ABSTRACT
Defining concepts in terms of publically visible ‘operations’ or criteria. Introduced by the American philosopher of science P.W. Bridgman in 1927 and closely related (though independently formulated) to the logical positivist notion of the verification criterion of meaning. Rapidly became popular among behaviorist psychologists as a way of evading the ‘private’ nature of many psychological phenomena and rendering hypotheses ‘verifiable’. Thus ‘hunger’ in the rat may be defined in terms of hours of food deprivation, intelligence as ‘performance on an intelligence test’, suggestibility by performance on the ‘rod and frame’ test. Although pragmatically useful, operationalism lost its authority with the philosophical decline of logical positivism.
