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 "a'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
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