In his classic The Principles of Psychology, published in 1890, William James, who had a major role in establishing psychology as an independent field of science, defined the scope of psychology in these words: "Psychology is the Science of Mental Life, both of its phenomena and of their conditions.

Behaviorism

Compare this with the declaration in 1913 by J. B. Watson, who is generally considered the founder of the behaviorist movement: "Psychology . . . is a purely objective experimental branch of natural science. Its theoretical goal is the prediction and control of behavior."

Behaviorism

Wilfred Sellars (1912-89): Behaviorists insist on confirming “hypotheses about psychological events in terms of behavioral criteria” (1963, p. 22).

A behaviorist, so understood, is a psychological theorist who demands behavioral evidence. For such a person, there is no knowable difference between two states of mind unless there is a demonstrable difference in the behavior associated with each state.

Behaviorism

Three claims to which behaviorists have commitment

1- Psychology is the science of behavior. Psychology is not the science of mind. (Methodological)

2- Behavior can be described and explained without making reference to mental events or to internal psychological processes. The sources of behavior are external (in the environment), not internal (in the mind). (Psychological)

3- In the course of theory development in psychology, if, somehow, mental terms or concepts are deployed in describing or explaining behavior, then either (a) these terms or concepts should be eliminated and replaced by behavioral terms or (b) they can and should be translated or paraphrased into behavioral concepts. (Analytical)

Methodological behaviorism claims that psychology should concern itself with the behavior of organisms (human and nonhuman animals). Psychology should not concern itself with mental states or events or with constructing internal information processing accounts of behavior. According to methodological behaviorism, reference to mental states, such as an animal's beliefs or desires, adds nothing to what psychology can and should understand about the sources of behavior. Mental states are private entities which, given the necessary publicity of science, do not form proper objects of empirical study. Methodological behaviorism is a dominant theme in the writings of John Watson (1878-1958).

Methodological Behaviorism

Psychological behaviorism is a research program within psychology. It purports to explain human and animal behavior in terms of external physical stimuli, responses, learning histories, and (for certain types of behavior) reinforcements. Psychological behaviorism is present in the work of Ivan Pavlov (1849-1936), Edward Thorndike (1874-1949), as well as Watson. Its fullest and most influential expression is B. F. Skinner's (1904-90) work on schedules of reinforcement.

Psychological Behaviorism

Reinforcement occurs when an event following a response causes an increase in the probability of that response occurring in the future. Response strength can be assessed by measures such as the frequency with which the response is made (for example, a pigeon may peck a key more times in the session), or the speed with which it is made (for example, a rat may run a maze faster). The environment change contingent upon the response is called a reinforcer.

Reinforcement

Operant conditioning is the use of consequences to modify the occurrence and form of behavior. Operant conditioning is distinguished from classical conditioning (also called respondent conditioning, or Pavlovian conditioning) in that operant conditioning deals with the modification of "voluntary behavior" or operant behavior. Operant behavior "operates" on the environment and is maintained by its consequences, while classical conditioning deals with the conditioning of respondent behaviors which are elicited by antecedent conditions. Behaviors conditioned via a classical conditioning procedure are not maintained by consequences.

Operant Conditioning

To illustrate, consider a food-deprived rat in an experimental chamber. If a particular movement, such as pressing a lever when a light is on, is followed by the presentation of food, then the likelihood of the rat's pressing the lever when hungry, again, and the light is on, is increased. Such presentations are reinforcements, such lights are (discriminative) stimuli, such lever pressings are responses, and such trials or associations are learning histories.

An Example

A statement about a person's mental state, such as the statement that a person believes that it is going to rain or is feeling a pain in his elbow just means the same as, it can be translated into, a set of statements about that person's actual and possible behavior. It need not be translatable into statements about presently existing behavior, for a person might have a pain or a belief that he was not then and there manifesting in behavior, but then the statement has to be translatable into a set of hypothetical statements about behavior, what the agent would do or would say under such and such circumstances.

Logical Behaviorism

Analytical or logical behaviorism says that the very idea of a mental state or condition is the idea of a behavioral disposition or family of behavioral tendencies. When we attribute a belief, for example, to someone, we are not saying that he or she is in a particular internal state or condition. Instead, we are characterizing the person in terms of what he or she might do in particular situations or environmental interactions. Analytical behaviorism may be found in the work of Gilbert Ryle (1900-76) and the later work of Ludwig Wittgenstein (1889-51).

