ix PSYCHO-PHYSICAL PHENOMENA 441 



\\V have seen that walking consists in a series of conipluA 

 movements which can be carried out automatically with case and 

 precision even when we do not attend to them ; but these move- 

 ments are the final result of a long and tedious series of voluntary 

 efforts which the child carries out in learning to stand on its feet 

 and to move by alternate steps so as not to tall, until it is able to 

 walk safely without the guidance of attention. To this it may lie 

 objected that the new-born infant is incapable of walking because 

 its complex nervous mechanisms are not yet fully developed. 

 The chick, in fact, can hop and peck at its food without preliminary 

 attempts, because the systems subserving these functions are 

 already well developed when it cracks the egg-shell. But turn to 

 the violin-player, in whom an hereditary transmission of the 

 artistic capacity is at most virtual, and not actual. Long and 

 arduous voluntary efforts, fatiguing attempts and graduated 

 exercises, must be faced by the would-be violinist before he 

 acquires the full mastery of the complicated neuro-muscular 

 mechanism necessary to the perfection of his art which is 

 attained only when he can find, without the slightest voluntary 

 effort, the multiple centrifugal paths for the impulses required in 

 the execution of the several musical sounds from which harmonic 

 combinations and melodic sequences result. 



This is a classical example of the gradual transformation of 

 conscious and voluntary into unconscious and mechanical acts by 

 practice and habit. We do not know what the organic and 

 functional changes due to habit that is, the frequent repetition 

 of the same act until we have acquired the faculty of executing 

 it perfectly consist in. To account for them in any way, we 

 must suppose that as the result of repeated exercise certain 

 definite neural paths are rendered more pervious, and conduction 

 through them is facilitated, while the spread of excitation to 

 other collateral paths is rendered more difficult. This hypothesis 

 explains why the habit that results from practice makes our 

 movements easier and simpler, less fatiguing and more perfect ; 

 why a less amount of attention is needed for their performance ; 

 why, finally, the acts that were originally conscious and voluntary 

 gradually become unconscious and mechanical. 



'" In action grown habitual," says William James, " what 

 instigates each new muscular contraction to take place in its 

 appointed order is not a thought or a perception, but the sensation 

 occasioned by the muscular contraction just finished. A strictly 

 voluntary act has to be guided by idea, perception, and volition 

 throughout the whole course. In an habitual action, mere 

 sensation is a sufficient guide, and the upper regions of brain 

 and mind are set sufficiently free." * 



It is just this simple sensation, capable of promoting complex 



1 Principles of Psychology, William James, 1890, i. p. 115. 



