在心理學的領域裡，行為和習慣是一個主要的論題；尤其在應用科學方法研究心理學以後，注重觀察和實驗；又為了觀察和實驗的便利，已動物為研究對象，所以不但有了比較心理學這一個科目，也有了品行學〈Etholegy〉這個名稱，在這個名稱中所包括的一項以人為研究主體的，當稱為「人性學」，但是多數研究者還是以動物為研究的對象。

Human behavior is a broad concept as man moves and acts everyday. Besides instinctive reflections, there are physical and mental activities. The former are external while the later internal. External activities can be observed directly but not the internal. However, both are dealt with in the scope of behavior in psychology.
Mental activities are main functions of the central nervous system. Even body movements are governed by the brain. Thus a behavior may be evoked either by an external or internal stimulus, while the central system is the general faculty. Behavior can be conditioned or reinforced by external effects; or it can be changed by a person himself. For these reasons that education can achieve certain extent to form or change a child’s behavior.
Habits are learned. It is a kind of behavior constantly occurs and becomes a stereotype. Some habits are concerned with basic needs in living; some are cultivated by a person consciously or unconsciously; still belong to intellectual functioning. From educational stand, habits are to be cultivated as they are considered good, i.e., they are beneficial to the person himself or to his cultural development. While the others are to be prohibited as they are considered bad because they are either harmful to the person of tabooed by his culture and society. As those which have neither profit nor impairment can be held by a person’s preference.
As habits are fixed behavior patterns, when such patterns formulate a person’s system, it may become a part of his personality. Thus in the processes of personality development, patents and teachers are responsible to a child’s habit cultivation.