THE ADJUSTMENT OF TECHNICAL TO PSYCHICAL CONDITIONS
Teaching and learning represent only
the preliminary problem. The fundamental question
remains, after all, how the work is to be done by
those who have learned it in accordance with the customs
of the economic surroundings and who are accordingly
already educated and trained for it. What can
be done to eliminate everything which diminishes and
decreases efficiency, and what remains to be done to
reinforce it. Such influences are evidently exerted
by the external technical conditions, by variations
of the activity itself, and by the play of the psychical
motives and counter-motives. It must seem as if
only this last factor would belong in the realm of
psychology, but the technical conditions, of which
the machine itself is the most important part, and
the bodily movements also have manifold relations
to the psychical life. Only as far as these relations
prevail has the psychologist any reason to study the
problem. The purely physical and economic factors
of technique do not interest him at all, but when a
technical arrangement makes a psychophysical achievement
more difficult or more easy, it belongs in the sphere
of the psychologist, and just this aspect of the work
may become of greatest importance for the total result.
In all three of these directions, that is, with reference
to the technical, to the physiological, and to the
purely psychical, the scientific management movement
has prepared the way. The engineers of scientific
management recognized, at least, that no part of the
industrial process is indifferent, even the apparently
most trivial activity, the slightest movement of arm
or hand or leg, became the object of their exact measurement.
The stopwatch which measures every movement in fractions
of a second has become the symbol of this new economic
period. As long as special psychological experiments
in the service of industrial psychology are still so
exceptional, it may, indeed, be acknowledged that the
practical experiments in the service of scientific
management have come nearest to the solution of these
special psychotechnical problems.
To proceed from without toward the
centre, we may begin our review with the physical
technique of the working conditions and its relations
to the mind. Tue history of technique shows on
every page this practical adjustment of external labor
conditions to the psychophysical necessities and psychophysical
demands. No machine with which a human being
is to work can survive in the struggle for technical
existence, unless it is to a certain degree adapted
to the human nerve and muscle system and to man’s
possibilities of perception, of attention, of memory,
of feeling, and of will. Industrial technique
with its restless improvements has always been subordinated
to this postulate. Every change which made it
possible for the workingman to secure equal effects
with smaller effort or to secure greater or better
effects with equal effort counted as an economic gain,
which was welcome to the market. For instance,
throughout the history of industry we find the fundamental
tendency to transpose all activities from the great
muscles to the small muscles. Any activity which
is performed with the robust muscles of the shoulder
when it can be done with the lower arm, or labor which
is demanded from the muscles of the lower arm when
it can just as well be carried out by the fingers,
certainly involves a waste of psychophysical energy.
A stronger psychophysical excitement is necessary
in order to secure the innervation of the big muscles
in the central nervous system. This difference
in the stimulation of the various muscle groups has
been of significant consequence for the differentiation
of work throughout the development of mankind.
Labor with the large muscles has, for these psychophysical
reasons, never been easily combined with the subtler
training of the finer muscles. Hence a social
organization which obliged the men to give their energy
to war and the hunt, both, in primitive life, functions
of the strongest muscles, made it necessary for the
domestic activities, which are essentially functions
of the small muscles, to be carried out by women.
The whole history of the machine demonstrates this
economic tendency to make activities dependent upon
those muscles which presuppose the smallest psychophysical
effort. It is not only the smaller effort which
gives economic advantage to the stimulation of the
smaller muscles, but the no less important circumstance
that the psychophysical after-effect of their central
excitement exerts less inhibition than the after-effect
of the brain excitement for the big muscles.
But we must not overlook another feature
in the development of technique. The machines
have been constantly transformed in the direction
which made it possible to secure the greatest help
from the natural cooerdination of bodily movements.
The physiological organization and the psychophysical
conditions of the nervous system make it necessary
that the movement impulses flow over into motor side
channels and thus produce accessory effects without
any special effort. If a machine is so constructed
that these natural accessory movements must be artificially
and intentionally suppressed, it means, on the one
side, a waste of available psychophysical energy, and
on the other side it demands a useless effort in order
to secure this inhibition. The industrial development
has moved toward both the fructification of those
side impulses and the avoidance of these inhibitions.
It has adjusted itself practically to the natural
psychical conditions. Ultimately it is this tendency
which shaped the technical apparatus for the economic
work until the muscle movements could become rhythmical.
