64a LIFE : OUTLINES OF GENERAL BIOLOGY 



and so on. But one must not take every case at its face value. 

 Training by man often results in an appearance of intelligence 

 which is not there. A clever device may be the outcome of random 

 trying and of ehminating useless movements without even picture- 

 logic. An animal, hke a man, may take intelligent advantage of 

 what is fortuitously discovered, as is probably the case when the 

 Greek eagle lets the Greek tortoise fall from a height so that the 

 carapace is broken. In certain ways the highest intelligence among 

 animals is exhibited by those that become man's responsible part- 

 ners, like shepherd dogs, horses, and elephants; but allowance ha.^ 

 to be made for direct training. It must be granted that there may 

 be profiting by experience below the level of intelligence; thus even 

 headless earthworms, and naturally ganghonless starfishes, can 

 learn. 



11. A large part of animal behaviour is instinctive, the outcome 

 of an inborn, ready-made power of doing apparently clever things. 

 It does not require to be learned, though it may be perfected b} 

 practice; it is shared almost equally by all members of the species 

 of the same sex: it has relerence to particular conditions of vital 

 importance or of frequent recurrence. Physiologically regarded, 

 instinctive behaviour is like a chain of reflexes ; but in some cases, at 

 least, it seems necessary to suppose that it is suffused with an aware- 

 ness that rises above mere sensitiveness to stimuli, and backed by 

 an endeavour that is more than generaUsed vital impulse. Instinct 

 is seen at its highest and purest in ants and bees ; it is subtly mingled 

 with intelligence in birds; it wanes before intelligence in the higher 

 mammals. 



12. It is a common error to say that man shows intelligence, 

 while animals show instinct. Man shows some instinctive behaviour, 

 as well as much inteUigent behaviour, and an occasional flavour of 

 rational conduct; animals often show both instinctive and intelhgent 

 behaviour, but some show little more than reflex actions. Man has 

 few clear-cut instincts; that term is often applied too loosely to 

 inborn predispositions and urges, or to the general promptings of 

 the Primary Unconscious. 



13. It is a mistake to regard instinct as a low form of intelligence, 

 or as the outcome of automatised intelligence. Instinctive behaviour 

 and intelligent behaviour arc on diverging lines of evolution. 



14. There seem to have been two main trends of advance in the 

 evolution of animal behaviour. On the one hand, there is the power 

 of fresh adjustment, of making little experiments or tentatives. 

 This is the line of individual initiative, and it has its cHmax in sheer 

 intelligence. On the other hand, there is the capacity for enregister- 

 ing profitable modes of behaviour, so that they become parts of the 

 inheritance, requiring no more than a Hberating stimulus for their 

 activation. In both cases there is inherited capacity; but among 



