EXPLANATION OF OBSERVATIONS 145 



first began to take part in tests in which the procedure 

 was the one we characterized as " without knowledge " 

 and had to note their complete failure, he was thrown 

 into such confusion that the responses in the case of 

 procedure with knowledge were also incorrect. The 

 errors there were always + i, (whereas those in the case 

 of procedure with knowledge, which were due to quite 

 different causes, were very great and inconstant.) The 

 number of -)- i errors obtained on this occasion com- 

 prises one-fourth of all the plus errors which were evei- 

 obtained in the case of Mr. von Ost«n during the entire 

 course of these experiments. Finally, I would mention 

 two examples of my own. In the course of my very first 

 attempts with Hans I obtained, as I said on page 89, 

 three responses in a total of five which exceeded the cor- 

 rect result by i. This I would explain by the fact that 

 although I employed a high degree of concentration, I 

 nevertheless was somewhat skeptical. The result was a 

 certain deficiency in the degree of concentration. A 

 second example which I would cite is taken from the 

 period in which I had already discovered the cue to 

 Hans's reactions and goes to show that I was then still 

 able to eliminate the influence of this knowledge and to 

 work ingenuously. To the question, " How much is 9 

 less I ? " I, momentarily indisposed, received the answer 

 10, and then six times in succession the answer " 9 ", and 

 finally the correct response, " 8 ". 



Errors of another kind — the not infrequent offenses 

 against the very elements of counting and the funda- 

 mental arithmetical processes — were regarded in part 

 as intentional jokes and by an authority in pedagogy as 

 a " sign of independence and stubbornness which might 

 also be called humor ". Hans emphatically asserted that 