The rhythmical activity necessarily involves a psychophysical
saving and this saving has been instinctively secured
throughout the history of civilization. All rhythm
contains a repetition of movement without making a
real repetition of the psychophysical impulse necessary.
In the rhythmical activity a large part of the first
excitement still serves for the second, and the second
for the third. Inhibitions fall away and the mere
after-effect of each stimulus secures a great saving
for the new impulse. The history of the machine
even indicates that the newer technical development
not only found the far-reaching division of labor already
in the workshops of earlier centuries, but a no less
far-reaching rhythmization of the labor in fine adaptation
to the needs of the psychophysical organism, long
before the appearance of the machines. The beginnings
of the machine period frequently showed nothing but
an imitation of the rhythmical movements of man.
To be sure, the later improvements of the machine
have frequently destroyed that original rhythm of
man’s movement, as the movement itself, especially
in the electric machines, has become so quick that
the subjective rhythmical experience has been lost.
Moreover, the rhythmical horizontal and vertical movements
were for physical reasons usually replaced by uniform
circular movements. But even the most highly
developed machine demands human activity, for instance,
for the supplying with material; and this again has
opened new possibilities for the adjustment of technical
mechanism to the economic demand for rhythmical muscle
activity. The growth of technical devices has
thus been constantly under the control of psychological
demands, in spite of the absence of systematic psychological
investigations. But the decisive factor was,
indeed, that these psychological motives always remained
in the subconsciousness of civilization. The improvements
were consciously referred to the machine as such, however
much the practical success was really influenced by
the degree of its adjustment to the mental conditions
of the workingmen. The new movements of scientific
management and of experimental psychology aim toward
bringing this adaptation consciously into the foreground
and toward testing and studying systematically what
technical variations can best suit the psychophysical
status of man.
Those who are familiar with the achievements
of scientific management remember that by no means
only the complicated procedures on a high level are
in question. The successes are often the most
surprising where the technique is old, and where it
might have been imagined that the experiences of many
centuries would have secured through mere common sense
the most effective performance. The best-known
case is perhaps that of the masons, which one of the
leaders of the scientific management movement has
studied in all its details. The movements of the
builders and the tools which they use were examined
with scientific exactitude and slowly reshaped under
the point of view of psychology and physiology.
The total result was that after the new method 30
masons completed without greater fatigue what after
the old methods it would have taken 100 masons to
do, and that the total expense for the building was
reduced to less than a half in spite of the steady
increase of the wages of the laborers. For this
purpose it was necessary that exact measurements be
made of the height at which the bricks were lying
and of the height of the wall on which they must be
laid, and of the number of bricks which should be carried
to the masons at once. He studied how the trowel
should be shaped and how the mortar should be used
and how the bricks should be carried to the bricklayers.
In short, everything which usually is left to tradition,
to caprice, and to an economy which looks out only
for the most immediate saving, was on the basis of
experiments of many years replaced by entirely new
means and tools, where nothing was left to arbitrariness.
Yet these changes did not demand any invention or
physically or economically new ideas, but merely a
more careful adaptation of the apparatus to the psychological
energies of the masons. The new arrangement permitted
a better organization of the necessary bodily movements,
fatigue was diminished, the accessory movements were
better fructified, fewer inhibitions were necessary,
a better playing together of the psychical energies
was secured.
The students of scientific management
stepped still lower in the scale of economic activity.
There is no more ordinary productive function than
shoveling. Yet in great establishments the shoveling
of coal or of dirt may represent an economically very
important factor. It seems that up to the days
of scientific management, no one really looked carefully
into the technical conditions under which the greatest
possible economic effect might be reached. Now
the act of shoveling was approached with the carefulness
with which a scholar turns to any subtle process in
his laboratory. The brilliant originator of the
scientific management movement, who carried out these
investigations in the great Bethlehem Steel Works,
where hundreds of laborers had to shovel heavy iron
ore or light ashes, found that the usual chance methods
involve an absurd economic waste. The burden was
sometimes so heavy that rapid fatigue developed and
the movements became too slow, or the lifted mass
was so light that the larger part of the laborer’s
energies remained unused. In either case the final
result of the day’s work must be anti-economic.
