EXPERIMENTS IN THE INTEREST OF TELEPHONE SERVICE
Our plan was to illustrate the possibility
of applying psychological experiments to the selection
of fit applicants also in cases in which not one characteristic
mental function stands out, but in which a large number
of relatively independent mental activities are in
play. I choose as an illustration of such cases
the work of the employees at the telephone switchboard.
A study of the psychological factors in this work
is strongly suggested by the practical interests of
the telephone companies, and may be looked on here
exclusively from this point of view. The user
of the telephone is little inclined to consider how
many actions have to be carried out in the central
office before the connection is made and finally broken
again. From the moment when the speaker takes
off the receiver to the cutting off of the connection,
fourteen separate psychophysical processes are necessary
in the typical case, and even then it is presupposed
that the telephone girl understood the exchange and
number correctly. It is a common experience of
the companies that these demands cannot be satisfactorily
fulfilled when a telephone girl has to handle more
than 225 calls in an hour. The official statistics
show that this figure is exceeded in not infrequent
cases, in extreme cases the number may even rise
beyond 300. Moreover, in short periods of reinforced
demands it may happen that for a few minutes even
the rapidity of 10 calls in a minute is reached.
Normally the burden is divided among the employees
in such a way that about 150 calls fall to each one
in an hour, and that this figure is passed considerably
only in one morning and one evening hour. A skillful
distribution of pauses and ample arrangements for
rest, usually together with very excellent hygienic
conditions, make it possible for the fit persons to
be able to carry on this work without over-fatigue
from 8 to 9 hours a day. On the other hand, it
is only natural that such rapid and yet subtle activity
under such high tension, where especially the quick
localization of the correct hole is a difficult and
yet indispensable part, can be carried out only by
a relatively small number of human nervous systems.
The inability to keep attention at such a high point
for a long while, or to perform such rapid movements,
or to retain the numbers correctly, does not lead
to fatal accidents like those in the case of the unfit
motormen, but it does lead to fatigue and finally to
a nervous breakdown of the employees and to confusion
in the service. The result is that the company
is continually obliged to dismiss a considerable proportion
of those who have entered the service and who have
spent some months in going through the training school
of the company. As one single company, the Bell
Telephone Company, employs 16,000 operators, the problem
is an expansive one, and it has bearing on the health
of the employees as well as on the patience of the
subscribers. But above all it refers to the economic
interests of the company, inasmuch as every girl who
satisfies the entrance conditions of hearing and sight,
of school education and general personal appearance,
receives some salary throughout the months of training
in the telephone school. Since during the first
half-year, in which the employee still works entirely
under supervision, more than a third of those who
had originally entered leave, partly on account of
unfitness, and inability, partly on account of over-fatigue
or similar reasons, the economic disadvantage to the
company is evidently a very great one. The candidates
are paid for months of mere training, and they themselves
waste their energy and time with practice in a kind
of labor which cannot be serviceable to them in any
other economic activity. Under these circumstances
it is not surprising that one city system approached
me with the question whether it would not interest
me from a scientific point of view to examine how far
the mental fitness of the employees could be determined
beforehand through experimental means.
After carefully observing the service
in the central office for a while, I came to the conviction
that it would not be appropriate here to reproduce
the activity at the switchboard in the experiment,
but that it would be more desirable to resolve that
whole function into its elements and to undertake
the experimental test of a whole series of elementary
mental dispositions. Every one of these mental
acts can then be examined according to well-known
laboratory methods without giving to the experiments
any direct relation to the characteristic telephone
operation as such. I carried on the first series
of experiments with about thirty young women who a
short time before had entered into the telephone training
school, where they are admitted only at the age between
seventeen and twenty-three years. I examined
them with reference to eight different psychophysical
functions. In saying this, I abstract from all
those measurements and tests which had somewhat anthropometric
character, such as the measurement of the length of
the fingers, the rapidity of breathing, the rapidity
of pulse, the acuity of vision and of hearing, the
distinctness of the pronunciation, and so on.
A part of the psychological tests were carried on
in individual examinations, but the greater part with
the whole class together.
These common tests referred to memory,
attention, intelligence, exactitude, and rapidity.
I may characterize the experiments in a few words.
The memory examination consisted of reading to the
whole class at first two numbers of 4 digits, then
two of 5 digits, then two of 6 digits, and so on up
to figures of 12 digits, and demanding that they be
written down as soon as a signal was given. The
experiments on attention, which in this case of the
telephone operators seemed to me especially significant,
made use of a method the principle of which has frequently
been applied in the experimental psychology of individual
differences and which I adjusted to our special needs.
