EXPLANATION OF OBSERVATIONS 151 



these two excuses. That they were without warrant is 

 shown by the fact that Hans, after appearing indisposed 

 or fatigued while working with one questioner, would 

 nevertheless react promptly and correctly a moment later 

 for some other experimenter, and furthermore, when 

 working with me, the number of his correct responses 

 would rise or fall with my own mental disposition. __—- ' 



Finally, I would here note a rather interesting obser- 

 vation for which I am indebted to Mr. Schillings and the 

 Count zu Castell. They had noticed, independently of 

 each other, that the horse would often fail to react 

 when for any length of time he was given problems deal- 

 ing _with abstract nu mber s^ even though they were of the 

 simplest kind; but that he would immediately improve 

 whenever the questions had to do withconcrete jjbject^,^.. 

 They believed that Hans found applied mathematics more 

 interesting, and that abstract problems, or those which 

 were altogether too elementary, bored him. The Count 

 zu Castell furthermore noticed that the responses tended 

 to be more correct as soon as he had the horse count 

 oij.eGts- which he, himself, (Castell) could see during the 

 test. Quite in "accord witK This is the statement to be 

 found in the report of the September-Commission, in 

 which we find this note in a discussion of the arithmetical 

 problems (not involving visible objects), which the gen- 

 tlemen already mentioned had given the horse. " The 

 horse responded with less and less attentiveness and ap- 

 peared to play with the questioner." Here again, that 

 was looked for in the animal which should have been 

 sought in the man. Mr. Schillings^ was capable of in- 

 tense, but not continued Concentration and it was he who 

 was bored, and not the horse^" And it was the Count zu 

 Castell and not the horse that found it necessary to in- 



