The most fruitful field of this sort of imitative learning is in connection with the "try-try-again" struggles of the young, especially children. This is called Persistent Imitation. The child sees before him some action to imitate--some complex act of manipulation with the hand, let us say. He tries to perform it in an experimental way, using the muscles of the hand and arm. With this he strains himself all over, twisting his tongue, bending his body, and grimacing from head to foot, so to speak. Thus he gets a certain way toward the correct result, but very crudely and inexactly. Then he tries again, proceeding now on the knowledge which the first effort gave him; and his trial is less uncouth because he now suppresses some of the hindering grimacing movements and retains the ones which he sees to be most nearly correct. Again he tries, and again, persistently but gradually reducing the blundering movements to the pattern of the copy, and so learning to perform the act of skill. The massive and diffused movements which he makes by wriggling and fussing are also of direct use to him. They increase remarkably the chances that among them all there will be some movements which will hit the mark, and so contribute to his stock of correct Equivalents. Dogs and monkeys learn to unlock doors, let down fence rails, and perform relatively complex actions by experimenting; persistently with many varied movements until the successful ones are finally struck. This is the type of all those acts of experimenting by which new complex movements are acquired. In children it proceeds largely without interference from others; the child persists of himself. He has greater ability than the animals to see the meaning of the completed act and to really desire to acquire it. With the animals the acquisitions do not extend very far, on account of their limitation in intelligent endowment; but in the training of the domestic animals and in the education of show-animals the trainer aids them and urges them on by making use of the associations of pleasure and pain spoken of above. He supplements the animal's feelings of pain and pleasure with the whip and with rewards of food, etc., so that each step of the animal's success or failure has acute associations with pain or pleasure. Thus the animal gradually gets a number of associations formed, avoids the actions with which pain is associated, repeats those which call up memories of pleasure all the way through an extended performance in regular steps; and in the result the performance so closely counterfeits the operations of high intelligence--such as counting, drawing cards, etc.--that the audience is excited to admiration. This first glimpse of the animal's limitations when compared with man may suggest the general question, how far the brutes go in their intelligent endowment. The proper treatment of this much-debated point requires certain further explanations.