Instrumental Conditioning: Skinner and Operant Behavior

Skinner and Operant Behavior

Thorndike initiated the experimental study of instrumental behavior; but, unquestion-ably, the psychologist who shaped the way most modern learning theorists think about the subject was B. F. Skinner (1904–1990; Figure 7.20). Skinner was one of the first theorists to insist on a sharp distinction between classical and instrumental condition-ing. He noted that in classical conditioning, the animal’s behavior is elicited by the US. Salivation, for example, is set off by an event outside the organism. But in instrumen-tal conditioning, Skinner argued, the organism is much less at the mercy of external factors. Its reactions are emitted from within, as if they were what we ordinarily call “voluntary.” Skinner called these instrumental responses operants:They operate on the environment to bring about some change that leads to some consequence. And, in Skinner’s view, these consequences are crucial. Like Thorndike, Skinner argued that an operant followed by a positive consequence was more likely to be emitted in the future, while an operant followed by a negative consequence was less likely to be emitted again (Skinner, 1938).

Skinner believed, however, that Thorndike’s procedure for studying learning was inefficient. Rather than placing animals in a puzzle box (which required many minutes for each learning trial), Skinner sought a procedure in which the instrumental response could be performed repeatedly and rapidly, so that data could be gathered more easily. Many of his studies therefore employed an experimental chamber (popularly called the Skinner box) in which a rat presses a lever or a pigeon pecks at a lighted key in order to gain a reward (Figure 7.21). In these situations, the animal stays in the chamber for a set interval—perhaps an hour at a time—and during that interval, we track the animal’s behavior by recording its response rate—the number of lever presses or key pecks per unit of time.