150 THE HORSE OF MR. VON OSTEN 



It has been termed " perseverative tendency." (Persever- 

 ationstendenz ").^^ 



While the errors thus far discussed appeared sporadi- 

 cally in long series of correct responses, there still might 

 be observed at times a massing of errors, usually at the 

 beginning of a day of experimentation or at the begin- 

 ning of a new series. We were regularly told that Hans 

 always had to have time to adjust himself to new cir- 

 cumstances. The records often showed comments such 

 as these : " After a number of practice tests the horse 

 appears particularly well disposed ", or " Hans, at first 

 inattentive, does not respond. Suddenly he gets the hang 

 of things ". Different questioners who worked with the 

 horse required different lengths of time to obtain proper 

 responses. Some needed a quarter of an hour, others 

 scarcely half a minute. I, myself, found that in the 

 degree in which I learned to control my attention, in that 

 degree did this phenomenon tend to disappear, but would 

 reappear the moment I became indisposed. From this 

 we see that, instead of attributing all sorts of mental 

 characteristics, such as stubbornness, etc., to the horse, 

 we should lay them to the account of the questioner. As 

 a matter of fact we find that this " getting into the sweep 

 of things ", i. e. the overcoming of psycho-physical 

 inertia, has, long been known in the case of man and has 

 been experimentally determined and called " Anregung " 

 (excitation) by the psychiatrist, Kraepelin,^^ and his 

 pupil, Amberg.=' A massing of errors toward the end 

 of a long series occurred only when the questioner was 

 fatigued. There was nothing which had to be interpreted 

 as fatigue or as indisposition on the part of the horse, 

 (except in the few cases of very large numbers, of. 

 page 67). To be sure, Mr. von Osten always offered 



