sory currents into
outgoing motor currents.

So ingrained is this tendency toward movement that we do not need even
a sensory cue to start it off; an idea will do as well. In other words,
the nervous current need not start at a sense organ, but may start in
the brain and still produce movement. This fact is embodied in the law
of ideo-motor action (distinguished from sensory-motor action), "every
idea in the mind tends to express itself in movement." This motor
character of ideas is manifested in a most thorough-going way and
renders our muscular system a faithful mirror of our thoughts. We have
in the psychological laboratory delicate apparatus which enables us to
measure many of these slight movements. For example, we fasten a
recording device to the top of a person's head, so that his slightest
movements will be recorded, then we ask him while standing perfectly
still to think of an object at his right side. After several moments
the record shows that he involuntarily leans in the direction of the
object about which he is thinking. We find further illustration of this
law when we examine people as they read, for they involuntarily
accompany the reading with movements of speech, measurable in the
muscles of the throat, the tongue and the lips. These facts, and many
others, constitute good evidence for the statement that ideas seek
expression in movement.

The ethical consequences of this are so momentous that we must remark
upon them in passing. We now see the force of the biblical statement,
"Not that which entereth into the mouth defileth the man; but that
which proceedeth out of the mouth, this defileth the man." Think what
it means to one's character that every thought harbored in the mind is
bound to come out. It may not manifest itself at once in overt action,
but it affects the motor pathways and either weakens or strengthens
connections so that when the opportunity comes, some act will be
furthered or hindered. In view of the proneness to permit base thoughts
to enter the mind, human beings might sometimes fear even to think. A
more optimistic idea, however, is that noble thoughts lead to noble
acts. Therefore, keep in your mind the kind of thoughts that you wish
to see actualized in your character and the appropriate acts will
follow of their own accord.

But it is with the significance of expressions in study that we are at
present concerned, and here we find them of supreme importance. We
ordinarily reg