is sentient from the first. Dividing the course of the observed behaviour into stages, we may say that the first stage is that in which the chick receives a visual stimulus accompanied by a sensation of sight. Upon this there rapidly follows the second stage, when the bird pecks, and its experience is widened by new data of consciousness derived from a group of motor sensations; and upon this, again, there follows the third stage, when sensations come in from the morsel of egg which the chick touched but just failed to seize. After a pause the chick strikes again. But we have not a mere repetition of the former sequence of stages. The visual stimulus at first fell upon the eye of a wholly inexperienced bird; now it falls upon the eye of one that has gained experience of pecking and tasting. What we may call the conscious situation has completely changed, at all events if we assume that the items of consciousness, including as essential the consciousness of behaviour, do not remain separate and isolated, but have coalesced into a group through association. And in this group the consciousness of behaving is perhaps the most important element in the situation, making it of practical value. What psychologists term the presentative visual stimulus, now calls up re-presentative elements, motor and gustatory; and these place the situation in a wholly new aspect. They give it what Dr. Stout terms "meaning." On the second or third attempt the chick seizes and swallows the morsel of egg. Its experience is yet further widened; and thereafter the situation has other new elements. Later it pecks at some nasty grub ; shakes its head, and wipes its bill on the ground. The conscious situation has for the future become more complex, and the behaviour is henceforth differentiated into that of acceptance and that of rejection, in each case determined by the acquired meaning in the coalescent conscious situation : the sight of a nice piece of egg being one situation, that of a nasty caterpillar another, each associated with its specific. behaviour-consciousness. We need not carry the illustration further on these lines: the essential feature is that experience grows by the coalescence of successive increments, and that

each increment modifies the situation which takes effect on the succeeding phases of behaviour, even if they succeed within the fraction of a second. That is what is meant by saying that present experience is for future guidance. The future need not be remote, but may be so immediate that in popular speech we may say that it is not future but present guidance which is rendered possible.

We may now turn for a moment to the criticism that there are numberless cases in which nothing of the nature of distinct memory is involved. We may now substitute for the word remembrance, which was used above, the more technical term re-presentation. Profiting by experience, regarded as a criterion of the presence of effective consciousness, involves re-presentative elements in the conscious situation which carry with them meaning. Let us for the moment assume an ultra-sceptical attitude with regard to any conscious accompaniment. The chick when it pecks, let us say, is an unconscious automaton. It seizes a piece of egg; this affords an unconscious stimulus, which sets agoing unconscious acts of swallowing; or it seizes a piece of meal soaked in quinine, which sets agoing unconscious acts of rejection and touches the hidden springs which make the automaton wipe its bill. So far we find no great difficulty. It is when we have to consider subsequent behaviour that a severe strain is felt on this method of interpretation. One can understand an automatic action repeated again and again as often as the stimulus is repeated. But the chick may shake its head and wipe its bill on the mere sight of the quinine-soaked meal, which, on the hypothesis of conscious experience, has already proved distasteful. So that if we

accept the unconscious automaton theory we must assume an organic association which closely simulates the conscious association to which our own experience testifies. But the associations which take part in the guidance of behaviour in the chick are so varied and delicate, so closely resemble those which in ourselves imply conscious guidance, that a sceptical attitude throws more strain upon our credulity than the acceptance of the current belief in conscious control.

We

shall therefore assume that evidence for such coalescent association is also evidence of the presence of effective consciousness.

It may still be said, however, that in selecting an example from so highly organized an animal as a bird, we are taking for granted that a complex case of controlled behaviour may fairly be accepted as a type of more simple cases. Unfortunately the only being with whose power of conscious control we have any first-hand acquaintance is possessed of a nervous system even more complex than that of the chick. Our psychological interpretations are inevitably anthropomorphic. All we can hope to do is to reduce our anthropomorphic conclusions to their simplest expression. The irreducible residuum seems to be that wherever an animal, no matter how lowly its station in the scale of life, profits by experience, and gives evidence of association, it must have some dim remembrance, or, let us now say, some re-presentation, of the results of previous behaviour which enters into and remodels the conscious situation; that through the re-presentative elements behaviour is somehow guided; and, further, that the centre of conscious control is different from the centre of response over which the control is exercised.

