words are grasped as
units. Notice that these units are our own units, not external units.
Physically, a row of six dots is as much a unit as a row of four, but
we grasp the four as a unit in a way that we cannot apply to the six.
Physically, six letters are as much a unit when they do not form a
word as when they do; but we can make a unitary response to the six in
the one case and not in the other. The response is a unit, though
aroused by a number of separate stimuli.

The law of combination, from its name, is open to a possible
misconception, as if we reached out and grasped and combined the
stimuli, whereas ordinarily we do nothing to the stimuli, except to
see them and recognize them, or in some such way respond to them. The
combination is something that happens _in us_; it is our response. If
the expression were not so cumbersome, we might more accurately name
this law that of "unitary response to a plurality of stimuli".

Sometimes, indeed, we do make an actual motor response to two or more
stimuli, as when we strike a chord of several notes on the piano. The
law of combination still holds good here, since the movements of the
two hands are cooerdinated into a single act, which is thought of as a
unit ("striking a chord"), attended to as a unit, and executed as a
unit. Such cooerdinated movements may be called "higher motor units",
and we shall find much to say regarding them when we come to the
subject of learned reactions. The law of combination, all in all, will
be found later to have extreme importance in learned reactions.

Passing now to another side of the study of attention, we shall
immediately come across a sixth law to add to our list.

{265}

Attention and Degree of Consciousness

Up to this point, the introspective side of the psychology of
attention has not been considered. One of the surest of all
introspective observations belongs right here, to the effect that we
are more conscious of that to which we are attending than of anything
else. Of two stimuli acting at once upon us, we are the more conscious
of that one which catches our attention; of two acts that we perform
simultaneously, that one is more conscious that is performed
attentively.

We need not be entirely unconscious of the act or the stimulus to
which we are not attending. We may be dimly conscious of it. There are
degrees of consciousness. Suppose, for example, you are looking out of
the window while "lost in thought". You