PSYCHOLOGICAL SCIENCE General Article WHAT IS AN "EXPLANATION" OF BEHAVIOR?

The cognitive "revolll1ion " in psychology illtroduced a new concept of explanation and somewhat novel methods ofgath-ering and illterpreting evidence. These innovations assume that it is essential to explain complex phenomena at several levels, symbolic as well as physiological; complemelltary, not compet-itive. As with the other sciences, such complementarity makes possible a comprfhensive and unified experimental psychology. Colltemporary cognitive psychology also introduced comple-memarity of another kind, drawing upon, and drawing to-gether, both the 'behaviorist and the Gestalt traditions. I would like to begin with two comments on contem-porary cognitive psychology-on where we stand. The evidence supporting these observations is so overwhelm-. ing that I will not bore you by rehearsing it. But we have some conventional, customary ways of talking about psy-chology that fly in the face of what I think are the facts, and I would like to distance myself from these ways of speaking, which I believe are harmful to the continued rapid progress of our science. How often haVe you heard that "some day we will. understand the mind, " or that ' 'the human brain is a great mystery that we must seek to solve"? In fact, psychology exists not in the future, but in the present. By any rea-sonable metric, we know more about the human mind and brain than geophysicists know about the plate tec-tonics that move the continents over the globe, far more than particle physicists know about elementary particles, or biologists about the processes that transform a fertil-ized egg into a complex multicellular organism. We discount our knowledge because some of it is so commonplace, so familiar from our everyday acquain-tance with ourselves and other people. We discount it also because it often is insufficient to permit predictions of behavior in important matters that concern us. The former is a great blessing to us, for it all~ws us to learn easily facts of sorts that other. sciences have to tease out with great effort. The latter is a true limitation that we Address correspondence and reprint requests to Herbert A. Simon