EXPLANATION OF OBSERVATIONS 185 



probably answer : " As soon as my master stoops forward, 

 I begin to tap ; as soon as he moves, I stop. The thing 

 which induces me to act thus is the carrot which is given 

 me ; what it is that induces my master to make his move- 

 ments, I do not know." — It is therefore erroneous to 

 believe that animals require the power of abstract think- 

 ing in order to utilize the signs which are consciously 

 or unconsciously given them, as is argued by Goldbeck °' 

 when he says with reference to the training for visual 

 signs, which we have already mentioned before : 

 " There the dog has consciously interpreted the visual 

 impression in terms of the conclusion that he is expected 

 to bring forth the leaf indicated." Nor was there any 

 justification for the critic who thought he could put the 

 essence of the report of December, given in Supplement 

 IV, into the following words: " He (Hans) showed that 

 he has the power of attention, can draw logical conclu- 

 sions, and can communicate the result of his thinking, — 

 and all this independently." Yet none of this had been 

 asserted. The whole thing may be explained satisfactorily 

 by means of a process of simple association established 

 between the signs observed in the master and certain re- 

 actions on the part of the horse. The fact that the move- 

 ments made were so exquisitely minute does not change 

 the matter in the least. Such signs call for a high degree 

 of sensory keenness and great concentration of attention, 

 but by no means an " extremely high intelligence." 



Let us turn now from the consideration of visual per- 

 ception to th at of auditory perceptio n in the horse. We 

 saw that the "Tact that Hans was able to respond to com- 

 mands which were only inwardly enunciated, that is, 

 commands which were merely thought of but not spoken, 

 was not proof of great acuity of hearing, but rather that 