The requirement is to cross out a particular letter
in a connected text. Every one of the thirty
women in the classroom received the same first page
of a newspaper of that morning. I emphasize that
it was a new paper, as the newness of the content
was to secure the desired distraction of the attention.
As soon as the signal was given, each one of the girls
had to cross out with a pencil every “a”
in the text for six minutes. After a certain
time, a bell signal was given and each then had to
begin a new column. In this way we could find
out, first, how many letters were correctly crossed
out in those six minutes, secondly, how many letters
were overlooked, and, thirdly, how the recognition
and the oversight were distributed in the various
parts of the text. In every one of these three
directions strong individual differences were indeed
noticeable. Some persons crossed out many, but
also overlooked many, others overlooked hardly any
of the “à’s,” but proceeded
very slowly so that the total number of the crossed-out
letters was small. Moreover, it was found that
some at first do poor work, but soon reach a point
at which their attention remains on a high level;
others begin with a relatively high achievement, but
after a short time their attention flags, and the
number of crossed-out letters becomes smaller or the
number of unnoticed, overlooked letters increases.
Fluctuations of attention, deficiencies, and strong
points can be discovered in much detail.
The third test which was tried with
the whole class referred to the intelligence of the
individuals. Discussion of the question how to
test intelligence in general would quickly lead us
into as yet unsettled controversies. It is a
chapter of the psychology of tests which, especially
in the service of pedagogy but to a certain degree
also in the service of medicine, has been more carefully
elaborated than any other. Often it has been
contested whether we have any right to speak of one
general central intelligence factor, and whether this
apparently unified activity ought not to be resolved
into a series of mere elementary processes. The
newer pedagogical investigations, however, speak in
favor of the view that besides all special processes,
or rather, above all of them, an ability must be recognized
which cannot be divided any further, and by which the
individual adjusts his knowledge, his experiences,
and his dispositions to the changing purposes of life.
The grading of the pupils in a class usually expresses
this differentiation of the intelligence; and while
the differences of industry or of mere memory and similar
secondary features may sometimes interfere, it remains
after all not difficult for an observant teacher to
grade the pupils of his class, whom he knows well,
according to their general intelligence. The psychological
experiments carried on in the schoolroom have demonstrated
that this ability can be tested by the measurement
of some very simple mental activities. The best
method would be the one which would allow the experimenter,
on the basis of a single experiment, to grade the
individuals in the same order in which they appear
in the record of the teacher. Among the various
proposed schemes for this purpose the figures suggest
that the most reliable one is the following method,
the results of which show the highest agreement between
the rank order based on the experiments and the rank
order of the teachers. The experiment consists
in reading to the pupils a long series of pairs of
words of which the two members of the pair always logically
belong together. Later, one word of each pair
will be read to them and they have to write down the
word which belonged with it in the pair. This
is not a simple experiment on memory. The tests
have shown that if instead of logically connected
words simply disconnected chance words are offered
and reproduced, no one can keep such a long series
of pairs in mind, while with the words which have
related meaning, the most intelligent pupils can master
the whole series. The very favorable results
which this method had yielded in the classroom made
me decide to try it in this case too. I chose
for an experiment 24 pairs of words from the sphere
of experience of the girls to be tested. Two
further class experiments belonged rather to the periphery
of psychology. The exactitude of space-perception
was measured by demanding that each divide first the
long and then the short edge of a folio sheet into
two equal halves by a pencil mark. And finally,
to measure the rapidity of movement, it was demanded
that every one make with a pencil on the paper zigzag
movements of a particular size during the ten seconds
from one signal to another.
After these class experiments I turned
to individual tests. First, every girl had to
sort a pack of 48 cards into 4 piles as quickly as
possible. The time was measured in fifths of a
second. The following experiment which referred
to the accuracy of movement impulses demanded that
every one try to reach with the point of a pencil 3
different points on the table in the rhythm of metronome
beats. On each of these three places a sheet
of paper was fixed with a fine cross in the middle.
The pencil should hit the crossing point, and the
marks on the paper indicated how far the movement had
fallen short of the goal. One of these movements
demanded the full extension of the arm and the other
two had to be made with half-bent arm. I introduced
this last test because the hitting of the right holes
in the switchboard of the telephone office is of great
importance. The last individual experiment was
an association test. I called six words like
“book,” “house,” “rain,”
and had them speak the first word which came to their
minds. The time was measured in fifths of a second
only, as subtler experiments, for which hundredths
of a second would have to be considered, were not
needed.
