The psychology of linear judgement models

Abstract

The ordinary policy capturing paradigm that focuses on cue-judgement relations is too limited to serve as a basis for a theoretical understanding of human judgement. To get on, we need a Brunswikian approach with a representation of both the task and the judge. Three stable results from studies with linear models are discussed from that perspective. Following Einhorn et al. (1979), the result that linear models usually fit judgement data well is explained by reference to the fact that linear models capture an essential feature of human judgement, viz., vicarious functioning. For the result that judges are inconsistent and that inconsistency varies with the predictability of the judgement task, the theory of quasi-rationality proposed by Hammond and Brehmer (1973) is invoked. Finally, it is argued that the wide interindividual differences in policies usually found show that the level of analysis is inappropriate. A given level of achievement can be reached by many different combinations of weights, and we should not be surprised to find wide interindividual differences at the policy level. We must search for stability at the level of achievement and those aspects that affect achievement, rather than at the level of cue utilisation coefficients.