Rational Analysis and Human Variation

Rational analysis is a research program in psychology that tries to understand the mind by identifying the problems it is attempting to solve and deriving optimal solutions to those problems. The optimal solutions are then used to build models and make predictions about human behavior (Anderson 1990). In this paper, I examine the potential of rational analysis to shed light on individual differences. Taking the rational analysis of causal learning as a case study, I argue that rational modelers usually ignore psychological variation or describe it in a way that is scientifically stultifying and ethically problematic. But rational analysis doesn’t have to be this way. There are many ways to accommodate individual differences in rational models. Moreover, the principle of charity on which rational analysis is based is particularly appropriate for the study of human variation. I advocate for an approach I call the “rational analysis of variation,” whose practitioners ask: how might people’s different behavior make sense given their different experiences, situations, and goals? I propose several methodological principles for this approach and illustrate its application to the study of causal learning.