Animal Behaviour

by C. Lloyd Morgan

II.—The Biological Aspect

The biological aspect of behaviour—its relation to biological ends—has so often come under our consideration in the foregoing chapters that little need be added in this section: and that little may be most appropriately devoted, first to the question whether consciousness does influence behaviour; and secondly, this being accepted, to the importance of the rôle that is played by the development of conscious situations in securing, in the higher animals, the biological end of racial preservation.

That this end is secured without the aid of consciousness in the case of many organic species, in all those, for example, which we classify as plants, must not be taken as presumptive evidence that in other species, for instance in the multitudinous host of insects, the development of conscious situations is of no biological value. The fact that chlorophyll is not developed in any mammal does not show that the possession of this substance is of no service to the higher plants. It would not be worth while to give expression to this very obvious truth, were it not that critics of natural selection persistently argue that because one species gets on perfectly well without this or that particular character it can have played no part in securing the survival of another species. When I described, at a meeting of naturalists, how well young chicks could swim, such a critic drew me aside after the meeting, and expressed his surprise that this did not convince me that the webbed foot of the duck could not logically be attributed to natural selection. This is an extreme case, and one obviously taken on peculiarly weak grounds. But even Huxley urged that, because a frog, from which the cerebral hemispheres have been removed, performs many co-ordinated actions without conscious guidance, consciousness is, throughout nature, merely an accompaniment of certain molecular changes in the brain. “Such a frog,” he says,[197] “walks, hops, swims, and goes through his gymnastic performances quite as well without consciousness, and consequently without volition, as with it; and if a frog, in his natural state, possesses anything corresponding with what we call volition, there is no reason to think that it is anything but a concomitant of the molecular changes in the brain which form part of the series involved in the production of motion.

“The consciousness of brutes,” he continues, “would appear to be related to the mechanism of their body simply as a collateral product of its working, and to be as completely without any power of modifying that working as the steam-whistle which accompanies the work of a locomotive engine is without influence on its machinery. Their volition, if they have any, is an emotion indicative of physical changes, not a cause of such changes. It does not enter into the chain of causation of their actions at all.”

If the literal truth of this contention—the logical soundness of this conclusion—be admitted, it seems absurd to speak of the biological value of consciousness in behaviour or to discuss the importance of the rôle that is played by the development of conscious situations in securing the biological end of racial preservation.

Now, consciousness is regarded by an influential school of thinkers as a sort of deus ex machina, which, sitting enthroned, and crowned with a capital letter as Will, directs, like a being from another sphere, the doings of the body. It was against the doctrines of this school that Huxley took up arms. They do not concern us here. The will, or volition, as an underlying cause, stands outside the pale of scientific inquiry. It belongs to the wide realm of metaphysics; its plea must be heard in another court. In this part of his contention Huxley was, we believe, unquestionably right from the scientific standpoint. Neither will, nor impulse, nor instinct, nor consciousness itself, should be introduced into any scientific description or explanation of phenomena as a cause of their existence or being, for as such it does not enter into the sequence of events; it is that which metaphysics claims as their raison d’être—that which gives them being. Science in this matter should be frankly agnostic—neither affirming nor denying aught. This, of course, is not equivalent to saying that the agnostic position is the true end of human reason. That would only be so on the assumption that the problems of science are the only problems with which that reason can deal. To exclude metaphysics from science is not to exclude it from human thought. As a matter of fact such exclusion is neither possible nor reasonable. But to clearly distinguish the problems of science from those of metaphysics is absolutely necessary, if we are to prevent hopeless confusion of issues.

In contending, however, against the introduction of metaphysical doctrines into the region of scientific explanation, Huxley seems to have been carried too far by the force of his own attack. So long as he held to the position that every conscious state has, as its concomitant, a molecular change in the brain, he had all the forces of evolution on his side. But when he said that consciousness is merely the steam-whistle of life’s locomotive, or merely answers to the sound which the animal-bell gives out when it is struck, he takes up another position of far less strategical strength. For whereas the frog from which the physical centres of consciousness have been removed sits crouched and motionless, and “will starve sooner than feed itself, although food put into its mouth is swallowed;” the frog in which conscious situations can take form in unmutilated cerebral hemispheres behaves in a very different manner. It is nothing less than pure assumption to say that the consciousness, which is admitted to be present, has practically no effect whatever upon the behaviour. And we must ask any evolutionist who accepts this conclusion, how he accounts on evolutionary grounds for the existence of a useless adjunct to neural processes.

