New-York tribune., 1919-02-23
What's Your
Speed?
UTE some food for thought is
offered in Ernest Welleck's ar
- ticle in current issue of "Pop-

ular Science" entitled "What's
Your Speed?" This question, as Mr..
Welleck considerably points out, does
not apply to your car (if you have one),
but to your brain. The writer asks:
"How promptly does your brain respond
to impressions by muscular reaction?"
And then he says:
'H you don't know, and the chances are
you don't, 60 to DR.. Amar, in Paris, and
let him find out for you. He will submit
you to few Photographic tests, and at
their conclusion will tell you your speed to
the hundredth part of second. Incident
ally, he will tell you whether you are fitted
for the profession or occupation in which
you are engaged or intend to become en-
gagged.
"The apparatus that DR.. Amar uses is a
psychograph OF his own invention, device
for registering the promptness, intensity
duration, ETC., Of muscular responses to
Impressions received by eye, ear, or sense
Of touch of the person tested. The appar
stus has a cylinder covered with paper
coated with lampblack
"This cylinder is revolved by clockwork
at the rate of one revolution second. A
vibrating needle, which makes one hundred
double vibrations q second, marks a wavv
line that serves as time measure for minute
fractions of second upon the blackened
80
ject tested are transmitted by air pressure
to two needles, which mark q record of
these reactions on the cylinder.
"Dr. Amar will seat you in front of a
table equipped with the testing apparatus.
Directly before you are two little pneumatic
drums When you have received your
instructions you place a finger upon the
membrane Of one of the little drums, your
eyes focused on something that resembles
small camera.
"A few minutes later a touch of the
doctors finger upon the shutter releases
allows flash of the electric light in the
box behind the lens to reach your eve, At
the same moment-so it seems to you-you
press your finger upon the drum head. The
air pressure in the drum simultaneously
causes needle to mark line, more or less
curved, on the lampblack covered paper
"Then the paper is taken off the cylinder
Here is the mark of the doctors signal and
there is the record of your reaction. The
doctor counts the number of waves of the
vibrating needle on the paper and informs
you that 20/100 Of second elapsed between
the signal and your response. And you
imagined your pressure to have been
simultaneous with the signal
"You are assured that your brain func-
tions normally-that the time for simple
visual reactions in normal subjects averages
between 0.l95 and 0.21 seconds
I'm the tests for reactions involving oe-
liberation the same device is used You
place finger of the left hand on one
OF the LITTLE drums one finger of the right
hand on the other drum. You are informed
that the left drum means blue, the right
drum red. The doctor flashes q red or
blue light through the lens of the camera
Ike device, and you signal back the impress
sion by pressing the right or the left drum
head. On examining the record on the CYL
inder you find that it took you more than
twice as long to react in this visual test as
IN the simple visual test in which you were
not called upon to decide whether the light
was red or blue
The statistical material so far collected
SHOWS that the age of the subject, between
the limits of eighteen and forty-fve years,
does not materially affect the time of simple
reactions. Subjects whose occupation de-
mancs alertness - for instance, designers,
Vpists and mechanics-react more promptly
'han farmers, who invariably slower by
wv seconds or more. The records of per-
sons who have sustained injuries of the
0rain' or who have been operated on be-
cause Of such injuries, show much higher