Evening star. [volume] (Washington, D.C.) 1854-1972, 1895-05-10
THE PENDULUM TIMER
An Instrument Invented for Measuring
Mental Time.
Constructed Under the Direction of
Prof. Edward w. Scripture, the
Psychologist.


describing the new apparatus called the
pendulum chronoscope, otherwise known
as the pendulum timer, said recently to
a Times representative: I'VE have often
heard the phrase, quick as thought Most
people think that is quicker than lightning
or quicker than nothing at all. But thought
takes time. as can be proved by expert
ments in the psychological laboratory.
How do We measure time of thought
and time of action? Let us start with
simple case. We have here piano player.
We will find out first whether he moves
his fingers at exactly the same time he
wills to move them. Let US put tele-
graph key under each of his hands. We
tell him to press both at exactly the same
time. He believes he does so. But to these
telegraph keys we have attached an appa-
ratus by which We get records in thou
sandths Of second. The piano player
sits at the left of the apparatus where the
test is to be made. A big spark coil with
batteries is connected with each key. and
with two metal points resting on a re-
volving drum. The drum is covered with
smoked paper. The moment each key Is
pressed spark is made from its pointer.
tuning fork is SO arranged that the dis
lance between these sparks is accorded in
thousandths of a second.
Test With 81 Piano Player.
1.-The first person on whom we tried this
experiment was well-known musician.
He. was sure both keys went down at ex-
actly the same time. The record showed
that his left hand was fifteen thousandths
of a second behind the right.
Let us advance one step further with
the piano player. He is to press the left
hand key when he hears base tone in a
telephone held to his ear He believes that
he presses the key exactly the same mo-
ment the tone comes In the laboratory
there Is en- arrangement by which record
is made on the drum at exactly the moment
the tone occurs in the telephone. The
other record is made by key. The record
shows that the moment of pressing the key
is away behind that of sounding the tone;
.2'D of second or one-ffth of a second is
very good average. This time is called
simple reaction time to sound
Let us give the piano player more
complicated problem. When he hears a
base tone he is to press the left-hand key.
When he hears high tone he Is to press
the rfght-hand key. Now. he has to dis
tinguish or discriminate between two things
and then to choose between two acts. You
can foresee the result. His time records
simple reaction time from these last rec
ords we get the actual time of performing
these two mental processes measured in
thousandths of a second.
I'm similar rlaDHer the PSYCHOLOGIST can
go through the whole domain of mental life
in regard to the time it occupies. For ex-
ample, suppose We wish to measure the
time 1t takes to associate two ideas. The
eXperimenter shouts soma word, for eX-
ample, house into a telephone which car
ries the word to another person in a dis
tant room. This other person shouts back
the first thing he thinks of, for example,
street These two telephones are SO rugged
up that they make records on the drum
where these words are shouted. Now the
time between the actual shouting of the
word house and that of the word street
represents the time lost by the mental proc
esses that were going on in the second per-
son.
The New Instrument.
What has been done for sound in these
experiments just described is also done in
a similar way for sight, touch, etc. This
graphic method is too complicated for use
outside OF the laboratory. The operation
for taking records of mental times has
hitherto been very complicated To over
come this difficulty a new instrun ent has
been invented in the Yale laboratory. 1t IS
call the pendulum timer.
"a very accurately swinging pendulum Is
so arranged that to a person sitting just
behind cloth banner hung on the instru-
ment a color is suddenly shown as PEN
dulum swings along. The person presses a
button and this catches L light pointer at
tached to the pendulum On scale in
front the exact distance travelled by the
pendulum from the moment the color was
shown to the moment the person pressed
the button can De read off in thousandths
of a second. This gives the time of the
simple reactions for sight by using two col
ors, for only one of which the person
presses the button. The mental processes
of Discrimination and choice are added to
the simple reaction. The time becomes
longer. Substract the simple reaction time
and you get the time occupied by those two
mental processes, discrimination and choice.
When three colors are used the time Is still
longer. So on, for more. Or you can use
letters, figures, words. Thus we have
THE apparatus was constructed particu-
larry for psychological purposes, but it IS
readily available for all cases where in
tervals of time less than e second are to be
measured, such as the speed of a rife ball
or of a cannon ball. The apparatus con-
sists of q triangular iron base about foot
wide, nickel plated, supported by three adj
Unstable legs. An upright bar carries a
heavy pendulum with a bob below and one
above. Behind the pendulum hangs silk
banner to hide the apparatus from the per-
son experimental upon. Behind the banner
is small knob. The pendulum is caught
to one side by fine catch. Some one re-
leases this catch, 1t starts to swing, and at
a certain point 1t lets fly a shutter like
photograph shutter. This shutter exposes
whatever the person is to see. At exactly
the same moment it catches fine pointer
and carries 1t along. The whole apparatus
stands about three feet high"
IN CONFEDERATE PRISONS.