40 THE HORSE OF MR. VON OSTEN 



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 

 fiir Padagogische Psychologic, Pathologic 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 meas- 

 ures. I, too, could cite a number of seemingly correct 

 responses which demonstrably were due to the absence 

 of adequate precautionary measures. I therefore repeat :;j 

 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^ 



