DISCOUNTING CAUSES OF BEHAVIOR - ARE 2 REASONS BETTER THAN ONE

Several theories propose that people discount a cause of an action whe n other plausible causes are present. This view has recently been chal lenged, but the relevant research has not been reviewed. In this artic le, the author reviews research on factors that affect discounting and the use of conjunctive explanations. Some studies are inconclusive be cause inappropriate measures are used. Other studies fail to distingui sh between the probability, necessity, sufficiency, and relevance of c auses. When these distinctions are recognized, patterns of discounting are predictable. When causes are presented sequentially, people may u nderdiscount the prior cause, suggesting that an anchoring process may limit discounting, In other cases, discounting is absent because peop le perceive multiple causal influences on actions or because they judg e that certain causes are necessary or sufficient. Theory has assumed that causes are negatively associated, but causes may be independent o r positively associated. This conclusion challenges analogies between discounting and scientific and legal reasoning.