To get skill, then, one must practice. But mere repetition is not sufficient. For practice to be most effective, one must put his whole mind on what he is doing. If he divides his attention between the acts which he is practicing and something else, the effect of the practice in fixing and perfecting the habit is slight. It seems that when we are building up a new nerve-path which is to be the basis of a new habit, the nervous energies should not be divided; that the whole available nervous energy should be devoted to the acts which we are repeating. This is only another way of saying that when we are practicing to establish a habit, we should attend to what we are doing and to nothing else. But after the habit-connection is once firmly established, we can attend to other things while performing the habitual act. The habitual action will go on of itself. We may say, then, that in order to be able to do a thing with little or no attention, we must give much attention to it at first. Another important factor in habit-formation is pleasure. The act which we are practicing must give us pleasure, either while we are doing it or as a result. Pleasurable results hasten habit-formation. When we practice an act in which we have no interest, we make slow progress or none at all. Now the elements of interest are attention and pleasure. If we voluntarily attend to a thing and its performance gives us pleasure, or pleasure results from it, we say we are interested in it. The secret of successful practice is interest. Repeatedly in laboratory experiments it happens that a student loses interest in the performance and subsequently makes little, if any, progress. One of the biggest problems connected with habit-formation is that of maintaining interest. A factor which prevents the formation of habits is that of exceptions. If a stimulus, instead of going over to the appropriate response, produces some other action, there is an interference in the formation of the desired habit. The effect of an exception is greater than the mere neglect of practice. The _exception opens up another path_ and tends to make future action uncertain. Particularly is this true in the case of moral habits. Forming moral habits is usually uphill work anyway, in that we have instincts to overcome. Allowing exceptions to enter, in the moral sphere, usually means a slipping back into an old way of acting, thereby weakening much the newly-made connection. In any kind of practice, when we become fatigued we make errors. If we continue to practice when fatigued, we form connections which we do not wish to make and which interfere with the desired habits.