262 THE HORSE OF MR. VON OSTEN 



working with the horse for a short time, regularly re- 

 ceived correct answers, without their being in any way 

 conscious of having given any kind of signal. 



So far as I can see, the following explanation is the 

 only one that will comport with these facts. The horse 

 must have learned, in the course of the long period of 

 problem-solving, to attend ever more closely, while 

 tapping, to the slight changes in bodily posture with 

 which the master unconsciously accompanied the steps 

 in his own thought-processes, and to use these as closing 

 signals. The motive for this direction and straining of 

 attention was the regular reward in the form of carrots 

 and bread, which attended it. This unexpected kind of 

 independent activity and the certainty and precision of 

 the perception of minimal movements thus attained, are 

 astounding in the highest degree. 



The movements which call forth the horse's reaction, 

 are so extremely slight in the case of Mr. von Osten, that 

 it is easily comprehensible how it was possible that they 

 should escape the notice even of practised observers. 

 Mr. Pfungst, however, whose previous laboratory ex- 

 perience had made him keen in the perception of visual 

 stimuli of slightest duration and extent, succeeded in 

 recognizing in Mr. von Osten the different kinds of 

 movements which were the basis of the various accom- 

 plishments of the horse. Furthermore, he succeeded in 

 controlling his own movements, (of which he had 

 hitherto been unconscious), in the presence of the horse, 

 and finally became so proficient that he could replace 

 these unintentional movements by intentional oneS; He 

 can now call forth at will all the various reactions 

 of the horse by - making the proper kind of . voluntary 

 movements, without asking the relevant question or 



