vn ASSIMILATION AND READJUSTMENT 125 



varying degree of numberless other birds and mammals in 

 instincts of various kinds. It is natural to look on the 

 aversion and terror manifested by a kitten when it first 

 sees a dog as based on an instinctive dread and horror of 

 dogs as dogs. But in fact what is congenital appears to 

 be a reaction to the dog's smell, 1 which can be inhibited, 

 moreover, by familiarity with friendly dogs. It is natural 

 to speak of a chick as instinctively dreading the cry of a 

 hawk, or as " knowing " its mother's warning cry or her 

 inviting cluck by instinct. But it appears truer to fact to 

 say that sounds of that quality affect the young bird, and 

 that the particular note to which it will respond by cower- 

 ing or coming forward will depend largely on the way in 

 which its hereditary tendencies have been modified by 

 experience. Similarly, one would say that a lamb instinc- 

 tively follows its mother. But it is truer to say that by 

 nature it has an inclination to follow any large animal, 

 and that experience teaches it to single out its mother as 

 the best animal to follow. Similarly, the young orang- 

 outang clings to its mother, but not because it is the 

 mother, but because it has a tendency to hang on by its 

 claws to something hairy a tendency of which Dr. Wallace 

 availed himself to make a dummy mother for an orphan of 

 that species. 



Summing up a mass of evidence upon this point, Mr. 

 Lloyd Morgan says, instincts 



..." are evoked by stimuli, the general type of which is 

 fairly definite, and may, in some cases, be in response to particular 

 objects. Of the latter possibility we have, however, but little 

 satisfactory evidence." 2 



And again, 



" acquired definiteness is built, through association, on the 

 foundation of congenital responses, which are modified, under 

 experience, to meet new circumstances." 3 



Thus the general function of experience, so far, is greatly 

 to increase the plasticity whereby the instinctive reactions 

 of an individual can be adjusted to his circumstances. It 

 may be said to make possible the rise of instincts adjusted 



1 Wesley Mills, pp. 176 and 177. 



2 Habit and Instinct, p. 99. 3 P. 100. 