Logical Behaviorism

According to a typical behaviorist analysis, to say that Jones believes it is going to rain just means the same as saying an indefinite number of statements such as the following: if the windows in Jones's house are open, he will close them; if the garden tools are left outside, he will put them indoors; if he goes for a walk he will carry an umbrella or wear a raincoat or both; and so forth.

An Example

Analytical behaviorism traces its historical roots to the philosophical movement known as Logical Positivism (see Smith 1986). Logical positivism proposes that the meaning of statements used in science should be understood in terms of experimental conditions or observations that verify their truth. This positivist doctrine is known as “verificationism.” In psychology, verificationism underpins or grounds analytical behaviorism, namely, the claim that mental concepts refer to behavioral tendencies and so must be translated into behavioral terms.

Roots of Behaviorism

Psychological behaviorism's historical roots consist, in part, in the classical associationism of the British Empiricists, foremost John Locke (1632-1704) and David Hume (1711-76). According to classical associationism, intelligent behavior is the product of associative learning. As a result of associations or pairings between perceptual experiences or stimulations on the one hand, and ideas or thoughts on the other, persons and animals acquire knowledge of their environment and how to act. Associations enable creatures to discover the causal structure of the world. Association is most helpfully viewed as the acquisition of knowledge about relations between events. Intelligence in behavior is a mark of such knowledge.

Roots of Behaviorism

Classical associationism relied on introspectible entities, such as perceptual experiences or stimulations as the first links in associations, and thoughts or ideas as the second links. Psychological behaviorism, motivated by experimental interests, claims that to understand the origins of behavior, reference to stimulations (experiences) should be replaced by reference to stimuli (physical events in the environment), and that reference to thoughts or ideas should be eliminated or displaced in favor of reference to responses (overt behavior). Psychological behaviorism is associationism without appeal to mental events.

Psychological Behaviorism

In its historical foundations, methodological behaviorism shares with analytical behaviorism the influence of positivism.

Roots of Behaviorism

Problems Associated with Behaviorism

Methodological Problems

Chomsky claimed that the idea that when we study psychology we are studying behavior is as unintelligent as the idea that when we study physics we are studying meter readings. Of course we use behavior as evidence in psychology, just as we use meter readings as evidence in physics, but it is a mistake to confuse the evidence that we have about a subject matter for the subject matter itself. The subject matter of psychology is the human mind, and human behavior is evidence for the existence and features of the mind, but is not itself the mind.

Logical Problems

Behaviorists would analyze Jones's belief that it is going to rain into sets of statements about his rain-avoidance behavior. But the difficulty with that is that we can only begin to make such a reduction on the assumption that Jones desires to stay dry. So the assumption that Jones will carry an umbrella if he believes that it is going to rain is only plausible if we suppose that Jones does not want to be rained on. But then if we are analyzing belief in terms of desire, it looks like there is a kind of circularity in the reduction. We did not really reduce the belief to behavior; we reduced it to behavior plus desire, which still leaves us with a mental state that needs to be analyzed.

Logical Problems

A second family of difficulties had to do with the causal relations between mental states and behavior. The logical behaviorists had argued that mental states consisted in nothing but behavior and dispositions to behavior, but this runs against our common sense intuition that there is a causal relation between our inner mental states and our outward behavior. My pain causes me to cry out and to take aspirin; my belief that it is going to rain and my desire to stay dry cause me to take an umbrella, etc., and it seems that this apparent truth is denied by the behaviorists. They cannot account for the causal relations between the inner experience and the external behavior, because they are in effect denying that there is any internal experience in addition to the external behavior.

The Real Problem

The real difficulty with behaviorism, though, is that its sheer implausibility became more and more embarrassing. We do have thoughts and feelings and pains and tickles and itches, but it does not seem reasonable to suppose that these are identical with our behavior or even with our dispositions to behavior. The feeling of pain is one thing, pain behavior is something else.

Psychological Problems

The deepest and most complex reason for behaviorism's decline in influence is its commitment to the thesis that behavior can be explained without reference to non-behavioral mental (cognitive, representational, or interpretative) activity. Behavior can be explained just by reference to its “functional” (Skinner's term) relation to or co-variation with the environment and to the animal's history of environmental interaction. Neurophysiological and neurobiological conditions, for Skinner, sustain or implement these functional relations. But they do not serve as ultimate or independent sources of behavior.