ose other simple mental functions could be
tested by routine methods of the psychological laboratory. This
consideration led me to propose ramified investigations concerning the
psychology of decision in its relation to the elementary mental
processes. These studies by students of the laboratory are not yet
completed. But I soon saw that they would be unfit for the solution of
my practical problem, as we recognized that these relations between
the complex act of decision and the elementary functions of the
individual seem to have different form with different types of
men.[12] If I was to approach the solution of the practical problem,
accordingly, I had to reproduce in an experimental form the act of
decision under complex conditions.

It seemed necessary to create a situation in which a number of
quantitatively measurable factors were combined without any one of
them forcing itself to consciousness as the most important. The
subject to be experimented on then has to decide as quickly as
possible which of the factors is the relatively strongest one. As
usual, here, too, I began with rather complicated material and only
slowly did I simplify the apparatus until it finally took an entirely
inconspicuous form. But this is surely the most desirable outcome for
testing methods which are to be applied to large numbers of persons.
Complicated instruments, for the handling of which special training is
needed, are never so useful for practical purposes as the simple
schemes which can be easily applied. The form of which I finally made
use is the following. I work with 24 cards of the size of
playing-cards. On the upper half of every one of these cards we have 4
rows of 12 capital letters, namely, A, E, O, and U in irregular
repetition. On 4 cards, one of these vowels appears 21 times and each
of the three others 9 times; on 8 cards, one appears 18 times and
every one of the three others 10 times; on 8 cards, one appears 15
times and each of the others 11 times; and finally, on 4 cards one
vowel appears 16 times, each of the three others 8 times, and besides
them 8 different consonants are mixed in. The person to be tested has
to distribute these 24 cards as quickly as possible in 4 piles, in
such a way that in the first pile are placed all cards in which the
letter A is most frequent, in the second those in which the letter E
predominates, and so on. As a matter of course the result must never
be secured by counting the letter