Heuristic decision making with incomplete information: Conditions for ecological rationality

Ecological rationality is the study of when certain decision making strategies exploit specific environments so efficiently that further information and computation would not necessarily increase accuracy. This perspective challenges many of the normative accounts of rationality by arguing that heuristics, i.e. decision making strategies that ignore some available information, in some environments can make decisions faster, more efficiently, and/or more accurately than analytic decision making strategies. The challenge for many researchers and proponents of ecological rationality is to determine when heuristics are ecologically rational. Research has previously identified some important environmental structures: uncertainty, redundancy, sample size, and variability in weights. This paper introduces a new environmental structure, a measure of distribution of incomplete information called complete attribute pairs, and shows how this structure indicates when two well-studied heuristics, Take-the-Best (TTB) and Tallying, are ecologically rational under conditions of incomplete information. Specifically this paper presents the results of a simulation measuring the accuracy and effort of TTB and Tallying alongside two analytic decision making strategies, weighted-additive (WADD) and equal weighting (EW), in scenarios with incomplete information, showing that the analytic strategies were almost invariant to changes in complete attribute pairs while increases in complete attribute pairs increased the accuracy of TTB and Tallying. These results identify complete attribute pairs as a parameter that is potentially capable of indicating ecological rationality of TTB and Tallying.