Various forms of statement, most of them vague, have been and would be used in describing the potency of a perceived response, a thought-of response, or a train of inference, to produce a response and bind it to the given total situation. Any forms will do for the present argument, since all forms mean to assert that responses can be and often are bound to situations otherwise than by original bodily nature, satisfaction, discomfort, disuse and use. I shall try to show that they cannot; that, on the contrary, the laws of exercise and effect account for all learning. _The facts of imitation in human and animal behavior are explainable by the laws of instinct, exercise and effect._ Some cases of imitation are undoubtedly mere instincts in which the situation responded to is an act by another of the same species. If the baby smiles at a smile, it is because of a special, inborn connection between that sight and that act,—he smiles at a smile for just the same reason that he draws down his mouth and wails at harsh words. At that stage of his life he does not imitate other simple acts. A man runs _with_ a crowd for the same reason that he runs _from_ a tiger. Returning a blow is no more due to a general tendency to imitate than warding it off is. Other cases of imitation are mere adjuncts to the ordinary process of habit-formation. In the first place, the act of another, or its result, may serve as a model by which the satisfyingness of one’s own responses are determined. Just as the touch and taste of food tells a baby that he has got it safely into his mouth, so the sound of a word spoken by another or the sight of another performing some act of skill tells us whether our pronunciation or technique is right or wrong. In the second place, the perception of another’s act may serve as a stimulus to a response whereby the situation is altered into one to which the animal responds from habit by an act like the one perceived. For example, the perception of another making a certain response (_A_) to a situation (_B_) may lead in me by the laws of habit to a response (_C_) which puts me in a situation (_D_) such that the response (_A_) is made by me by the laws of habit. Suppose that by previous training the act of taking off my hat (_A_) has become connected as response to the situation (_D_), ‘thought of hat off,’ and suppose that with the sight of others uncovering their heads (_A_) in church (_B_) there has, again by previous habituation, been connected, as response (_C_), ‘thought of hat off.’ Then the sight of others uncovering their heads would by virtue of the laws of habit lead me to uncover. Imitation of this sort, where the perception of the act or condition in another gives rise to the idea of performing the act or attaining the condition, the idea in turn giving rise to the appropriate act, is certainly very common.