Laws of Behavior in General
Behavior is predictable. The first law of behavior, one fraction of the general law of the uniformity of nature, is that with life and mind, as with mass and motion, the same cause will produce the same effect,—that the same situation will, in the same animal, produce the same response,—and that if the same situation produces on two occasions two different responses, the animal must have changed.
Scientific students of behavior will, with few exceptions, accept this law in theory, but in practice we have not fully used it. We have too often been content to say that a man may respond in any one of several ways to the same situation, or may attend to one rather than another feature of the same object, without insisting that the man must in each case be different, and without searching for the differences in him which cause the different reactions.
The changes in an organism which make it respond differently on different occasions to the same situation range from temporary to permanent changes. Hunger, fatigue, sleep, and certain diseases on the one hand, and learning, immunity, growth and senility on the other, illustrate this range.
Behavior is predictable without recourse to magical agencies. It is, of course, the case that any given difference between the responses of an animal to the same situation depends upon some particular difference in the animal. Each immunity, for example, has its detailed representation in an altered condition of the blood or other bodily tissue. In general the changes in an animal which cause changes in its behavior to the same situation are fully enumerated in a list of the bodily changes concerned. That is, whatever changes may be supposed to have taken place in the animal’s vital force, spiritual essence, or other magical bases for life and thought, are useless for scientific explanation and control of behavior.
No competent thinker probably doubts this in the case of such changes as are referred to by hunger, sleep, fatigue, so-called ‘functional’ diseases and immunity, and those who do doubt it in the case of mental growth and learning seem to represent an incomplete evolution from supernatural, or rather infrascientific, thinking. There may be in behavior a surplus beyond what would be predictable if the entire history of every atom in the body was known—a surplus necessarily attributable to changes in the animal’s incorporeal structure. But scientific thinkers properly refuse to deliberately count upon such a surplus.
Every response or change in response of an animal is then the result of the interaction of its original knowable nature and the environment. This may seem too self-evident a corollary for mention. It should be so, but, unfortunately, it is not. Two popular psychological doctrines exist in defiance of it. One is the doctrine that the movements of early infancy are random, the original nature of the animal being entirely indifferent as to what movement shall be made upon a given stimulus. But no animal can have an original nature that does not absolutely prescribe just what the response shall be to every stimulus. If the movements are really random, they occur by virtue of some force that works at random. If the movements are really the result of the action of the environment on the animal’s nature, they are never random. A baby twiddles his thumbs or waves his legs for exactly the same sort of reason that a chick pecks at a worm or preens its wing.
The other doctrine which witnesses to neglect of the axiom that behavior is the creation of the environment, acting on the animal’s nature, is the doctrine that the need for a certain behavior helps to create it, that being in a difficulty tends in and of itself to make an animal respond so as to end the difficulty.
The truth is that to a difficulty the animal responds by whatever its inherited and acquired nature has connected with the special form of difficulty and that in many animals the one response of those thus provided which relieves the difficulty is selected and connected more firmly with that difficulty’s next appearance. The difficulty acts only as a stimulus to the animal’s nature and its relief acts only as a premium to the connection whereby it was relieved. The law of original behavior, or the law of instinct, is then that to any situation an animal will, apart from learning, respond by virtue of the inherited nature of its reception-, connection- and action-systems.
The inquiry into the laws of learning to be made in this essay is limited to those aspects of behavior which the term has come historically to signify, that is, to intellect, skill, morals and the like.
For the purposes of this essay it is not necessary to decide just what features of an animal’s behavior to include under intellect, skill, morals and the like. The statements to be made will fit any reasonable dividing line between behavior on the one side and mere circulation, digestion, excretion and the like on the other. There should in fact be no clear dividing line, since there is no clear gap between those activities which naturalists have come to call behavior and the others.
The discussion will include: First, a description of two laws of learning; second, an argument to prove that no additional forces are needed—that these two laws explain all learning; and third, an investigation of whether these two laws are reducible to more fundamental laws. I shall also note briefly the consequences of the acceptance of these laws in one sample case, that of the study of mental evolution.