“It is,” says Huxley,[198] “experimentally demonstrable—any one who cares to run a pin into himself may perform a sufficient demonstration of the fact—that a mode of motion of the nervous system is the immediate antecedent of a state of consciousness. We have as much reason for regarding the mode of motion as the cause of the state of consciousness, as we have for regarding any event as the cause of another. How the one phenomenon causes the other we know as much, or as little, as in any other case of causation; but we have as much right to believe that the sensation is an effect of the molecular change, as we have to believe that motion is an effect of impact; and there is as much propriety in saying that the brain evolves sensation, as there is in saying that an iron rod, when hammered, evolves heat.” But if we speak of the related antecedent as the cause, it is not obvious why we should not describe the desire to demonstrate the supposed fact as the cause of running in the pin. We seem to have just as much reason for calling this antecedent state of consciousness the cause of certain movements and behaviour, as of calling a mode of motion in the brain the cause of a further state of consciousness. It is true that we have not the least idea how the desire can cause the act; but Huxley practically admits that we have no idea how molecular change can be the cause of consciousness. In the one case we are no worse off than we are in the other. Neither position is logically defensible; since each assumes that physical events and states of consciousness can constitute links in the same causal chain.

The philosophical hypothesis known as monism regards the molecular change, not as the antecedent of a conscious state, but as its concomitant. That which from a physical and physiological point of view is a complex molecular disturbance is, at the same time, from a psychological point of view, a state of consciousness. The two are different aspects of one natural occurrence. Why such an occurrence should have two so different aspects we have not the faintest idea; but here we are not one whit worse off than we were before. The hypothesis does, however, help us to get over our difficulty. An essential feature of Huxley’s contention is that the physical and physiological chain of causation is complete in itself, which may be granted; and further, that if consciousness does arise it is merely an adjunct without influence on the sequence of events—what is influential is the molecular disturbance, not the consciousness which accompanies it. But according to monism the state of consciousness actually is that very same something which the physiologist calls, in the language of physics, a molecular disturbance. And in saying that consciousness influences behaviour one who accepts this hypothesis is merely avoiding a cumbrous form of circumlocution. He puts it in this way instead of saying that the nerve-changes in the cerebral hemispheres, or elsewhere, which from a psychological point of view are a conscious situation, influence and determine the course of behaviour. But from this point of view it is absurd to say that the consciousness is merely an adjunct—absurd to say that were there no conscious situation the neural situation would remain unchanged. They are the very same thing from different points of view; and to say there is no influential conscious situation is simply equivalent to saying that there is not this determining neural situation.

However we explain the fact, there are few who hesitate to accept it for the purposes of scientific explanation. The conscious situation, having no doubt for the physiologist a neural aspect if he could only get at it as a whole, does practically determine the behaviour of the animal which has gained the requisite experience. If we accept the fact, we may pass on to its importance in securing the biological end of race preservation.

It is a commonplace of evolutionary doctrine that, other things being equal, those races will survive, in the constituent members of which intelligent behaviour enables them to deal most effectually with an environment of increasing complexity. And it is a matter of familiar observation that such behaviour is closely connected with delicacy and refinement of development in those senses which take the lead in cognitional process, and with rapidity and precision in the motor co-ordination through which prompt and skilful advantage is taken of the situation which has, through experience, acquired meaning.

But though the importance of intelligent adjustment to the circumstances of life is widely admitted as a general principle, it is perhaps through a study of animal behaviour that we are best able to realize its full range and extent. Biologists are so largely, and quite wisely, occupied in the study of morphological and physiological problems, which admit of a treatment more exact than the most ardent advocate of the investigation of behaviour, under natural or even under experimental conditions, can claim; they devote, again quite rightly, so large a share of attention to the variation and natural selection of adaptive structure in its adult condition and embryonic stages; the pendulum of opinion has, under the teaching of Professor Weismann, swung so far in the direction of the non-acceptance of the hereditary transmission of characters individually acquired through intelligent adjustment or otherwise; that the part played by consciousness in the evolution of the higher and more active animals is apt to pass unnoticed or unrecorded. It is well, therefore, to put in a reminder that a great number of animals would never reach the adult state in which they pass into the hands of the comparative anatomist save for the acquisition of experience, and the effective use of the consciousness to which they are heirs; that their survival is due, not only to their possession of certain structures and organs, but, every whit as much, to the practical use to which these possessions are put in the give and take of active life; and that many interesting problems which are keenly discussed by evolutionists in the light of natural selection presuppose conscious situations which are more or less tacitly taken for granted.

Let us cast a rapid glance over some of these topics of biological discussion. The fascinating subject of mimicry, involving as it necessarily does the discussion of the value of warning colours and behaviour, a subject opening up an extensive group of problems so brilliantly studied by Professor Poulton, is meaningless save in so far as there is implied a conscious reaction to colour and form on the part of animals which can learn from experience. The warning colours reinstate a conscious situation, so that, misled by appearances, a bird mistakes the mimicking insect for its nauseous “model.”

The whole range of behaviour, included under play, experimentation, and practice, on the importance of which, following the lead so ably given by Professor Groos, we have insisted, is equally meaningless, save as a means to the acquisition of serviceable experience for use in the more serious business of after-life; and experience is the establishment, through association and coalescence, of conscious situations which possess guiding value. And if, as we shall hereafter see, they may also be regarded as a means of securing pleasure, as a psychological end of behaviour, it is not less obvious that it is only through the development of consciousness that such a psychological end can have any existence.

