EXPLANATION OF OBSERVATIONS 201 



of perfect health, — which was curious enough when we 

 remember his rather unnatural mode of life. 



Hans's stubbornness was,.a myth. He was suspected of 

 it whenever the sameerror occurred a number of times 

 in succession, i. e., when the questioner did not properly 

 regulate his attention (page 146) or when he was being 

 controlled by " perseverative tendency ", mentioned on 

 page 149. Mr. Schillings, who has provided me with 

 material here as elsewhere, relates the following episode 

 which occurred on one such occasion. To one and the 

 same question put alternately by Mr. von Osten and Mr. 

 Schillings, Hans responded correctly, with two taps, to 

 the former, and just as persistently incorrectly, with three 

 taps, to the latter. After Mr. Schillings had sufiEered this 

 to occur three times he accosted the horse peremptorily : 

 " And now are you going to answer correctly ? ". Here- 

 upon Hans promptly shook his head, to the great merri- 

 ment of all those present. (Mr. Schillings had, with no 

 accounted reason, expected a "no".) Hans was called 

 willful whenever the same question was successively an- 

 swered by different responses, as frequently happened 

 with the increasing tension that characterized the high 

 numbers (page 145). He was also regarded as stubborn 

 when no reply at all was forthcoming, as in the tests with 

 the blinders;___ 



Hans's supposed distrust of the questioner, when the 

 latter did not know the answer to the problem, is noth- 

 ing but a poor attempt to account for the failure of those 

 tests. Hans's distrust of the correctness of his own re- 

 sponses was supposed to be evident from his tendency to 

 begin to tap once more if, after the completion of a task, 

 the questioner did not immediately give expression to 



