Discounting in Multicausal Attribution: The Principle of Minimal Causation

Abstract

A series of three experiments investigated the effect of information about one possible cause of an event on inferences regarding another possible cause. Experiment 1 showed that the presence of a second possible cause had no effect on the perceived probability that the first possible cause influenced the event. However, if the second cause is cited as having definitely influenced the event, then the probability that the first possible cause influenced the event is reduced. Experiment 2 showed that the presence of a second possible cause does reduce the judged probability that a given cause was present at the time of an event. The final experiment revealed that the tendency (found in Experiment 1) to discount the involvement of the first cause given the involvement of a second cause diminishes when subjects were more highly motivated and confronted with their own discounting. These results are inconsistent with Kelley’s account of discounting and provide some support for a proposed explanatory heuristic, the principle of minimal causation. Users of this principle analyze a situation until they have identified a minimal set of sufficient causes; other possible causes are ignored or dismissed.

(Report No. 77-11)