Conjoint respondents as adaptive decision makers

Jon Martin Denstadli
Institute of Transport Economics

Rune Lines
Norwegian School of Economics and Business Administration

INTRODUCTION

This paper explores the decision rules used by respondents in order to arrive at preference judgements for a set of conjoint product profiles. Implicit in most research and practical applications of conjoint measurement is the assumption that respondents use some form of weighted additive judgement rule. This implies that the respondent combines the information in a conjoint profile into an overall evaluation that in turn forms the basis for his/her preference statement or choice (for choice based conjoint). Research on human judgement and information processing in other substantive domains indicates that this assumption might be only partially true. This research suggests that people often use simpler rules in order to process information from multi-attribute objects. Among the simplified rules (compared to weighted additive) that have been identified are the lexicographic heuristic, the elimination by aspects heuristic, and the disjunctive and conjunctive judgement rules (see e.g. Bettman et al. 1998 for a review). Thus, contrary to a rational perspective on human decision making, where decision makers are supposed to use an invariant algorithm in their choices, information processing theory purports that people are adaptive decision makers who possess a repertoire of different strategies in making choices.