170 THE STUDY OF ANIMAL LIFE CHAP. 



as closely comparable to a chain of reflex actions, depend- 

 ing on inborn structural predispositions of the nervous 

 system, requiring no " mental ' hand on the reins but 

 merely the succession of stimuli. But many pieces of 

 instinctive behaviour have a suggestion of being " suf- 

 fused with awareness ' and of having behind them a 

 definite endeavour, (b) Others regard instinctive be- 

 haviour as quite inseparable from intelligence. But while 

 it is admitted that a blending of the two is common, a 

 study of both the achievements and the limitations of 

 instincts docs not seem to us to favour the view that 

 instinct is a sort of low-grade intelligence, (c) According 

 to others, instinct and intelligence are two radically 

 different, though often co-operative, kinds of knowing, 

 which have evolved along divergent lines. 



It is probable that there are two distinct kinds of in- 

 stinctive behaviour, that of ants, bees, wasps, and the 

 like, on the one hand, that of birds and the like, on the 

 other hand, for in the latter the inborn capacities are 

 modified by experience from the earliest days onwards. 

 There seems indeed to be a sharp contrast between (in 

 Sir Ray Lankester's phrase) the big-brain type, which 

 reaches its finest development in birds and mammals, and 

 the little-brain type, the climax of which is in ants, bees, 

 and wasps. The big-brain type is relatively poor in en- 

 grained capacities of instinctive behaviour, but is em- 

 inently educable. Thus the chick reared in the laboratory 

 does not know what water is, even when it is standing 

 in it and thirsty, it does not know what its unseen mother's 

 cluck means, and it will stuff its crop once or twice with 

 worms of red worsted. But it learns to find its way 

 about with prodigious rapidity and profits readily by 

 experience. The little-brain type, on the other hand, is 

 rich in engrained capacities of instinctive behaviour, but 

 is relatively non-educable. If a bell- jar be placed over 

 the nest of a ground-wasp, from the door of which the 

 inmates are wont to fly off, they are unable to force a 

 way out through the grass pressed down by the edge 

 of the glass. Yet the physical difficulty is not great, for 

 those outside can force a way in. When they enter. 



