282 The Animal Mind 



lack of development of the power to attend to movement 

 ideas. For the slight development of this power in most of 

 the lower animals there is at least one obvious reason. The 

 life of an animal in natural conditions demands that its 

 attention shall be constantly directed outward. It is en- 

 gaged in continual watchfulness for food and enemies. The 

 stimuli which come to it from external objects demand all 

 its mental energies ; the successful animal is the wide-awake, 

 alert animal. How can it, with every available avenue of 

 sense wide open to the external world, with every unit of 

 mental capital invested in watching and listening and smell- 

 ing, spare any mental energy to attend to the sensations from 

 its own movements ? It sees the prey, it makes an elaborate 

 series of movements in response to the sight ; but if it were to 

 attend for one instant to the sensations from the movements 

 themselves, there would be a relaxation of its watchfulness 

 of external things that might mean the escape of the prey. 

 But unless it attends to the sensations resulting from move- 

 ment, it will not reproduce them in idea. That which is 

 unattended to when originally experienced is ordinarily not 

 recalled. 



It would thus seem as though one condition which must be 

 fulfilled if movement ideas are to play an important part in a 

 creature's experience were that the animal should, for a time 

 at least, be set free from the pressure of the practical hand-to- 

 hand struggle for the means of existence, and thus enabled 

 in safety to attend to its own movement sensations. Animal 

 play, at first thought, offers an instance of such liberation 

 from practical necessities. But as Groos has shown, animal 

 play is not so unpractical as it looks (154). It is simply the 

 exercise of the same instincts upon which in other circum- 

 stances the animal's welfare depends. The attention is 

 absorbed in external objects quite as much in play as in 



