When some years ago, the American public was confronted with the
striking exhibitions of muscle-reading, the wildest speculations were
indulged in regarding its true _modus operandi_; and the suggestion
that all that was done was explicable by the skillful interpretation
of the unconscious indications given by the subjects, was scouted
or even ridiculed. It was not supposed that such indications were
sufficiently definite for the purposes of the "mind-reader," or were
obtainable under the conditions of his tests. Again, it was urged
that this explanation was hardly applicable to certain striking
performances, which in reality involved other and subtler modes
of thought-interpretation, and the accounts of which were also
exaggerated and distorted. And furthermore, it was argued, too many
worthy and learned persons were absolutely certain that they had
given no indications whatever. For a time the view that mind-reading
was muscle-reading rested upon rather indirect evidence, and upon
a form of argument that carries more weight with those familiar
with the nature of scientific problems than with the public at
large. But the development of experimental research in the domain
of psychology has made possible a variety of demonstrations of the
truth and adequacy of this explanation. It was with the purpose of
securing a visible record of certain types of involuntary movements,
that the investigation, the results of which are here presented, was
undertaken.
[Illustration: FIG. 1.--THE AUTOMATOGRAPH. When in use
a screen (not shown in the illustration) cuts off the
view of the apparatus from the subject. The recording
device, which may also be used separately, is shown in
outline in half its full size. R is a glass rod which
moves freely up and down in the glass tube T, which is
set into the cork C. A rubber band B is provided to
prevent the rod from falling through the tube, when not
resting upon the recording-plate.]
Inasmuch as the movements in question are often very slight, somewhat
delicate apparatus is required to secure their record; the apparatus
must in a measure exaggerate the tendency to motion though without
altering its nature. The form of apparatus which I devised for this
study, and which may be appropriately called an automatograph, is
illustrated in the accompanying figure (p. 310). It consists of a
wooden frame, enclosing a heavy piece of plate glass (fifteen inches
square), and mounted upon three legs which are provided with screw
adjustments for bringing the plate into a perfect level. Upon the
plate of glass are placed in the form of a triangle three well turned
and polished steel or brass balls; and upon the balls rests a thin
crystal-plate glass set in a light wooden frame. The finger-tips of
one hand rest upon the upper plate in the position indicated. When
all is properly adjusted and glass and balls are rubbed smooth with
oil, it is quite impossible to hold the apparatus perfectly still for
more than a few seconds; the slightest unsteadiness or movement of
the hand at once sets the plate rolling with an irregular motion. If
one closes the eyes and fixes the attention upon a definite mental
image or train of thought, it is easy to form the conviction that
the plate remains quiet, but the record proves that this is not the
case. The other parts of the apparatus are designed to give a record
of the movements of the plate. Fastened to the light frame containing
the upper glass plate is a slender rod some ten inches long, bearing
at its end a cork; and piercing the cork is a small glass tube within
which a snugly fitting glass rod has room to move. The rod is drawn
to a smooth, round point; and when in position rests upon a piece of
glazed paper that has been blackened over a flame and then smoothly
stretched over a small glass plate. The point of the rod thus records
easily and accurately every movement of the hand that is imparted to
the upper plate, and by the manner of its adjustment accommodates
itself to all irregularities of movement or recording surface. This
recording device is shown in greater detail in the illustration, and
was used to good advantage as a simple automatograph in independence
of the balls and plates. In that case the recording part is held in
the hand as though it were a pencil, but in a vertical position, and
the record plate may be placed upon a table; or for special purposes
the plate may be held in the other hand or fastened to the top of
one's head. When not otherwise stated, the records here reproduced
were obtained by use of the automatograph. Some of the records are
noted as having been secured with the simpler device just described.
The process of securing a record is as follows: the subject,
standing, places his hand upon the automatograph, with the arm nearly
horizontal and not quite fully extended, and the elbow bent in a
fairly comfortable posture; his attention is engaged by asking him
to listen to and count the strokes of a metronome; to look at and
count the oscillations of a pendulum; to read from a book; to call
out the names of colors; to think of a given direction or locality,
or the position of an object; and so on. He is instructed to think as
little as possible of his hand, making a reasonable effort to keep
it from moving. To cut off the apparatus from the subject's field of
vision and attention, a large screen is interposed between him and
the record, a curtain with a suitable opening for the arm forming
part of the screen. The operator holds the glass pencil in his hand,
and when all is in readiness allows it to slip through the glass tube
and begin to write, removing it again after a definite interval or
when the record seems completed.