Variable decision strategies, rational choice, and situation-related travel demand

Classical economic theory following Bentham and Mill assumes decision makers are completely informed, highly sensitive to differences between alternatives, and above all rational in being able to rank order the possible alternatives and choose among them on some measure of welfare (utility maximization). In recent years, this view has been successfully challenged by empirical studies of decision making, and many alternative decision rules have emerged (such as lexicographic, elimination by aspects, counting, conjunctive, heuristic additive difference, affective, take the best, and so on). Despite thirty years' work on boundedly rational and cognitive approaches, the classical view is still widely accepted in urban travel demand modeling. This paper develops a newer conceptual framework for shopping travel situtationsönamely, choice of shopping place on different kinds of tour, for different orders of goods, and for regional malls and neighborhood centers. Hypotheses concerning the use of different kinds of decision rule are generated for the different situations or contexts. A statistical design is provided for tests of these hypotheses using fieldwork, verbal protocol analysis, and low-level t-tests. Fifty-five MIT students are interviewed, and their protocols for the shopping situations recorded and analyzed. The findings are that decision rules are multiple and vary with context. Although the specific hypotheses of the paper are not strongly supported, there is overwhelming evidence of the widespread use of simple heuristics. Implications of the findings are drawn for future work in the travel demand field and the preference and choice field. In addition, the contribution of this paper to behavioral decision making is noted, through the extension of work on choice heuristics to a different field (travel demand) and the use of a fieldwork qualitative methodology. doi:10.1068/a39287