in the life of the child, that tense and strenuous activity upon which modern progress depends, the power to hold ourselves by sustained attention and sustained effort down to hard and uninteresting tasks for the sake of some ultimate end, the concentration of the mental forces upon problems of science, philosophy and invention, and the inhibition of old and undesirable responses—all these bring quick and extreme fatigue and demand rest for the corresponding