He therefore tested with carefully graded experiments
what weight ensured the most favorable achievement
by a strong healthy workingman. The aim was to
find the weight which would secure with well-arranged
pauses the maximum product in one day without over-fatigue.
As soon as this weight was determined, a special set
of shovels had to be constructed for every particular
kind of material. The laborers were now obliged
to operate with 10 different kinds of shovels, each
of such a size that the burden always remained an
average of 21 pounds for any kind of material.
The following step was an exact determination of the
most favorable rapidity and the most perfect movement
of shoveling, the best distribution of pauses, and
so on, and the final outcome was that only 140 men
were needed where on the basis of the old plan about
500 laborers had been engaged. The average workingman
who had previously shoveled 16 tons of material, now
managed 59 tons without greater fatigue. The
wages were raised by two thirds and the expenses for
shoveling a ton of material were decreased one half
This calculation of expenses included, of course,
a consideration of the increased cost for tools and
for the salaries of the scientific managers.
Whoever visits factories in which
the new system has been introduced by real specialists
must be surprised, indeed, by the great effects which
often result from the better psychophysical adaptation
of the simplest and apparently most indifferent tools
and means. As far as the complicated machines
are concerned, we are accustomed to a steady improvement
by the efforts of the technicians and we notice it
rather little if the changes in them are introduced
for psychological instead of the usual physical reasons.
But the fact that even the least complicated and most
indifferent devices can undergo most influential improvements,
as soon as they are seriously studied from a psychological
point of view, remains really a source for surprise.
Sometimes no more is needed than a change in the windows
or in the electric lamps, by which the light can fall
on the work in a psychologically satisfactory way;
sometimes long series of experiments have to be made
with a simple hammer or knife or table. Often
everything must be arranged against the wishes of the
workingmen, who feel any deviation from the accustomed
conditions as a disturbance which is to be regarded
with suspicion. In one concern I heard that the
scientific manager became convinced that all the working-chairs
for the women were too low and that the laborers therefore
had to hold their arms in a psychophysically unfavorable
position during the handling of the apparatus.
All were strongly opposed to the introduction of higher
chairs. The result was that the manager arranged
for the chairs to be raised a few millimeters every
evening, without the knowledge of the working-women,
as soon as the factory was empty. After a few
weeks the chairs had reached the right height without
those engaged in the work having noticed it at all.
The outcome was a decided increase of efficiency.
But the most rational scheme will
after all be to prepare for such arrangements of tools
and apparatus by systematic experiments in the psychological
laboratory. The subtlety of such investigations
will lead far beyond the point which is accessible
to the attempts of scientific management. Exact
experiments on attention, for instance, will have
to determine how the various parts of the apparatus
are to be distributed best in space if the laborer
must keep watch for disturbances at various places.
Only the laboratory experiment can find the most favorable
speed of the machine or can select the muscles to
which the mind can send the most effective impulses.
The construction of the machine must then be adapted
to such results. In the Harvard laboratory, for
instance, a practical question led us to examine which
fingers would allow the quickest alternation of key
movements. If any two of the ten fingers perform
for ten seconds the quickest possible alternation
of motion, as in a trill, the experiment can demonstrate
exactly the differences between the various combinations
of fingers and the individual fluctuations for these
differences. With an electrical registration of
the movements of the alternating fingers we studied
in hundredths of a second the time for the motions
of two hands and of fingers of the same hand, in order
to adjust the keys of a certain machine to the most
favorable impulses.
We approach this group of problems
from another side when we test the relations of various
kinds of machines to various mental types. Psychologists
have studied, for example, the various styles of typewriting
machines. From a purely commercial point of view
the merits of one or another machine are praised as
if they were advantageous for every possible human
being. The fact is that such advantages for one
may be disadvantages for another on account of differences
in the mental disposition. One man may write more
quickly on one, another on another machine. As
every one knows, the chief difference is that of the
keyboard and that of the visible or invisible writing.
Machines like the Remington machine work with a shift
key; that is, a special key must be pressed when capital
letters are to be written. Other machines like
the Oliver even demand double shifting, one key for
the capital letters, and one for the figures, and
so on. On the other hand, machines like the Smith
Premier have no shift key, but a double keyboard.
It is evident that both the shift-key arrangement
and the double keyboard have their particular psychological
advantages.
