with the
procedure and scoring we have used it is well located in year IX.

Wallin carries his assistance still further by saying, after the first
block has been placed, "Now, find the heaviest of the four," and after
the second has been placed, "Now, find the heaviest of the three," etc.
Finally, when the arrangement has been made, he tells the subject to try
them again to make sure the order is correct, allowing the subject to
make whatever changes he thinks necessary. This procedure robs the test
of its most valuable features. The experiment was not devised primarily
as a test of sensory discrimination, for it has long been recognized
that individuals who have developed as far as the 9- or 10-year level of
intelligence are ordinarily but little below normal in sensory capacity.

Psychologically, the test resembles that of comparing weights in V, 1.
Success depends, in the first place, upon the correct comprehension of
the task and the setting of a goal to be attained; secondly, upon the
choice of a suitable method for realizing the goal; and finally, upon
the ability to keep the end clearly in consciousness until all the steps
necessary for its attainment have been gone through. Elementary as are
the processes involved, they represent the prototype of all purposeful
behavior. The statesman, the lawyer, the teacher, the physician, the
carpenter, all in their own way and with their own materials, are
continually engaged in setting goals, choosing means, and inhibiting the
multitudinous appeals of irrelevant and distracting ideas.

In this experiment the subject may fail in any one of the three
requirements of the test or in all of them. (1) He may not comprehend
the instructions and so be unable to set the goal. (2) Though
understanding what is expected of him, he may adopt an absurd method of
carrying out the task. Or (3) he may lose sight of the end and begin to
play with the blocks, stacking them on top of one another, building
trains, tossing them about, etc. Sometimes the guiding idea is not
completely lost, but is weakened or rendered only partially operative.
In such a case the subject may compare some of the blocks carefully,
place others without trying them at all, but continue in his
half-rational, half-irrational procedure until all the blocks have been
arranged.

It is essential, therefore, to supplement the mere record of success or
failure by jotting down a brief but accurate description of the
perfor