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In psychology, the picture is admittedly more complex. Since the publication of Freud's earliest metapsychological writings, and in particular his adumbration of the distinction between two principles of mental functioning, the BEHAVIORAL AND BRAIN SCIENCES (2003) 26, 139-198 Abstract: Rational choice theory enjoys unprecedented popularity and influence in the behavioral and social sciences, but it generates intractable problems when applied to socially interactive decisions. In individual decisions, instrumental rationality is defined in terms of expected utility maximization. This becomes problematic in interactive decisions, when individuals have only partial control over the outcomes, because expected utility maximization is undefined in the absence of assumptions about how the other participants will behave. Game theory therefore incorporates not only rationality but also common knowledge assumptions, enabling players to anticipate their co-players' strategies. Under these assumptions, disparate anomalies emerge. Instrumental rationality, conventionally interpreted, fails to explain intuitively obvious features of human interaction, yields predictions starkly at variance with experimental findings, and breaks down completely in certain cases. In particular, focal point selection in pure coordination games is inexplicable, though it is easily achieved in practice; the intuitively compelling payoff-dominance principle lacks rational justification; rationality in social dilemmas is self-defeating; a key solution concept for cooperative coalition games is frequently inapplicable; and rational choice in certain sequential games generates contradictions. In experiments, human players behave more cooperatively and receive higher payoffs than strict rationality would permit. Orthodox conceptions of rationality are evidently internally deficient and inadequate for explaining human interaction. Psychological game theory, based on nonstandard assumptions, is required to solve these problems, and some suggestions along these lines have already been put forward.Keywords: backward induction; Centipede game; common knowledge; cooperation; epistemic reasoning; game theory; payoff dominance; pure coordination game; rational choice theory; social dilemma Andrew M. Colman is Professor of Psychology at the University of Leicester, UK. He received his Ph.D. from Rhodes University in South Africa, and he taught at Cape Town and Rhodes Universities before emigrating to England in 1970. His publications include more than 120 articles and chapters, on cooperative reasoning in games and other topics, and several books, the most relevant of which are Game Theory and its Applications in the Social and Biological Sciences (2nd edn, 1995) and an edited volume entitled Cooperation and Competition in Humans and Animals (1982). His latest book is the Oxford Dictionary of Psychology (2001). Were such things here as we do speak about? Or have we eaten on the insane root That takes the reason prisoner?- Macbeth (I.iii.84) reality prin...

via the Internet (amc@leicester.ac.uk).Summary.-Using a self-administered questionnaire, 227 respondents rated service elements associated with a restaurant, retail store, or public transport company on several 5-point and 7-point rating scales. Least-squares regression showed that linear equations for estimating 7-point from 5-point and 5-point from 7-point ratings explained over 85% of the variance and fitted the data almost as well as higher-order polynomials and power functions. In a cross-validation on a new data set, the proportion of variance explained fell to about 76%. Functionally inverse versions of the derived linear equations were calculated for the convenience of researchers and psychometricians.

When tackling antimicrobial resistance, the tensions between immediate individual risks and long-term collective risks need to be taken into account. Efforts to reduce diagnostic uncertainty and to change risk perceptions will be critical in shifting practice.

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