The single alphabet demands much less
from the optical memory, and the corresponding motor
inner attitude of consciousness is adjusted to a smaller
number of possibilities. But the pressure on the
shift key, which goes with the single alphabet, is
not only a time-wasting act; from the psychological
point of view it is first of all a very strong interruption
of the uniform chain of impulses. If the capital
and small letters are written for a minute alternatingly
with the greatest possible speed, the experiment shows
that the number of letters for the machine with the
double alphabet is about three times greater than
for the machine with simple alphabet and shift key.
Both systems accordingly have their psychological
advantages and disadvantages. Human beings of
distinct visual ideational type or of highly developed
motor type will prefer the double alphabet, provided,
of course, that the touch system of writing is learned,
and this will be especially true if their inner attitude
is easily disturbed by interruptions. But those
who have a feebly developed optical mental centre and
who have small ability for the development of complex
motor habits will be more efficient on the machines
with the single alphabet, especially if their nervous
system is little molested by interruptions and thus
undisturbed by the intrusion of the shift key act.
In a similar way the visibility of
the writing will be for certain individuals the most
valuable condition for quick writing, while for others,
who depend less upon visual support, it may mean rather
a distraction and an interference with the speediest
work. The visible writing attracts the involuntary
attention, and thus forces consciousness to stick
to that which has been written instead of being concentrated
on that which is to be produced by the next writing
movements. The operator himself is not aware of
this hindrance. On the contrary, the public will
always be inclined to prefer the typewriters with
visible writing, because by a natural confusion the
feeling arises that the production of the letter is
somewhat facilitated, when the eye is cooeperating,
just as in writing with a pen we follow the lines
of the written letter. But the situation lies
differently in the two cases. When we are writing
with a pen, the letter grows under our eyes, while
in the machine writing we do not see any part of the
letter until the whole movement which produces the
single letter is finished. By such a misleading
analogy many a man is led to prefer the typewriter
with visible writing, while he would probably secure
a greater speed with a machine which does not tempt
him to attend the completed letters, while his entire
attention ought to belong to the following letters.
These last observations point to another
psychological aspect of the machine and of the whole
technical work, namely, their relations to the impressions
of the senses. The so-called dynamogenic experiments
of the psychological laboratory have demonstrated what
a manifold influence flows from the sense-impressions
to the will-impulses. If the muscle contraction
of a man’s fist is measured, the experiment
shows that the strongest possible pressure may be very
different when the visual field appears in different
colors, or tones of different pitch or different noises
are stimulating the ear, and so on. As yet no
systematic experiments exist by which such results
can be brought into relation to the sense-stimuli
which reach the laborer during his technical work.
The psychophysical effect of colors and noises has
not been fructified at all for industrial purposes.
The mere subjective judgment of the workingman himself
cannot be acknowledged as reliable in such questions.
The laborer, for instance, usually believes that a
noise to which he has become accustomed does not disturb
him in his work, while experimental results point
strongly to the contrary. In a similar way the
effect of colored windows may appear indifferent to
the workmen, and yet may have considerable influence
on his efficiency. Numberless performances in
the factory are reactions on certain optical or acoustical
or tactual signals. Both the engineer and the
workman are satisfied if such a signal is clearly perceivable.
The psychological laboratory experiment, however, shows
that the whole psychophysical effect depends upon
the character of the signal; a more intense light,
a quicker change, a higher tone, a larger field of
light, a louder noise, or a harder touch may produce
a very different kind of reaction.
With a careful time-measurement of
the motions, it can often be directly traced how purely
technical processes in the machine itself influence
and control the whole psychical system of impulses
in the man. I observed, in a factory, for instance,
the work at a machine which performed most of its
functions automatically. It had to hammer fine
grooves into small metal plates. A young laborer
stood before every such machine, took from a pile,
alternately from the right and from the left, the
little plates to be serrated, placed them in the machine,
turned a lever to bring the hammer into motion, and
then removed the serrated plates. The speed of
the work was dependent upon the operative, as he determined
by his lever movement the instant at which the automatic
serrating hammer should be released. The man’s
activity demanded 9 independent movements. I found
that those who worked the most quickly were able to
carry out this labor for hours at a uniform rapidity
of 4 to 4-1/2 second for those 9 movements. But
the time-measurement showed that even these fastest
workers were relatively slow in the first 5 movements
which they made while the machine stood quiet, and
that they reached an astonishing quickness of movement
in the 4 last actions during which at the same time
the serrating hammer in bewildering rapidity was beating
on the plate with sharp loud cracks. The hammer
reinforced the energy of the young laborers to an
effectiveness which could never have been attained
by mere voluntary effort.
