umber of diverse possible associative sequences. Professor Muensterberg
performed this experiment methodically, using the same words four times
over, at three-month intervals, as 'cues' for four different persons who
were the subjects of observation. He found almost no constancy in their
associations taken at these different times. In short, the entire
potential content of one's consciousness is accessible from any one of
its points. This is why we can never work the laws of association
forward: starting from the present field as a cue, we can never cipher
out in advance just what the person will be thinking of five minutes
later. The elements which may become prepotent in the process, the parts
of each successive field round which the associations shall chiefly
turn, the possible bifurcations of suggestion, are so numerous and
ambiguous as to be indeterminable before the fact. But, although we
cannot work the laws of association forward, we can always work them
backwards. We cannot say now what we shall find ourselves thinking of
five minutes hence; but, whatever it may be, we shall then be able to
trace it through intermediary links of contiguity or similarity to what
we are thinking now. What so baffles our prevision is the shifting part
played by the margin and focus--in fact, by each element by itself of
the margin or focus--in calling up the next ideas.

For example, I am reciting 'Locksley Hall,' in order to divert my mind
from a state of suspense that I am in concerning the will of a relative
that is dead. The will still remains in the mental background as an
extremely marginal or ultra-marginal portion of my field of
consciousness; but the poem fairly keeps my attention from it, until I
come to the line, "I, the heir of all the ages, in the foremost files of
time." The words 'I, the heir,' immediately make an electric connection
with the marginal thought of the will; that, in turn, makes my heart
beat with anticipation of my possible legacy, so that I throw down the
book and pace the floor excitedly with visions of my future fortune
pouring through my mind. Any portion of the field of consciousness that
has more potentialities of emotional excitement than another may thus be
roused to predominant activity; and the shifting play of interest now in
one portion, now in another, deflects the currents in all sorts of
zigzag ways, the mental activity running hither and thither as the
sparks run in burnt-up paper.