In studying the results so far as
the memory experiments were concerned, we found that
it would be useless to consider the figures with more
than 10 digits. We took the results only of those
with 8,9, and 10 digits. There were 54 possibilities
of mistakes. The smallest number of actual mistakes
was 2, the largest, 29. In the experiment on
attention made with the crossing-out of letters, we
found that the smallest number of correctly marked
letters was 107, the largest number in the six minutes,
272; the smallest number of overlooked letters was
2, the largest, 135; but this last case of abnormal
carelessness stood quite isolated. On the whole,
the number of overlooked letters fluctuated between
5 and 60. If both results, those of the crossed-out
and those of the overlooked letters, are brought into
relation, we find that the best results were a case
of 236 letters marked, with only 2 overlooked, and
one of 257 marked, with 4 overlooked. The very
interesting details as to the various types of attention
which we see in the distribution of mistakes over the
six minutes were not taken into our final table.
The word experiments by which we tested the intelligence
showed that no one was able to reproduce more than
22 of the 24 words. The smallest number of words
remembered was 7. The mistakes in the perception
of distances fluctuated between 1 and 14 millimeters;
the time for the sorting of the 48 cards, between,
35 and 58 seconds; the association-time for the 6
associated words taken together was between 9 and 21
seconds. The pointing experiments could not be
made use of in this first series, as it was found
that quite a number of participants were unable to
perform the act with the rapidity demanded.
Several ways were open to make mathematical
use of these results. I preferred the simplest
way. I calculated the grade of the girls for
each of these achievements. The same candidate
who stood in the 7th place in the memory experiment
was in the 15th place with reference to the number
of letters marked, in the 3rd place with reference
to the letters overlooked, in the 21st place with
reference to the number of word pairs which she had
grasped, in the 11th place with reference to the exactitude
of space-perception, in the 16th place with reference
to the association-time, and in the 6th place with
reference to the time of sorting. As soon as
we had all these independent grades, we calculated
the average and in this way ultimately gained a common
order of grading. It is evident that this kind
of calculation contains accidental factors, especially
as a consequence of the fact that we give equal value
to every one of these results. It might be better,
for instance, to attribute a higher value to the attention
experiment or to the intelligence experiment.
This could be done by multiplying the results of some
of these grades by 2 or by 3, which would bring the
high or low grade of a girl for a particular function
to stronger influence in the final result. But
in this first trial I contented myself with the simplest
uniform scheme in order to exclude all arbitrariness,
and therefore considered the mere average of all the
grades as the expression of the experimental result.
With this average rank list, we compared
the practical results of the telephone company after
three months had passed. These three months had
been sufficient to secure at least a certain discrimination
between the best, the average, and the unfit.
The result of this comparison was on the whole satisfactory.
First, the skeptical telephone company had mixed with
the class a number of women who had been in the service
for a long while and had even been selected as teachers
in the telephone school. I did not know, in figuring
out the results, which of the participants in the
experiments these particularly gifted outsiders were.
If the psychological experiments had brought the result
that these individuals who stood so high in the estimation
of the telephone company ranked low in the laboratory
experiment, it would have reflected strongly on the
reliability of the laboratory method. The results
showed, on the contrary, that these women who had
proved most able in practical service stood at the
top of our list. Correspondingly, those who stood
the lowest in our psychological rank list had in the
mean time been found unfit in practical service and
had either left the company of their own accord or
else had been eliminated. The agreement, to be
sure, was not a perfect one. One of the list
of women stood rather low in the psychological list,
while the office reported that so far she had done
fair work in the service, and two others to whom the
psychological laboratory gave a good testimonial were
considered by the telephone office as only fair.
But it is evident that certain disagreements
would have occurred even with a more ideal method,
as on the one side no final achievement in practical
service can be given after only three months, and because
on the other side a large number of secondary factors
may enter which entirely overshadow the mere question
of psychophysical fitness. Poor health, for instance,
may hinder even the most fit individual from doing
satisfactory work, and extreme industry and energetic
will may for a while lead even the unfit to fair achievement,
which, to be sure, is likely to be coupled with a
dangerous exhaustion. The slight disagreements
between the psychological results and the practical
valuation, therefore, do not in the least speak against
the significance of such a method. On the other
hand, I emphasize that this first series meant only
the beginning of the investigation, and it can hardly
be expected that at such a first approach the best
and most suitable methods would at once be hit upon.
