hod had been procedure with knowledge, this
question had always been answered correctly, but when procedure was
without knowledge the responses were first 13, a tone which does not
exist for Hans, then 2, a tone which was not given in the clang to be
analyzed, and finally 3, which was not the discordant tone. Hans's
far-famed musical ability was an illusion.

Taking the results of all the tests into consideration, we find that in
the case of procedure with knowledge, 90 to 100% of the responses of the
various series were correct, whereas, in those series of procedure
without knowledge 10%, at most, of the responses were correct. Under the
conditions prevailing during these latter tests, even these 10% must be
regarded as due to chance. To be sure Mr. Grabow, a member of the school
board and an enthusiastic follower of Mr. von Osten (Zeitschrift fuer
Paedagogische Psychologie, Pathologie und Hygiene, Berlin, 1904, Jahrg.
6, Heft. 6, S. 470), mentions a large number of successful tests, which
were supposedly made in accordance with the method of procedure without
knowledge. A thorough analysis of his experiments was not possible,
because the conditions under which they were conducted were not
adequately specified. But I have no doubt that the successful responses
of the horse were due solely to the absence of precautionary measures.
I, too, could cite a number of seemingly correct responses which
demonstrably were due to the absence of adequate precautionary measures.
I therefore repeat: Hans can neither read, count nor make calculations.
He knows nothing of coins or cards, calendars or clocks, nor can he
respond, by tapping or otherwise, to a number spoken to him but a moment
before. Finally, he has not a trace of musical ability.

After all this experimentation it was evident that the horse was unable
to work alone, but was dependent upon certain stimuli from its
environment. The question therefore arose: does the horse get these
stimuli while the question is being put, or during his responses, i. e.,
during the process of tapping.

If Mr. von Osten's opinion was correct, then the process of questioning
played an important part in the success of the experiment. Of course, as
he said, it was not necessary to ask the question aloud; it was
sufficient--curiously enough--that it be inwardly spoken, thanks to the
horse's extraordinary auditory sensitivity. If, however, conditions were
made such that the auditory sense was