no MIND IN EVOLUTION CHAP. 



to the stimulus, and in this way we soon, or late, learn 

 to balance without perceptible oscillation or conscious 

 effort. The improvement is, doubtless, largely due to the 

 confirmation of more and inhibition of less successful 

 responses. But it would seem that something must also 

 be set down to the readier appreciation and more perfect 

 conduction of the excitement by the nerves their more 

 perfect control of the muscles. At any rate, this explana- 

 tion has to be taken into account wherever we have to deal 

 with an action which is the same in general character and 

 apparent purpose from the beginning, and merely improves 

 with practice in its execution. It probably explains the 

 slowly acquired mastery of its reflexes by a young child, 

 and the rapidly growing perfection of pecking by a newly 

 hatched chick. 1 And I should be inclined to apply it to 

 most of the many human accomplishments in which what 

 one is definitely taught bears but a small proportion to 

 what muscles, nerves, and nerve centres have to learn in 

 the way of execution. 



But there are other cases in which action is not merely 

 improved in execution, but profoundly modified in 

 character by experience. We may say that it is re- 

 directed. And in these cases we can point to the results 

 of the act as the operative cause. The burnt child that 

 dreads the fire does not grasp at the flame more efficiently, 

 but refrains from grasping at all. The direction or aim of 

 the action is reversed, and reversed, as we know, in con- 

 sequence of its result when tried. It is because the child 

 has modified its behaviour in consequence of a relation 

 experienced between act and consequent, that its conduct 

 has been taken as the type of experience acting as the 

 basis of rational conduct. The unit of reasoning is a 

 relation of datum and consequence, whether the act of 

 reasoning be merely to apply the knowledge of the relation 

 in a fresh case, or to use it as a brick in building up some 

 more complex mental structure. There are vast differ- 

 ences between the ways in which this relation is grasped 

 and used by minds of different order, but the relation 



1 See Lloyd Morgan, Habit and Instinct, p. 36. See also Preyer, I. 

 p. 236, and Thorndike, Psych. Review^ Vol. VI. pp. 284 et seq. 