II. THE EARLY STAGES OF MENTAL DEVELOPMENT

We use the phrase "mental development" in its broadest acceptation as inclusive of, and applicable to, all phases of effective consciousness. We shall assume that throughout this development there is a concomitant development of nervecentres and of their organic connections. And we shall further assume that experience, as such, is not inherited.

The nature of the grounds on which the latter assumption is based must first be briefly indicated. It is commonly asserted that fear of man, the inveterate hunter and sportsman, is inherited by many animals, as is also that of other natural enemies. This is, however, questioned, or even denied, by many careful observers. Mr. W. H. Hudson has an excellent

chapter on "Fear in Birds" in his "Naturalist in La Plata,” and concludes that fear of particular enemies is, in nearly all cases, the result of experience individually acquired. I have found that pheasants, partridges, plovers, domestic chicks, and other young birds, hatched in an incubator, show no signs of fear in the presence of dog or cat, so long as the animal is not aggressive. It should be mentioned, however, that Miss M. Hunt asserts that chicks do show inherited fear of the cat. Dr. Thorndike's observations, on the other hand, support my own, which I have since repeated with the same results. Neither birds nor small mammals show any signs of fear of stealthily moving snakes.. My fox terrier smelt, nose to nose, a young lamb which was lying alone in a field. I was close at hand, and could detect no indication of alarm on the part of the lamb till the mother came running up in great excitement. Then the lamb ran off to her dam. Whenever opportunity has arisen, I have introduced young kittens to my fox terrier, and have never seen any sign of inherited fear. He was a great hunter of strange cats, but was trained to behave politely to all birds and beasts within the precincts of my study. It is true that he was on good terms, or at least terms of permissive neutrality, with the kittens' mother. And it may be said that this was inherited; but such an argument cannot apply in the case of pheasant or lamb.

Here, as throughout our study of animal behaviour in its conscious aspect, we have not only to conduct observations with due care, but to draw inferences with due caution. Douglas Spalding described how newly hatched turkeys showed signs of alarm at the cry of a hawk; and he inferred that, since this sound was quite new to their individual experience, the alarm was due to the inheritance of ancestral experience of hawks. But since young birds show signs of alarm at any sudden and unaccustomed sound—a sneeze, the noise of a toy horn, a loud violin note, and so forth--the safer inference seems to be that they may be frightened by strange * American Journal of Psychology, vol. ix., No. 1.

+ Psychological Review, vol. vi., No. 3.

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sounds of many kinds. But this does not imply the inheritance of experience, which is essentially a discriminating process. There is no sufficient evidence that a peculiar cry suggests the hawk, of which the progenitors have acquired bitter experience; nothing to justify the belief that the sound carries with it inherited meaning. And as with hearing, so with sight. Young birds may be frightened by many strange objects. I have seen a group of several species, filled with apparent alarm at a large white jug suddenly placed among them, at balls of paper tossed towards them, at a handkerchief dropped in their midst. It is, in fact, their inexperience which is often the condition of such fear. As Mr. Hudson says: * "A piece of newspaper carried accidentally by the wind is as great an object of terror to an inexperienced young bird as a buzzard sweeping down with death in its talons.'

Until recently it was commonly asserted that birds avoid gaudy but nauseous or harmful insects through the inheritance of experience gained by their ancestors through many generations. But here again the inference seems to have been incautiously drawn. Of the hundreds of young birds I have had under observation, not one has avoided the peculiarly distasteful cinnabar caterpillar, until it had gained for itself experience of its nauseous character. So too of wasps and bees. Only through experience are these avoided. It is true that chicks may shrink from them if they buzz or even walk rapidly towards them. But a large harmless fly will inspire just as much timidity. As the result of careful observations, Mr. Frank Finn † concludes "that each bird has to separately acquire its experience, and well remembers what it has learnt." And with this conclusion my own observations are entirely in accord.

Such is some of the observational evidence on which is based the provisional hypothesis that experience, as such, is not inherited. What, then, is inherited? Clearly the organic conditions under which experience can be acquired. Since a * "Naturalist in La Plata," p. 88.

† Journal Asiatic Society of Bengal, lxvii., part ii., 1897, p. 614.