association we could have no memory. Let us see in a simple illustration how
association works in recall. Suppose you are passing an orchard and see a tree
loaded with tempting apples. You hesitate, then climb the fence, pick an apple
and eat it, hearing the owner's dog bark as you leave the place. The
accompanying diagram will illustrate roughly the centers of the cortex which
were involved in the act, and the association fibers which connect them. (See
Fig. 18.) Now let us see how you may afterward remember the circumstance
through association. Let us suppose that a week later you are seated at your
dining table, and that you begin to eat an apple whose flavor reminds you of the
one which you plucked from the tree. From this start how may the entire
circumstance be recalled? Remember that the cortical centers connected with the
sight of the apple tree, with our thoughts about it, with our movements in getting
the apple, and with hearing the dog bark, were all active together with the taste
center, and hence tend to be thrown into activity again from its activity. It is easy
to see that we may (1) get a visual image of the apple tree and its fruit from a
current over the gustatory-visual association fibers; (2) the thoughts, emotions,
or deliberations which we had on the former occasion may again recur to us
from a current over the gustatory-thought neurones; (3) we may get an image of
our movements in climbing the fence and picking the apple from a current over
the gustatory-motor fibers; or (4) we may get an auditory image of the barking of
the dog from a current over the gustatory-auditory fibers. Indeed, we are sure to
get some one or more of these unless the paths are blocked in some way, or our
attention leads off in some other direction.
Factors Determining Direction of Recall.—Which of these we get first, which
of the images the taste percept calls to take its place as it drops out of
consciousness, will depend, other things being equal, on which center was most
keenly active in the original situation, and is at the moment most permeable. If,
at the time we were eating the stolen fruit, our thoughts were keenly self-
accusing for taking the apples without permission, then the current will probably
discharge through the path gustatory-thought, and we shall recall these thoughts
and their accompanying feelings. But if it chances that the barking of the dog
frightened us badly, then more likely the discharge from the taste center will be
along the path gustatory-auditory, and we shall get the auditory image of the
dog's barking, which in turn may call up a visual image of his savage appearance
over the auditory-visual fibers. It is clear, however, that, given any one of the
elements of the entire situation back, the rest are potentially possible to us, and
any one may serve as a "cue" to call up all the rest. Whether, given the starting
point, we get them all, depends solely on whether the paths are sufficiently open