ersonal
differences in these respects are extremely great, and are also
evident in the midst of small groups of persons who may have great
similarity in their education and training and in many other aspects
of their lives.

Among the most advanced students of my research laboratory, for
instance, all of whom have rather similar schooling and practically
the same training in experimental work, the product of mistakes and
seconds varied between 348 and 13,335. That smallest value occurred in
a case in which the time was 116 seconds and the sum of the mistakes
only 3, inasmuch as 3 cards of the most difficult group where the
predominating letter occurred only 15 times were put in the wrong
piles. The shortest time among my laboratory students was 58 seconds,
but with this individual the sum of the mistakes, calculated on the
basis of the valuation agreed upon, was 13. The largest figure
mentioned resulted in a case in which the student needed 381 seconds
and yet made mistakes the sum of which amounted to 35. It is
characteristic that the person with the smallest product felt a
distinct joy in the experiment, while the one with the largest passed
through painful minutes which put him to real organic discomfort. If
we arrange the men simply in the order of these products, of course we
cannot recognize the various groups, as those who are quick but make
mistakes and those who make few mistakes but act slowly may be
represented by the same products. The coincidence of the results with
the self-characterization is frequently quite surprising. Every one
has at some time come into unexpected, suddenly arising situations and
many have received in such moments a very vivid impression of their
own mental reaction. They know quite well that they could not come to
a decision quickly enough, or that they rushed hastily to a wrong
decision, or that in just such instants a feeling of repose and
security came over them and that with sure instinct they turned in
the direction which they would have chosen after mature thought. The
results of the experiments in sorting the cards confirmed this
self-observation in such frequent cases that it may indeed be hoped
that a more extended test of this method will prove its practical
usefulness. It is clear that the field is a wide one, as these
different types of mental dispositions must be of consequence not only
in the ship service, but also to a certain degree in the railroad
service and in ma