THE AUTHOR'S INTROSPECTIONS 89 



If we now ask : " What occurred in the mind of the 

 questioners, while they were giving the signs ? ", the an- 

 swer can be found only by way of the process which in 

 psychology is technically called " introspection ", i. e. 

 observation of self. In the following we will give the 

 most important results of this process of self-observation, 

 which took place in the same period in which the observa- 

 tions recorded in the preceding chapter were made. 



My first experiments were made while the horse was 

 counting or solving arithmetical problems and were as 

 follows: Mr. Schillings, who was alone with me in the 

 horse's barn, asked me to think of several numbers, main- 

 taining that the horse would be able to indicate them cor- 

 rectly upon being asked. He stood to the right of the 

 horse, I stood erect and at the side of Mr. Schillings. 

 There was no one else present. Somewhat skeptical in 

 attitude, I concentrated my mind consecutively on five 

 small numbers. Hans tapped one of them incorrectly, 

 one correctly and three by one unit too many. At the 

 time I considered these attempts as unsuccessful and cred- 

 ited some curious chance with the answers which were 

 correct, or nearly so. This was a mistake, for often 

 during the following days, and in the absence of Mr. von 

 Osten, the horse would give correct answers. Others, of 

 course, would be incorrect, and usually the mistakes 

 would be by one unit, — so that I soon saw that even in 

 the horse's errors there lay some system. It will be seen 

 that Hans responded to me from the very beginning, un- 

 doubtedly because I had had the opportunity of watching 

 Mr von Osten and Mr. Schillings and had thus patterned 

 my behavior after theirs. I was not at first successful in 

 getting the horse to respond correctly in the case of large 

 numbers. For in order to get complete control over the 



