Modification by Experience 307 



There are, as we have seen, various ways of learning by 

 experience slow ways that do not involve ideas, and 

 the rapid way that does. The great advantage of man 

 over most of the lower animals is not so much in the fact 

 as in the method of his learning. One of the most vital 

 meanings of the long period of helplessness and dependence 

 constituting human infancy lies in the fact that by reliev- 

 ing from the necessity of attending exclusively to external 

 objects, it renders possible attention to the sensations 

 resulting from movement; and thus, by supplying an 

 essential condition for the anticipated movements, it opens 

 the way for the control of movement through ideas. 



79. Some Alleged Instances of Remarkable Mental Powers 

 in Animals 



All of the experimental evidence which we have examined 

 indicates that even in the cleverest animals intellectual 

 ability falls far short of that demonstrated by rather dull 

 human beings. But a few years ago in Germany the 

 hypothesis was advanced that the minds of such animals 

 as horses and dogs are really quite on a par with those of 

 human beings; their apparent deficiencies being due to 

 the fact that we have never learned how to educate and 

 communicate with animals. In 1901 a Berlin gentleman, 

 Herr von Osten, began training a five-year old horse named 

 Hans to answer arithmetical questions by tapping with 

 his hoof on the ground. Taps with the right hoof meant 

 units, taps with the left hoof meant tens. Later, an al- 

 phabetic system was constructed on a numerical chart: 

 the letter a, for example, being found in the vertical column 

 numbered 3 and the horizontal column numbered 2, tap- 

 ping three times with the left hoof and twice with the right 