It matters not if the particular form assumed by play and experimentation be largely dependent on instinctive tendencies. For all the phenomena of instinct, profoundly organic as are the modes of behaviour comprised under this head, definite as are the inherited co-ordinations in the most typical examples of its occurrence, have also, except in some doubtful cases, a conscious aspect. At any rate this is the case in so far as instinctive response forms the hereditary basis on which is reared a more nicely adjusted intelligent edifice, in so far as instinctive procedure is subsequently modified and guided by acquired experience, in so far as there creeps in that “little dose of judgment” which Huber found in bees, Lord Avebury attributes to ants, Dr. Peckham sees in spiders and solitary wasps, and all observers find in birds and mammals. For if in these cases instinctive behaviour were unconscious, it would, as such, remain outside experience; and if outside experience, there could be no data on which consciousness could base any modification of inherited behaviour, no opportunity of taking up the ready-formed responses into the mental synthesis and utilizing them for the wider ends of intelligent purpose.

In social behaviour there is a reciprocity of suggestion between the members of the community. And such suggestion is operative through an appeal to consciousness. However instinctive the forms of procedure may be in social insects, there remains much beyond which is hard to explain on the hypothesis that there is, in them, nothing analogous to a conscious situation; while in such vertebrates as birds and mammals we cannot but believe that consciousness is the main determinant of much behaviour which seems to imply the germs, or more than the germs, of sympathy. The little monkey I saw in Hamburg cuddling up caressingly to a wounded companion, must surely have experienced a conscious situation analogous to that which prompts a child to nestle alongside her companion in distress. And he who has seen no signs of sympathy in dogs, has either watched their behaviour in vain, or is himself lacking in sympathy.

In sexual selection by preferential mating, even if we follow Professor Groos in believing that it is a special mode of natural selection, the conscious situation is essential. If we accept the theory in any form, we must regard the adornments, antics, and display of the male as an appeal in some way to the consciousness of the female, whatever particular form the effects in that consciousness may take, whether the appeal evoke a sense of beauty, or simply be a means of exciting to the consummation of the natural end of courtship. Even if we follow Mr. Wallace in regarding plume and song as “recognition marks,” it is only by their appeal to consciousness in this way, if in no other, that they are of any biological value. And this, of course, applies equally to the whole range of his theory of recognition marks—their sole utility lies in their being a stimulus to consciousness through which the end of recognition is secured. So, too, not only the specialized behaviour which we dignify by the name of “courtship,” but every case in which mate is drawn to mate through sight, smell, hearing—any of the leading senses—testifies to the importance of consciousness in furthering an end of supreme biological importance.

And if, as Darwin urged, the “law of battle” among the males co-operates with preferential mating, as we can hardly deny, in securing strong, vigorous, and healthy fathers of the generation they beget, here, too, consciousness is an important factor. Can we conceive a “law of battle” among unconscious beings? If success in the combat were a mere matter of brute strength, it would imply some consciousness in its dull exercise. But it is more. It is also a trial of skill. Were it not so our forefathers would not have spent hours in watching a cock-fight, or laid heavy odds on their particular “fancy.”

We need not labour the theme. In the search for food or a nesting site, in the capture of prey and escape from enemies, in all that demands attention, and in all that necessitates practice, in what M. Houssay calls “the industries of animals,” and in that which Mr. Hudson calls “tradition,” consciousness has a part to play. Even plants unconsciously appeal to the consciousness of insects, birds, and mammals. Their bright, scented, nectar-bearing flowers, and their sweet, coloured fruits are means of effecting the biological ends of fertilization and the dissemination of seeds, but only on condition that their colours stimulate the sense of sight, and their scent and sweetness the senses of smell and taste. It is, perhaps, going too far to claim that, wherever sense-organs exist they imply at least some dim and rudimentary form of conscious situation of guiding value so far as it goes; for it is possible that in some cases the coalescence of elementary items of sentience has not been carried far enough to justify us in speaking of experience by which the animal can profit. But it is surely not going too far to claim that, wherever two or three such sense-organs are gathered together in any living being, there is consciousness in the midst of them, beginning to exercise that guidance which serves so markedly to differentiate the typical animal from the typical plant.

But throughout the animal kingdom, until we reach its highest development in man, the guidance of consciousness, important as it is, seems to be almost wholly subservient to a biological end, that of the preservation of the race, and for the race of the individual. Practical utility is the touchstone of animal intelligence, and of the whole range of feeling and emotion in beings still under examination in the stern school of natural selection. By this we mean that practical utility has determined what degree and complexity of intelligence, feeling, and emotion shall be attained. If the requisite level be not attained—elimination. Higher levels no doubt bring advantage—so long as they are practically useful. But in the school of natural selection useless accomplishments are not much taught. Although its examinations are in a sense competitive, all are allowed to pass who qualify for survival. But the competitors become more numerous and the standard for a pass rises. As the school increases in size higher classes with harder problems to solve are established. Progress is an incident of the constant survival of the fittest when there are variations in fitness.