Rational behaviour in everyday situations

Rational choice theorists are divided on what the most adequate version of rational choice theory is and on the kinds of behaviour it can explain. Furthermore, scholarly evidence differs with respect to which decision rules are predominantly used by individuals. Present versions of rational choice theory can be placed on a continuum ranging from a neoclassical economic model of man to a 'soft' bounded rationality model. Depending on the model the answers to the following questions differ: Do people calculate or is most behaviour habitual? To what extent are existing behavioural alternatives, behavioural consequences, and probabilities considered? Do individuals use decision heuristics and, if so, which ones? In order to answer these questions we have conducted an empirical study on everyday behaviour such as buying a car or a computer, travelling to a certain destination, choosing a place for a vacation, going to a restaurant, and choosing one's occupation. The major results are that decision situations exhibit a low complexity, and decision processes can be described by three major decision heuristics. The dominant type is binary-sequential. Furthermore, in everyday behaviour individuals perceive fewer behavioural alternatives, but unexpectedly they consider more behavioural consequences and probabilities than in other behaviours. The paper suggests an explanation for this finding. Another finding is that the decision process for everyday behaviour extends mostly over one phase only. In the final section, consequences for rational choice theory are discussed.