in
consciousness; or, in other words, the particular impression becomes a
clear-cut and definite experience.

[Illustration: Probable adjusting of nerve ends during active attention]

=Neural Basis of Attention.=--The neural conditions under which the mind
exercises such active attention seem to be that during the attentive
state the nervous energy concentrates itself upon the paths and centres
involved in the particular experience, the resistance being decreased in
the paths connecting the cells traversed by the impulse. Moreover, any
nervous energy tending to escape in other channels is checked and the
movements hindered, thus shutting off attention from other possible
experiences. For instance, a person with little interest in horticulture
might pass a flowering shrub, the colour, form, and scent making only a
faint impression upon him. If, however, his companion should say, "What
a lovely colour," his attention will direct itself to this quality, with
the result that the colour stands out much more clearly in
consciousness, and the other features practically escape his notice.
Here the suggestion of the companion focuses attention upon the colour,
this being accompanied with a lessening of the resistance between the
centres involved in interpreting the colour sensations. At the same time
resistance in the arcs involving form and smell is increased, and the
energy diverted from these arcs into that of colour.

ATTENTION SELECTIVE

=Attention and Interest.=--At this point a question naturally arises why
the mind, since it is continually subject to the influence of
impressions from without and of reviving ideas from within, should
select and focus attention upon certain of these to the exclusion of
others. The answer usually given is that the mind feels in each case, at
least vaguely, a personal interest in some change or adjustment to be
wrought either in or through the impression which it makes an object of
attention. When, for instance, the reader diverts his attention from the
interesting story to the loud talking outside the window, he evidently
desires to adjust his understanding more fully to the new and strange
impression. So, also, when the spectator rivets his attention upon the
flying ball, it is because he associates with this the interesting
possibility of a change in the score. In like manner, the student in
geometry fixes his attention upon the line joining the points of
bisection of the sides, bec