CHAPTER X
ASSOCIATION
Whence came the thought that occupies you this moment, and what determines
the next that is to follow? Introspection reveals no more interesting fact
concerning our minds than that our thoughts move in a connected and orderly
array and not in a hit-and-miss fashion. Our mental states do not throng the
stream of consciousness like so many pieces of wood following each other at
random down a rushing current, now this one ahead, now that. On the contrary,
our thoughts come, one after the other, as they are beckoned or caused. The
thought now in the focal point of your consciousness appeared because it
sprouted out of the one just preceding it; and the present thought, before it
departs, will determine its successor and lead it upon the scene. This is to say
that our thought stream possesses not only a continuity, but also a unity; it has
coherence and system. This coherence and system, which operates in accordance
with definite laws, is brought about by what the psychologist calls association.
1. THE NATURE OF ASSOCIATION
We may define association, then, as the tendency among our thoughts to form
such a system of bonds with each other that the objects of consciousness are
vitally connected both (1) as they exist at any given moment, and (2) as they
occur in succession in the mental stream.
The Neural Basis of Association.—The association of thoughts—ideas, images,
memory—or of a situation with its response, rests primarily on a neural basis.
Association is the result of habit working in neurone groups. Its fundamental law
is stated by James as follows: "When two elementary brain-processes have been
active together or in immediate succession, one of them, on recurring, tends to
propagate its excitement into the other." This is but a technical statement of the
simple fact that nerve currents flow most easily over the neurone connections
that they have already used.
It is hard to teach an old dog new tricks, because the old tricks employ familiar,