HABIT (from Lat. habitus, condition, from habere, to hold). In its most extended sense, a settling of any plastic material into determinate form. Since the organism at large, and the ner vous system in particular, are characterized by nothing so much as by plasticity, more especially during the years of growth that precede maturity, it is clear that habit must play an important part in biology, as well as in the sciences of mind (psychology, ethics) that follow upon bi ology. Habit, in this technical sense, is common both to man and to the lower animals. It may be defined as 'a fixed tendency,' the result of repetition and association, "to think, feel, or act in a particular way under special circumstances" (Sully). Habit finds its principal importance in the sphere of voluntary action, where it pre sents two points of psychological interest. In the first place, it "simplifies the movements required, to achieve a given result, makes them more ac curate, and diminishes fatigue." In the second place, it "diminishes the conscious attention with which our acts are performed" (James). Phys iologically regarded, habit thus implies that ner vous functions are relegated by the higher to the lower (automatic) centres; the cortex is relieved of so many burdens, and is free for so many new combinations. Psychologically re
garded, it implies the possibility of mental prog ress: what we have learned becomes a matter of course with us, unconsciously utilized when the right cue is given, so that we can drop, without fear of forgetting, the topic that we have been working upon, and proceed to new acquisitions upon the organized basis of previous effort.
It is important to distinguish accurately be tween `habit,' custom,"usage,' and 'fashion.' Habit is the widest term; it "covers all and every form of voluntary action that we have made our own" (Mundt). Habit is therefore an individual rule of conduct. Usage is social habit: there are family usages, local usages, etc.; but we do not speak of an individual usage. Custom• is habit, by virtue of its regularity and unifor mity; it is also usage, by virtue of its social or common character. But it is, further, normative in nature: it exercises a moral constraint; we may disobey it, as we may disregard the moral laws proper, but we do so at the risk of being considered 'eccentric,' if of nothing worse. Fash ion is an individual habit which has acquired a temporary vogue.