tellation of our memories and ideas is determined at any
given moment not merely by processes of association but also by
processes of dissociation. Practical interests, sentiments, and
emotional outbursts--love, fear, and anger--are constantly interrupting
the logical and constructive processes of the mind. These forces tend to
dissolve established connections between ideas and disintegrate our
memories so that they rarely function as a whole or as a unit, but
rather as more or less dissociated systems.

The mere act of attention, for example, so far as it focuses the
activities upon a single object, tends to narrow the range of
associations, check deliberation, and, by isolating one idea or system
of ideas, prepares us to act in accordance with them without regard to
the demands of other ideas in the wider but now suppressed context of
our experience. The isolation of one group of ideas implies the
suppression of other groups which are inconsistent with them or hinder
the indicated action.

When the fundamental instinct-emotions are aroused, they invariably have
the effect of isolating the ideas with which they are associated and of
inhibiting the contrary emotions. This is the explanation of war. When
the fighting instincts are stirred, men lose the fear of death and the
horror of killing.

When an idea, particularly one that is associated with some original
tendency of human nature, is thus isolated in consciousness, the
tendency is to respond to it automatically, just as one would respond to
a simple reflex. This explains the phenomena of suggestion. A state of
suggestibility is always a pre-condition of suggestion, and
suggestibility means just such an isolation and dissociation of the
suggested idea as has been described. Hypnotic trance may be defined as
a condition of abnormal suggestibility, in which the subject tends to
carry out automatically the commands of the experimenter, "as if," as
the familiar phrase puts it, "he had no will of his own," or rather, as
if the will of the experimenter had been substituted for that of the
subject. In fact the phenomena of auto-suggestion, in which one obeys
his own suggestion, seems to differ from other forms of the same
phenomena only in the fact that the subject obeys his own commands
instead of those of the experimenter. Not only suggestion and
auto-suggestion, but imitation, which is nothing more than another form
of suggestion, are made possible by the existence o