204 THE HORSE OF MR. VON OSTEN 



able to receive responses from the horse, and many of 

 them on the very first occasion ? The answer is not hard 

 to find. All of these persons came to the horse in very 

 much the same frame of mind — which found a similar 

 expression in all, in both posture and movements. And 

 it was these motor expressions of the questioner (aside 

 from the signs for " yes " and " no ", which I believe I 

 have adequately explained on page 98), that the horse 

 needed as stimuli for his activity. 



The next question that arises is: why did only a few 

 persons receive responses regularly from Hans, whereas 

 the greater number were favored only occasionally? 

 What was the selective principle involved? The answer 

 is, that the successful person had to belong to a certain 

 type, which embodied the following essential character- 

 istics. 



1. A certain measure of ability and tact in dealing with 

 the horse. As in the case of dealing with wild animals, 

 such as the lion, etc., Hans must not be made uneasy by 

 timidity in the questioner, but must be approached with 

 an air of quiet authority. 



2. The power of intense concentration, whether in ex- 

 pectation of a certain sensory impression (the final tap), 

 or in fixing attention upon some idea-content (" yes ", 

 " no ", etc.). It is only when expectancy and volition are 

 very forceful, that a sufficient release of tension can en- 

 sue. This release of tension is accompanied by a change 

 in innervation and results in a perceptible movement. 

 And it was only when the thought of " yes ", or " up ", 

 etc., was very vivid, that the nervous energy would spread 

 to the motor areas and thence to the efferent fibers, and 

 thus result in the head-movement of the questioner. 



