PLAY AND INSTINCT. 71 



for future transmission. In short, where positive selec- 

 tion furthers the growth of intelligence, for instinct 

 there will be a certain degree of negative selection or 

 panmixia. (This, of course, applies only to instincts 

 for which conscious actions can be advantageously sub- 

 stituted.*) Indeed, it might even be said that the de- 

 generation of instinct is due to positive selection. We 

 have no intimation at what stage of evolution the ani- 

 mal world first achieves activity that depends on its 

 own intelligence or the capacity for individually ac- 

 quired association; but we may assume that at some 

 point in the progress of evolution the creature attained 

 sufficient intelligence to accomplish many things by 

 means of it better than by instinct. From this moment 

 on, extensive inheritance of brain mechanism would have 

 been positively prejudicial to the further development of 

 intelligence, and a positive selection may be assumed that 

 would directly favour less finished instincts in order to 

 produce in the nervous system a partiality for the now 

 more useful acquired functions, f 



* [Romanes thinks the existence of both sorts of function shows 

 the inheritance of acquired characters in the case of instincts 

 (Heredity and Utility, p. 74 f.) ; but Baldwin shows that in such 

 cases the instinctive performance has an additional utility, thus 

 supporting the position of the text (Science, New York, April 10, 

 1896).] 



f Wundt also points to this idea in the section on " Affects and 

 Impulses " in his Physiolog. Psychologie. Vol. ii, p. 512, of the 

 fourth edition runs thus : " The many-sidedness of a creature offers 

 a wide field for individual development, and at the same time the 

 determination by heredity is constantly diminished." Cf. the very 

 precise statement of this by Baldwin in Mental Development in 

 the Child, etc., chap, xvi, § 1 (German edition). [See Psychological 

 Review, iv, July, 1897, p. 399, and his preface to this work.] The 

 contrary supposition that imperfect instincts betoken early stages 

 in evolution is surely incorrect in many cases. 

 7 



