Animal Life and Intelligence

by C. Lloyd Morgan

The broadest division of the feelings is, therefore, into pleasurable on the one hand, and painful on the other.

Another general question with regard to the feelings is—With what condition or state of the bodily organization are they associated? In answer to this question we may say (1) that any very violent and abnormal stimulus produces pain; (2) that the conditions of pleasure are to be sought within the limits of the healthy and normal exercise of the bodily functions and mental activities; (3) that within these limits the changes of activity consequent upon the rhythmic flow of normal organic processes bring with them, in the aggregate, pleasure, the delight of healthy life; (4) that within these limits, again, we experience pleasure or pain, enjoyment or weariness, ease or discomfort, happiness or unhappiness, with the continued rise and fall of our life-tide. For, as Spinoza says, "We live in perpetual mutation, and are called happy or unhappy according as we change for the better or the worse." So long as our activities remain at a dead level, there is indifference—neither pleasure nor pain. A rise of the tide of activity brings pleasure, a fall the reverse. Lastly, we may say (5) that beyond the limits of healthy and normal exercise there is, on the one hand, excessive exercise which, carried far enough, may give rise, first to fatigue, and then to acute pain; and, on the other hand, deficient exercise, which may produce that dull and numb form of pain which we call discomfort, or a sense of craving or want.

Pleasures and pains may thus be either massive or acute, diffused or locally concentrated. On the whole, we may say, with Mr. Grant Allen,[HG] that "the acute pains, as a class, arise from the action of surrounding destructive agencies; the massive pains, as a class, from excessive function or insufficient nutriment." But since massive pains, when pushed to an extreme, merge into the acute class, "the two classes are rather indefinite in their limits, being simply a convenient working distinction, not a natural division." "Massive pleasure can seldom or never attain the intensity of massive pain, because the organism can be brought down to almost any point of innutrition or exhaustion; but its efficient working cannot be raised very high above the average. Similarly, any special organ or plexus of nerves can undergo any amount of violent disruption or wasting away, giving rise to very acute pains; but organs are very seldom so highly nurtured and so long deprived of their appropriate stimulant as to give rise to very acute pleasure." The amount of pleasure varies, according to Mr. Grant Allen, whose discussion of the subject is, perhaps, the best and clearest we have, directly as the number of nerve-fibres involved, and inversely as the natural frequency of their excitation. No doubt the principles above sketched out are somewhat vague and general; but we are scarcely justified in formulating any that are more precise and exact.

Accepting now the theory of evolution, we may say, furthermore, that during the long process of the moulding of life to its environment, there has been a constant tendency to associate pleasure with such actions as contribute towards the preservation and conservation of the individual and the race, and to associate pain with such actions as tend to the destruction or detriment of the individual or the race. For there can be little doubt that pleasure and pain are the primary incentives to action. Without the association of pleasure with conservative action, and pain with detrimental action, it is difficult to conceive how the evolution of conscious creatures would be possible. Conservative action, if it is to be persisted in by a conscious creature, must be associated directly or indirectly with pleasurable feelings; nay, more, if it is to be persistently persevered in, its non-performance must be associated with that dull form of pain which we call a craving or want. Only under such conditions could activities which tend to the survival of the individual and the race be fostered and furthered.

It must be remembered, however, that such association is founded on experience, and has no necessary validity beyond experience. That quinine, though unpleasant to the taste, is, under certain circumstances, beneficial to the individual, and that acetate of lead, though sweet-tasted, is harmful, cannot be fairly urged in opposition to this principle, since the effects of these drugs form no part of the normal experience of the individual and the race. Nor can it be fairly objected that animals transported to new countries often eat harmful and poisonous plants presumably because they are nice; for these plants form part of an unwonted environment. Nor, again, is the fact that the association of pleasure with conservative action and pain with harmful action is not always perfect, in any sense fatal to the general principle. For the establishment of the association is still in progress; and with the increase in the complexity of life its accurate establishment is more and more difficult. No one is likely to contend that what appears to be a general principle must also be an invariable rule. The general principle is that under the joint influence of pleasure (attractive) and pain (repellent) the needle of animal life sets towards the pole of beneficial action. That the needle does not always point true only illustrates the fact that life-activities are still imperfect.