Often the simplicity or complication
of the stimulus may be decisive in importance, and
this also holds true where the most elementary reactions
are involved, for instance, the mere act of counting
which enters into many industrial functions.
Experiments carried on in my laboratory have shown
that the time needed to count a certain number of
units becomes longer as soon as the units themselves
become more complicated. Their inner manifoldness
exerts a retarding influence on the eye as it moves
from one figure to another. A certain psychical
inhibition arises; the mind is held back by the complexity
of the impression and cannot proceed quickly enough
to the next. Psychologically no less important
is the demand that the external technical conditions
so far as they influence consciousness, should remain
as far as possible the same, if the same psychical
effect is desired, because then only can a perfectly
firm connection between stimulus and movement be formed.
In technical life this demand is much sinned against.
A typical case is that of the signals for which the
engineer on the locomotive has to watch. In the
daytime the movable arms of the semaphore indicate
by their horizontal, oblique, or vertical position
whether the tracks are clear. At night-time, on
the other hand, the same information reaches him by
the different colors of the signal lanterns.
From a psychical point of view it is probable that
the safety of the service would be increased if an
unchangeable connection between signal and movement
were formed. It would be sufficient for that
purpose if the color signals at night were given up
and were replaced by horizontal, oblique, or vertical
lines of white light or rows of points. Successful
experiments of this kind have been carried on by psychologists
in the service of this railroad problem.
The interest in all these problems
of large concerns, in transportation and factory work
and complex industries, ought not to make us overlook
the fact that on principle the same problems can be
found in the simplest industrial establishment.
Even the housewife or the cook destroys economic values
if daily she has to spend useless minutes or hours
on account of arrangements in the household which are
badly adjusted to the psychological conditions.
She sacrifices her energy in vain and she wastes her
means where she herself is under the illusion of especial
economy. Scientific management would perhaps be
nowhere so wholesome as in kitchen and pantry, in laundry
and cellar, just because here the saving would be
multiplied millionfold and the final sum of energy
saved and of feeling values gained would be enormous,
even if it could not be calculated with the exactitude
with which the savings of a factory budget can be
proven. The profusion of small attractive devices
which automatically perform the economic household
labor and disburden the human workers must not hide
the fact that the chief activities are still little
adjusted to the psychophysical conditions. The
situation is similar to that of the masons, whose
function has also been performed for thousands of years,
and yet which did not find a real adaptation to the
psychical factors until a systematic time-measuring
study was introduced. A manufacturer who sells
an improved pan or mixing-spoon or broom expects success
if he brings to the market something the merits of
which are evident and make the housewife anticipate
a decrease of work or a simplification of work, but
the development of scientific management has shown
clearly that the most important improvements are just
those which are deduced from scientific researches,
without at first giving satisfaction to the laborers
themselves, until a new habit has been formed.
Perhaps the most frequent technical
activity of this simple kind is sewing by hand, which
is still entirely left to the traditions of common
sense, and yet which is evidently dependent upon the
interplay of many psychical factors which demand a
subtle adaptation to the psychical conditions.
To approach, at least, this field of human labor a
careful investigation of the psychophysics of sewing
has been started in my laboratory. The sewing
work is done, with the left hand supported, and the
right hand connected with a system of levers which
make a graphic record of every movement on the smoked
surface of a revolving drum. For instance, we
begin with simple over and over stitches, measuring
the time and the character of the right hand movements
for 50 stitches under a variety of technical conditions.
The first variation refers to the length of the thread.
The thread itself, fixed at the needle’s eye,
varied between 3 feet and 6 inches in length.
Other changes refer to the voluntary speed, to the
number of stitches, to fatigue, to external stimuli,
to attention, to methods of training, and so on, but
the chief interest remains centred on the psychical
factors. We are still too much at the beginning
already to foresee whether it will be possible to
draw from these psychophysical experiments helpful
conclusions. The four young women engaged in this
laboratory research will later extend it to the psychological
conditions of work with the various types of sewing-machines.