Abstract Studies of irrationality in cognitive psychology have usually looked at areas where humans might be expected to be rational, yet appear not to be. In this paper the other extreme of human irrationality is examined: the delusion as it occurs in psychiatric illness. A parallel is suggested between the delusion as an aberration of cognition and some illusions which result from aberrations within optics. It is argued that, because delusions are found predominantly within certain limited areas of cognitive functioning, (...) they may represent a form of mental aberration which may tell us something about the abstract properties of mind. Possible implications of this model for several areas of cognitive science are discussed. (shrink)

ABSTRACT Since the 1970s there has been a significant paradigm shift in psychology away from behaviourism and towards cognitive psychology. Indeed a recent survey discovered that by 1983 more than half American psychologists were describing their approaches as cognitive. However, while behaviourism has had an identifiable philosophical ‘line’ in positivism, reductionism and the hypothetico‐deductive model, such a framework has been noticeably lacking from cognitive psychology. A view of cognitive psychology based on functionalism and ideas from systems analysis is put forward.

Sociobiology has always had a strong relationship with classical psychometrics, and with intelligence testing in particular. The major ideological impact of Eugenics prior to 1940 led many psychometricians to adopt a sociobiological perspective, but when this turned out, in the 1960's, to be controversial many of the procedures of classical psychometrics were abandoned. Their place was taken by functional psychometrics, based on criterion reference testing, where the content of test items was related directly to very specific skills which may be (...) required in the work place or other setting, and the use of intervening psychological traits such as intelligence was eliminated. It is demonstrated here that much of the theory of traits can be derived directly from functional psychometrics, without the need to make any sociobiological presuppositions. (shrink)