January 6, 192 1] 



NATURE 



591 



the metaphor, the territory is the scene of the 

 ■drama between arrival and departure ; that the 

 territory is secured and defended and the out- 

 burst of song in evidence before the females 

 arrive; and that the size of the territory is such 

 as to meet the requirements of the future. He 

 holds, then, that the territory, if not the pivot in 

 which the cycle of behaviour is centred, is the hook 

 of biological utility on which it is hung. 



Now, with regard to any routine of behaviour 

 or phase therein, four questions arise: (i) In re- 

 spect of the behaviour itself, is it unlearnt, or is 

 it acquired in the course of individual experience ? 

 (2) Under what conditions of external stimulation 

 does it come? (3) What is the good of it— its bio- 

 logical value? and (4) On what, in the constitu- 

 tion of the bird, does it depend? To the first 

 three questions observational evidence affords the 

 data for a reply. The answer to the last is in 

 large measure a matter of inference. 



As to the first, Mr. Howard is quite clear that, 

 on the evidence, much of the behaviour involved 

 in territorial routine is in form unlearnt. In so far 

 a.s it is unlearnt, it is instinctive. This does not 

 mean that the constituent details, as the matter 

 incorporated in the behaviour as a whole, are 

 purely instinctive. They are obviously in large 

 measure learnt. Skill in their performance has 

 been acquired. It means that the male bird in his 

 first year occupies and protects the territory, and 

 acts therein in specific ways, without having learnt 

 l)y previous experience this \orm of behaviour- 

 routine as a whole. Secondly, the external 

 stimulation is, in Mr. Howard's opinion, 

 afforded by the territorial situation, and not, 

 in the early stage, by the presence of a 

 female. To drive away an intruder involves, 

 of course, the stimulus of his presence; it 

 is, however, within the territory that the occu- 

 pant attacks him ; elsewhere, beyond its confines, 

 the behaviour is no longer the .same. The terri- 

 tory is, therefore, a feature of the situation that 

 counts. Thirdly, it is clear enough, on the evi- 

 dence, that the procedure has biological value. 

 But — and this is of prime importance — Mr. 

 Howard does not regard the prospective value of 

 instinctive behaviour as implying the presence in 

 mind of an end for the sake of which the bird acts. 

 The biological value of securing a territory is the 

 mating which follows in due course. We cx|>ect 

 this outcome l)ccausc we have knowledge of rou- 

 tine based on observation. But if the male in his 

 first year has never mated, he cannot, on the 

 basis of individually won experience, foresee 

 this mating and what follows thereon. It is 

 NO. 26; I. VOL. 106] 



not for him an end to be attained by his 

 behaviour. . This is imp>ortant — nay, essential 

 — to the interpretation offered. For if there be 

 inherited knowledge, the whole matter is easily 

 explained as due- to ancestral experience trans- 

 mitted through "memory" to the bird that be- 

 haves under its guidance. 



VVe come, then, to the fourth question : On 

 what, in the constitution of the bird, does the be- 

 haviour depend? Mr. Howard refers to physio- 

 logical changes in the organism which are cor- 

 related with tendencies to act in just that way 

 which is open to observation in the unlearnt be- 

 haviour. This is what we speak of in a broad and 

 general way as the nature of the bird. But this 

 nature, and the .correlated psychical nature, is dif- 

 ferent on different occasions. It is also at- 

 tuned to the circumstances at the time, and 

 gives to the behaviour much of its biological value. 

 Such an attunement of the nature Mr. Howard 

 calls a disposition. It is a state of physiological 

 and psychical preparedness to act appropriately 

 when the requisite stimulation is afforded. At 

 the moment of action it is focussed as impulse. 

 Thus at least may be interpreted many of Mr. 

 Howard's statements, though in others there 

 seems to be little difference between disposition 

 and impulse. He often sjjcaks of the disposition 

 or the impulse as being "rendered susceptible to 

 stimulation." For example, the territorial situa- 

 tion renders the impulse' to drive away intruders 

 susceptible. Some might prefer to speak of 

 the susceptibility of the bird when it is in 

 such a state as to respond to these or 

 those external conditions. We thus avoid the 

 risk of hypostatising a disposition or "an 

 instinct." The essential point, however, is that 

 the disposition that is inferred from the perform- 

 ance of unlearnt acts has factors which arc con- 

 genital, and do not depend on individually won 

 experience. 



Brief illustration may here be given of changes 

 of disposition. During the winter, before the 

 mating season, lapwings live together in fliK-ks. 

 The males are seemingly on the most friendly 

 terms with each other. Just such minor squabbles 

 occur as may give .some savour to the life of 

 enjoyment. The females are, for the males, just 

 other birds in the flock, and are not viewed, so 

 to speak, in the light of a disposition to mate. 

 Then in due season come the changes which con- 

 stitute ad hoc physiological and psychical pre- 

 paredness. Now one male and now another 

 leaves the flock and occupies a territory in the 

 fields; and. once there, he is intolerant of other 



