6..................3.4.5.6.7.8.9..............7..................6
7..................7.8.9......................3..................8
8..................1.2.3.4.5.6.7..............7..................4
9..................2.3.4......................3..................3
10..................3.4.5.6.7..................5..................5



It was my aim so far as possible to present to a given subject each day
the ten settings under a given problem in order, without interruption.
If for any reason the series of observations had to be interrupted, it
was resumed at the same point subsequently. Occasionally it was found
desirable or necessary to present only five of the series of ten
settings in succession and then to interrupt observations for an
interval of a few minutes or even several hours. But as a rule it was
possible to present the series of ten settings. All things being
considered, it proved more satisfactory to give only ten trials a day to
each subject. Frequently twenty and rarely thirty trials were given on
the same day. In such cases the series of settings was simply repeated.
The only pause between trials was that necessary for resetting the
entrance doors and replenishing the food which served as a reward for
success.



III

RESULTS OF MULTIPLE-CHOICE EXPERIMENTS