46 THE HORSE OF MR. VON OSTEN 



I would add that the horse— in so far as it was at all 

 possible to decide — never looked at the persons or the ob- 

 jects which he was to count, or at the words which he 

 was to read, yet he nevertheless gave the proper responses. 

 But he would always make the most strenuous efforts to 

 see the questioner. (See page 43). I would further- 

 more add that several experiments, in which Mr. von 

 Osten and the horse were separated from each other by 

 means of the canvas tent, failed completely, and that, on 

 the other hand, all tests were successful in which the ques- 

 tioner was present in the feed-room and the door between 

 this and the horse's stall was opened wide enough for him 

 to be seen by the horse. I would also mention that to- 

 ward evening the responses became less and less accurate. 

 The conclusion that visual stimuli were here operative 

 cannot be gainsaid. 



It was possible, to be sure, that other senses might also 

 be involved, but it was certain that auditory sensations 

 did not enter it. This is shown by the fact that one might 

 remain just as silent while the horse was tapping his 

 answer as during the putting of the question and yet 

 obtain a correct response. Hans, furthermore, could 

 scarcely be distracted by auditory stimulations. If either 

 the experimenter or anyone else present sought, at a given 

 moment, to interrupt him by such calls as " Hah ", 

 " Wrong ", etc., while he was going through the process 

 of tapping, they very seldom succeeded in their attempt. 

 Even though such interruption did succeed in seven out 

 of the twenty-one cases in which it was tried, the assump- 

 tion is well grounded that the success was due entirely 

 or almost entirely to minimal movements involuntarily 

 executed by those attempting the interruption. It is to 

 such minimal movements that the horse, as we shall 



