in consciousness is a matter of mechanical adjustment.  James describes consciousness by likening it to a series of waves, each having a crest and sides which correspond to the focus and margin of attention.  The form of the wave changes from a high sharp crest with almost straight sides in pointed, concentrated attention, to a series of mere undulations, when crests are difficult to distinguish, in so-called states of dispersed attention.  The latter states are rare in normal individuals, although they may be rather frequent in certain types of low-grade mental defectives.  This of course means that states of “inattention” do not exist in normal people.  So long as consciousness is present one must be attending to something.  The “day dream” is often accompanied by concentrated attention.  Only when we are truly thinking of nothing, and that can only be as unconsciousness approaches, is attention absent.  What is true of attention is also true of interest, for interest is coming more and more to be considered the “feeling side” of attention, or the affective accompaniment of attention.  The kind of interest may vary, but some kind is always present.  The place the interest occupies may also vary:  sometimes the affective state itself is so strong that it forces itself into the focal point and becomes the object of attention.  The chief fact of importance, however, is that attention and interest are inseparable and both are coexistent with consciousness.

This selective action of consciousness is mechanical, due to the inborn tendencies toward attention possessed by human beings.  The situations which by their very nature occupy the focal point in consciousness are color and brightness, novelty, sudden changes and sharp contrasts, rhythm and cadence, movement, and all other situations to which there are other instinctive responses, such as hunting, collecting, curiosity, manipulation, etc.  In other words, children are born with tendencies to attend to an enormous number of situations because of the number of instinctive responses they possess.  So great is this number that psychologists used to talk about the omnivorousness of children’s attention, believing that they attended to everything.  Such a general attention seems not to be true.  However, it is because so many situations have the power to force consciousness to a crest that human beings have developed the intellectual power that puts them so far above other animals.  That these situations do attract attention is shown by the fact that individuals respond by movements which enable them to be more deeply impressed or impressed for a longer time by the situations in question.  For example, a baby will focus his eyes upon a bright object and then move eyes and head to follow it if it moves from his field of vision.  Just what the situations are, then, which will arouse responses of attention in any given individual will depend in the first place upon his age, sex, and maturity, and in the second place upon his experience.  The process of learning very quickly modifies the inborn tendencies to attention by adding new situations which demand it.  It is the things we learn to attend to that make us human rather than merely animal.