ABSTRACT
Traditional psychology rests on a set of basic categories that are seldom questioned. They form the major headings in all our introductory texts: learning, motivation, memory, emotion, personality, development, sensation, perception, etc. We sometimes acknowledge problems in defining them but don’t normally allow ourselves to become preoccupied with those problems. The norm in this century has been to seek procedural rules by which definitions can be fixed and agreed upon so that we can ‘get on with the business’ of doing psychology. Perhaps the best known means of achieving such expediency have been provided by the operational definition. When we undertake an investigation of, say, learning or perception, we generally accept the definitions given by the current textbooks and experimental literature-indeed, we know very well we won’t get published if we don’t!
