Story of Psychology - Morton Hunt [181]
Tolman then put a barrier across the straight path halfway to the goal so that the rat could reach it only by the longest route. According to theory, when the rat ran down the straight path and came up against the barrier, it should have turned back and tried the next most easily established habit—the medium-length route—but it immediately took the long route. To Tolman this suggested that the rat had built up a sort of mental map of the entire maze and “realized” that the barrier blocked all but the longest route.70
Tolman conducted many similar experiments, most of them far more complicated, and all of which supported his belief that “something like a field map of the environment gets established in the rat’s brain.” Standard behaviorist theory, he said, offered only a partial explanation of maze learning: “We agree… that the rat in running a maze is exposed to stimuli and is finally led as a result of these stimuli to the responses which actually occur. We feel, however, that the intervening brain processes are more complicated, more patterned, and often, pragmatically speaking, more autonomous than do the stimulus-response psychologists.”71
These studies led Tolman to propound a theory he called “purposive behaviorism.” Its essence was that rats act not as automata, developing habits solely according to the number and kind of stimuli they experience, but as if, in addition, they are influenced by their own expectations, their knowledge of what leads to what in a given situation, their goals, and other internal processes or states.72 As one orthodox behaviorist derisively said, Tolman’s rats were “buried in thought.”73
Tolman called these internal factors “intervening variables” (they intervened between stimulus and response) and insisted that they were compatible with behaviorism. “For the behaviorist,” he wrote, “‘mental processes’ are to be identified and defined in terms of the behaviors to which they lead. [They are] naught but inferred determinants of behavior… Behavior and these inferred determinants are both objective, defined types of entity.”74 It was a valiant effort to remain faithful, but Tolman had, willy-nilly, breached the dike of behaviorism and let in a trickle of mind. In time it would be a flood.
If reward and repetition only partly explain rat behavior, they give an even more limited account of the determinants and workings of human behavior. Consider memory, for example. Behaviorists portrayed it in purely mathematical terms: the more trials and reinforcements, the greater the rewards, the closer in time the S and the R, the more certain it is that the S will produce the R. If the stimulus is the question “What comes after five?,” the response is “six.” If the stimulus is the question “What is your phone number?,” the answer is a sequence of seven digits (ten if you include the area code). The first digit is the response to the question but is also the stimulus that produces the response of the second digit, and so on, in a chain of associative links.
But even at the height of the behaviorist era, psychologists knew that human memory was more complicated than that. For one thing, we “chunk” some information: we remember area codes, for instance, as units, not as a series of linked responses. For another thing, we have different kinds of memory: we learn some phone numbers only for a moment—we look them up, hold them in “short-term memory” until we dial, and then instantly forget them, but make others a part of our