A continuation of the work will surely lead to much
better combinations of test experiments and to better
adjusted schemes. But it would be most desirable
that such studies be undertaken at various places
according to various schemes in order to come nearer
to the solution of a problem which is economically
important to the whole public and to many thousands
of employees. As soon as methods are really perfected
it would seem not at all impossible that by a short
experiment of a few minutes thousands of applicants
might be saved long months of study and training which
are completely wasted. For us here the detailed
analysis of this particular case did not mean a suggestion
to use to-day in the telephone offices of the country
the special scheme which we applied, but it stood
only as a clear, simple illustration of a method by
which not the specific work itself is tested, but by
which the industrial work of the individual is resolved
into a long series of parallel functions each one
of which is tested independently. The experimental
aid which the laboratory has to supply in such cases
is not a newly invented device, such as we needed in
the case of the motormen, but simply the methods well
known as so-called mental tests.
The experiments with such tests by
which single mental functions are measured approximately
in short quick examinations, has been much discussed
in psychological circles. For a long while the
thorough scholars remained very reluctant to accept
such an apparently superficial scheme, when these
tests were proposed especially for the pedagogical
interests of the schoolroom. It was a time in
which the scientific efforts were completely devoted
to the general problems of the human mind and in which
individual differences were very little considered.
Moreover, the questions of applied psychology still
seemed so far distant that the true scholar instinctively
took his standards from the methods of purely theoretical
research. Seen from such a point of view, it
could not be denied that the tests were not sufficient
to give us a complete scientific analysis of the personality
in its subtler structure. The theorists knew too
well that if the reactions, or associations, or memories,
or tendencies of attention, or emotions of a subject
were measured really with that scientific thoroughness
which is the ideal of research, long months of experiments
would be needed, and little could be hoped for from
tests to be performed in half an hour. But this
somewhat haughty reserve which was quite justified
twenty years ago has become obsolete and would be
meaningless to-day. On the one side the methods
themselves have been multiplied; for each mental act
like memory, attention, and so on, dozens of well-studied
tests are at our disposal, which are adjusted to the
finest ramifications of the functions. On the
other side the interest in individual differences and
in applied psychology has steadily grown, and through
it an understanding for the real meaning of the tests
has been gained. Their value, indeed, lies exclusively
in their relation to the practical problems. Where
theoretical questions are to be answered and scientific
studies concerning the laws and variations of the
mind are to be undertaken, the long series of laboratory
experiments carried on with patience and devotion
are indispensable and can never be replaced by the
short-cut methods of the tests. But where practical
tasks of pedagogy or jurisprudence or medicine, or
especially of commerce and industry, are before us,
the method of tests ought to be sovereign. It
can be adapted to the special situations and can succeed
perfectly, if the task is to discover the outlines
of the mental individuality for particular practical
work.
The only real difficulty of the method
lies in the ease with which it can be used. A
device which presupposes complicated instruments deters
the layman and will be used only by those who are well
trained. Moreover, the amateur would not think
of constructing and adapting such apparatus himself.
But when nothing is necessary but to use words or
numbers or syllables or pictures, or, as in those experiments
which we just described, newspapers and so on, any
one feels justified in applying the scheme or in replacing
it by a new apparently better one according to his
caprice. The manifoldness of the proposed tests
for special functions, is therefore enormous to-day.
What is needed now is surely much more that order
be brought into this chaos of propositions, and that
definite norms and standards be secured for certain
chief examinations, than that the number of variations
simply be increased.
The chief danger, moreover, lies in
the fact that those who are not accustomed to psychological
laboratory research are easily misled. They fancy
that such an experiment can be carried out in a mere
mechanical way without careful study of all the conditions
and accompanying circumstances. Thereby a certain
crudeness of procedure may enter which is not at all
suggested by the test method itself. The psychological
layman too seldom recognizes how many other psychical
functions may play a rôle in the result of the experiment
beside the one which is interesting him at that moment.
The well-schooled laboratory worker almost automatically
gives consideration to all such secondary circumstances.
While his experiments may refer to the process of
memory, he will yet at the same time carefully consider
the particular situation as to the emotional setting
of the subject, as to his attention, as to his preceding
experience, as to his intelligence, as to his physiological
condition, and many other factors which may have indirect
influence even on the simplest memory test. Hence
the real performance of the experiments ought to be
undertaken only by those who are thoroughly familiar
and well trained in psychological research. And
they alone, moreover, can decide what particular form
such an experiment ought to take in a given practical
situation. It must be left to them, for instance,
to judge in which cases the mental function of economic
importance ought to be tested after being resolved
into its components and in which it ought to be examined
in its characteristic unity.