In playful competition indirect conquest of an opponent is aimed at, since the effort is to show that one can perform the task better than another. In it the fighting instinct assumes the form of rivalry. “No entreaties or commands,” says Lazarus, “nor even tips, could arouse our coachman to such a display of skill and speed as could another coachman who showed a disposition to race with him. Apart from the fighting instinct itself, jealousy is the prime cause of rivalry”. Spinoza defines it as “the desire for a thing aroused in us by the belief that others want it.” One of the first manifestations of jealousy in children is with regard to the love and caresses of its parents; we all know at what an early age the infant expresses his disapproval when his mother pets another child—sometimes as early as the second quarter. If he shows it simply as anger he is plainly jealous, as older children are; but if (as a dog often does when the hand he loves strokes another) he tries to win to himself by all sorts of cajoleries the maternal tenderness, then he enters upon a sort of rivalry. True emulation, however, is first developed when the aim is to win approbation and admiration when praise rather than love is the alluring reward—in short, when the child becomes ambitious. Say to a three- or four-year-old boy, “Your friend Otto can draw beautifully,” and it is ten to one that he will answer, “But I can draw better.” This desire to surpass others is what leads to the indirect contest which we call rivalry. Imitation, too, plays the part of a first cause here, as Spinoza points out in pursuance of his definition of emulation. As, however, this subject will come up for discussion later, let it suffice to say here that imitation is exceedingly important for all mental and physical development, and is accordingly especially conspicuous in the play of children. The effort to say “I can, too,” easily takes on a certain hostile character when there is difficulty in attainment, and so imitation becomes actual rivalry as soon as the effort is for “I can do better,” and the struggle becomes sharper in proportion to the consciousness of a desire to surpass. Thus we are justified in regarding the impulse of jealousy which is related to the fighting instinct as the foundation of rivalry as well.