78 THE HORSE OF MR. VON OSTEN 



of the investigation. Once, when intending to ask the 

 horse to step backward to the right, I inadvertently said 

 " Step backward to the left ! ", whereupon he stepped 

 backward to the right. In spite of my verbal error, I had 

 involuntarily given him the proper directives. 



Finally we may note that Mr. von Osten had occa- 

 sionally asked the horse to jump or to rear. The com- 

 mand in this case was : " Jump ", or the question was : 

 " What do the horses do in the circus ? ". Since these 

 tests were just as effective when the command was given 

 silently, it was an indication that these, too, depended 

 upon visual stimuli. What was necessary to cause the 

 horse to step backward and then jump forward was to 

 step backward oneself, or make a slight movement of the 

 hand in that direction. If one wished to make him rear, 

 it might be effected by throwing the arm or head slightly 

 upward. 



///. Problems, which Hans solved by approaching the 

 objects to be designated. 



The method pursued in these tests was the following: 

 From five to eight pieces of colored cloth J^X/4 meters in 

 size were arranged in changing series upon the ground, 

 the interval between them being equal to the width of 

 one piece, or else they were hung upon a string a man's 

 height above the ground. This method was also employed 

 when placards of like size with written symbols were 

 used. The horse stood ten paces away and opposite the 

 middle of the series, while Mr. von Osten stood at his 

 right. Hans was asked to go and point out the cloth of 

 a certain color or the placard with a certain word upon it. 

 If the cloth lay upon the ground, Hans picked it up with 



