Hugo Münsterberg.

Psychology and Industrial Efficiency online

. (page 9 of 16)
Online LibraryHugo MünsterbergPsychology and Industrial Efficiency → online text (page 9 of 16)
Font size
QR-code for this ebook


natural coördination 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.[26] 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.[27] 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[28]
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.[29] 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.[30] 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 coöperating, 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[31] 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.[32]

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.[33] 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.




XV

THE ECONOMY OF MOVEMENT


The study of the technical aspect of labor can nowhere be separated by
a sharp demarcation line from the study of the labor itself as a
function of the individual organism. Many problems, indeed, extend in
both directions. The student of industrial efficiency is, for
instance, constantly led to the question of fatigue. He may consider
this fatigue as a function of brain and muscle activity and discuss it
with reference to the psychophysical effort, but he is equally
interested in the question of how far the apparatus or the machine or
the accessory conditions of the work might be changed in order to
avoid fatigue. The accidents of the electric street railways were
regarded as partly related to fatigue. The problem was accordingly how
to shorten the working time of the motormen in the interest of the
public, but it was soon recognized that the difficulty might also be
approached from the mere technical side. Some companies introduced
seats which the motormen can use whenever they feel fatigue coming and
excellent results have followed this innovation. In our last
discussions the technical apparatus stood in the foreground. We may


1 2 3 4 5 6 7 9 11 12 13 14 15 16

Online LibraryHugo MünsterbergPsychology and Industrial Efficiency → online text (page 9 of 16)