150 Habit and Instinct. 



ancestors. But if the cortical augmentation and inhibi- 

 tion are founded in heredity ; and if this augmentation 

 and inhibition form the basis upon which all acquisition 

 and all control are based ; what becomes of the distinction 

 between instinctive and acquired activities ? What, of 

 that between automatic and controlled behaviour ? 



Let us look again at the facts which we are endeavour- 

 ing to interpret. A chick sees for the first time in its 

 life a cinnabar caterpillar, instinctively pecks at it under 

 the influence of the visual stimulus ; seizes it, and under 

 the influence of the taste- stimulus instinctively shrinks. 

 So far we have instinct and automatism. Presently 

 we throw to it another similar caterpillar. Instinct 

 and automatism alone would lead to a repetition of 

 the previous series of events ; seeing, seizing, tasting, 

 shrinking. The oftener the experiment was performed 

 the more smoothly would the organic mechanism work, 

 the more definitely would the same sequence be repeated — 

 seeing, seizing, tasting, shrinking. Is this what we 

 actually observe ? Not at all. On the second occasion 

 the chick, under the influence of the previous experience, 

 acts differently. Though he sees, he does not seize, but 

 shrinks without seizing. We believe that there is a revival 

 in memory of the nasty taste. And in this we seem 

 justified, since we may observe that sometimes the chick 

 on such occasions wipes the bill on the ground as he does 

 on experiencing an unpleasant taste, though he have not 

 touched the larva. The chick, then, does not continue to 

 act merely from instinct and like an automaton. His 

 behaviour is modified in the light of previous experience. 

 What, then, has taken place in and through which this 

 modification, born of experience, is introduced? In 

 answering this question we disclose the essential feature of 

 the distinction we have all along been drawing — that 



