78 MIND IN EVOLUTION CHAP. 



man likes to adhere to his particular way of doing a thing, 

 even though a better way be shown him. In proportion 

 as they exhibit this fixed and unadaptable uniformity of 

 response, instincts approach the compound reflex limit and 

 deserve to be called relatively mechanical. 



5. Instincts recede from this type in proportion as the 

 persistent internal disposition 1 influences the response. We 

 may illustrate the influence of such a condition from human 

 actions, where not heredity but an acquired habit is the 

 basis of co-ordination. As I walk down the street, I avoid 

 obstacles without thinking about them. The sjghtpf each 

 passer by, of the lamp post or an approaching cab dis- 

 charges suitable movemen^of jny.Jegs without unless the 

 danger is sudden or unusual distracting my thoughts from 

 the conversation which 1 am carrying on. The process is 

 reflex. If, instead of walking, I am bicycling, I avoid the 

 perils of 'bus or cab no less " instinctively," that is, auto- 

 matically. But here quite a different set of muscles are 

 called into play. I steer not by my feet but by my hands 

 and the swinging of my body. If a cart suddenly stops in 

 front of me, I grasp the brake. If I were briskly walk- 

 ing, I should pull up quite differently, with one foot out, 

 and knee bent but tense. In a word, the reflexes excited 

 by the same objects or circumstances differ according to 

 the pursuit in which I am for the time engaged. While 

 that pursuit continues the reflexes are set to play a 

 particular tune as each is touched. In this instance, the 

 setting is fixed by habit, but the effect is the same where 

 it is inherited. But it is not only reflexes that are so 

 determined but sensori-motor actions as well. The 

 clutching of the bicycle brake in the presence of an 

 obstacle may be mechanical, but if a child runs out into 

 the road, the cyclist executes a swift but graceful curve 

 and avoids it. The act may be unreflective but it needs 

 that element of judgment, of grasping several distinct 

 sensory data in relation which distinguishes the sensori- 

 motor from the reflex act. Now the sensori-motor act 



1 The German Stimmung used by Preyer (I. p. 197) in this connection 

 expresses my meaning better. Mr Lloyd Morgan calls the internal factor 

 a craving (Animal Behaviour, p. 102). 



