.7..................6
10..................2.3.4.5.6.7.8.9............8..................8

PROBLEM 3. Alternate left and right ends

Doors No. of No. of
Settings open doors open right door
1..................5.6........................2..................5
2..................5.6........................2..................6
3..................4.5.6.7.8.9................6..................4
4..................4.5.6.7.8.9................6..................9
5..................1.2.3.4.5..................5..................1
6..................1.2.3.4.5..................5..................5
7..................2.3.4.5.6.7................6..................2
8..................2.3.4.5.6.7................6..................7
9..................3.4.5.6.7.8................6..................3
10..................3.4.5.6.7.8................6..................8

PROBLEM 4. Middle

Doors No. of No. of
Settings open doors open right door
1..................4.5.6.7.8..................5..................6
2..................1.2.3......................3..................2
3..................1.2.3.4.5.6.7.8.9..........9..................5
4..................2.3.4.5.6..................5..................4
5..................6.7.8......................3..................7
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 twent