Let us notice that it is under the joint action of pleasure and pain that the needle sets. We must not think only of the positive aspect, and neglect the negative. What we know as wants, cravings, appetites, desires, and dissatisfactions, are dull and continuous pains,[HH] which tend to drive us to actions by which they shall be annulled, and the performance of which shall give us the pleasures of gratification. Dr. Martineau regards a felt want as a mainspring of our energy. "Life," he says,[HI] "is a cluster of wants, physical, intellectual, affectional, moral, each of which may have, and all of which may miss, the fitting object. Is the object withheld or lost? There is pain: is it restored or gained? There is pleasure: does it abide or remain constant? There is content. The two first are cases of disturbed equilibrium, and are so far dynamic that they will not rest till they reach the third, which is their posture of stability and their true end." To this I would only add that the content which follows on the keen pleasure of satisfaction is evanescent, and ere long lapses into indifference, on which in due time follows the dull pain resulting from the recurrent pressure of the want or desire.

It is clear that, in introducing these wants and desires, we are entering the sphere of the emotions, and it is sometimes said that the emotions have their basis in pleasure and pain. If by this it is meant that the emotions often exhibit more or less prominently one or other of these two aspects of feeling, we may agree with the statement. It will be well, however, to lead up to our consideration of the emotions by taking a general review of the manner in which the organism responds to external stimuli.

A dog is lying dreamily on the lawn in the sunshine. Suddenly he raises his head, pricks his ears, scents the air, looks fixedly at the hedge, and utters a low growl. Place your hand upon his shoulder, and you will find that his muscles are all a-tremble. He can restrain himself no longer, and darts through the hedge. You follow him, look over the hedge, and see that it is his old enemy, the butcher's cur. They are moving slowly past each other, head down, teeth bared, back roughened. You whistle softly. Such a whistle would generally bring him bounding to your feet. But now it is apparently unheard. The two dogs have a short scuffle, and the cur slinks off. Your dog races after him; but after a few minutes returns, jumps up at you playfully, and then lies down again on the grass. But every now and then, for ten minutes or so, he raises his head and growls softly.

Let us briefly analyze the dog's actions, reading into them, conjecturally, the accompaniments in consciousness. As he lies on the lawn, he receives a sense-stimulus, auditory or olfactory, which gives rise to the construction of the percept dog (perhaps particularized through olfactory discrimination). About the formation of constructs or percepts, however, we have already said enough; we have now to consider their effects. The head is raised, the ears pricked, and so on. The dog is on the alert. His attention is roused. What are the physiological effects? Certain motor-activities or tendencies to activity. These are of two kinds—first, in connection with the sense-organs, the muscles of which are brought into play in such a way as to bring the organs to bear upon the exciting object; secondly, in connection with many other muscles, which are innervated, so as to be ready to act rapidly and forcibly. The first motor-effect, that on the muscles of the sense-organs, is a very characteristic physical concomitant of the psychological state which we term "attention;" the second effect, the incipient innervation of muscles likely to be called into play, is equally characteristic of the psychological state we call alertness.

Meanwhile an emotional state is rising in the mind of the dog. We may call it, conjecturally, anger and combativeness. But what we name it does not much signify for our present purpose. It has a growing tendency to work itself out in a series of definitely directed actions. And this reaches its point of culmination when the dog rushes through the hedge and stands with bared teeth before his antagonist. A whole set of appropriate muscles are now strongly innervated. There is probably a double innervation—an innervation prompting to activity and an innervation inhibiting or restraining from activity. The attention is so concentrated that he heeds not, probably hears not, his master's whistle. He is keenly on the alert. Then he sees his chance; the inhibition or restraint is withdrawn, and he flies at his opponent. The emotional tendency works itself out in action. Even after he has resumed his place on the lawn, memories of the emotional state return, and lead him to lift his head, slightly bare his teeth, and growl.