mand: "down" (below), and finally: "up"
(above). He often made just such incorrect movements of the head. In the
color-selecting tests the average of error was quite unpredictable. With
an equal number of tests, on one day, half would be successful, on
another, four fifths, on a third, one-tenth. Often Hans appeared to be
"indisposed" for days at a time. The color tests would often end in
expressions of rage on the part of Mr. von Osten and in consequence Hans
would become startled and would then storm about the courtyard so that
it was dangerous to try to approach him. Some may object that all this
was mere comedy and that possibly Mr. von Osten prevented some of the
tests from turning out successfully. But this objection is to be met by
the statement that very often failure would occur just when it was
particularly desirable to have the tests appear in a favorable light
before a large and enthusiastic assemblage of visitors. After such
failures he would be downcast on account of Hans's contrariness. It is
also significant that Mr. von Osten's percentage of error, corresponds
very closely with my percentage of error in the "non-voluntary" tests,
(page 84f.), whereas he never was able to obtain the errorless results
which I obtained in my "voluntary" experiments.

But we must be careful not to confuse non-voluntary movement and lack of
knowledge of the movement. And again we must distinguish between
knowledge of the grosser and the finer signals. Mr. von Osten was aware
of the grosser movements, and talked quite freely concerning them, but
in so doing, showed that he was quite unaware of their true function. He
undertook to show us what we already knew--that, when he remained
standing perfectly erect, he could elicit no sort of response from Hans.
Furthermore, that whenever he continued to bend forward, Hans would
always respond incorrectly and with very high numbers. He knew, also,
that Hans was distracted in his operations every time the questioner
resumed the erect posture while the tapping was in progress. This he
demonstrated to us on one occasion in the following manner. He said to
Hans: "You are to count to 7; I will stand erect at 5". He repeated the
test five times, and each time Hans stopped tapping when the master
raised his body. Several such tests resulted in the same way. Mr. von
Osten, however, believed this to be a caprice of the horse and at first
declared that he would yet be able to eliminate it, but l