my disposal after the publication of the report of the
December-Commission. Some may say that we have had almost enough of a
good thing, but we must bear in mind that many of the tests which were
carried out,--such as those in which the method was that of "procedure
without knowledge", those in which the ear-muffs were used, those in
which distractions were introduced,--had previously been made by other
persons (see pages 41f, 45, 63), and with other results, than ours. A
more thorough test, therefore, would have been doubly desirable.

CHAPTER III

THE AUTHOR'S INTROSPECTIONS

In the preceding chapter we asked: What is it that determines the
horse's movements? Independent thinking, or external signs?--We found
that it was solely external signs, which we described as certain
postures and movements of the questioner. Beyond a doubt these necessary
signs were given involuntarily by all the persons involved and without
any knowledge on their part that they were giving any such signs. This
is to be seen from their statements, which cannot be cavilled at, as
well as from the fact that several of them even to-day still doubt the
correctness of the explanation which we are here offering. I myself for
some time made these involuntary movements quite unwittingly and even
after I had discovered the nature of these movements and had thus become
enabled to call forth at will all the various responses on the part of
the horse, I still succeeded in giving the signs in the earlier naive
involuntary manner. It is not easy, to be sure, to eliminate at once the
influence of knowledge and to focus attention with the greatest amount
of concentration on the number desired, rather than upon the movement
which leads to a successful reaction on the part of the horse. To some
this may appear impossible, but those who are accustomed to do work in
psychological experimentation, will not deny the possibility of such
exclusive concentration upon certain ideas.

If we now ask: "What occurred in the mind of the questioners, while they
were giving the signs?", the answer can be found only by way of the
process which in psychology is technically called "introspection", i. e.
observation of self. In the following we will give the most important
results of this process of self-observation, which took place in the
same period in which the observations recorded in the preceding chapter
were made.

My first experiments were made while the hors