EXPLANATION OF OBSERVATIONS 143 



significant, that is, they might be interpreted as a mis- 

 _j22£ghg5^Q" "^ .thej[uestion. If, for instance, instead 

 of a sum only one of the quantities was given, or, if in- 

 stead of a product only one of the factors was given, it 

 might be interpreted that the horse simply wished to re- 

 peat the problem. Thus, Mr. von Osten in response to the 

 question : " How much is 3 times 5 ? ", twice in succession 

 received the answer, " 3 ", and upon my question, " How 

 much is 3 plus 4?" he answered, "3", and to "How 

 much is 2 times 6 ? " he tapped 6, and to " What is one- 

 fourth of 36?" 4. In part (certainly in the second and 

 third example cited) an individual quantity or factor 

 had been emphasized in the consciousness of the ques- 

 tioner (cf. page 105) and in part the reactions were due 

 to chance. Thus, when Mr. Hahn asked the question: 

 "What is one-half of 10?", he received the following 

 responses: 2 and 10, and then 17 and 3. To this class 

 belong also, the tests made by the Commission of Sep- 

 tember and reported in Supplement III. (See page 255). 

 Other errors, even though they may not have appeared 

 to be significant, might yet have been characterized as 

 mistakes du^ to speed ; as when, e. g., Hans made an error 

 of one unit — and sometimes, though less frequently, of 

 two units — too much or too little in his response. One 

 might be led to believe that Hans had not made an error 

 of calculation but merely of counting in the process of 

 giving his result, which always had to be done by the 

 cumbersome method of tapping. As a matter of fact, 

 the trouble lay in the wrong degree of concentration on 

 the part of the questioner: In errors of + i, tension was 

 too slight, in those of — i, it was too great (see pagegi). 

 This comes out clearly in a comparison of the two more 

 extensive series which I took in the case of Mr. Schil- 



