Conjunctive Explanations of Success and Failure: The Effect of Different Types of Causes

The finding in previous research that people rate conjunctions of causes as more probable for success and completed actions than for failure and failed actions has been explained in terms of the characteristics of success and failure. However, the higher ratings for success may have occurred because the research measured causes that are individually associated with success (e.g., ability) and omitted causes associated with failure (e.g., task difficulty). The present studies with achievement and action outcomes determined whether the ratings found with success-related causes generalized to failure-related causes. Conjunctions of internal causes and task-related goals were rated as more probable for success than failure, but conjunctions of external causes and competing goals were rated as more probable for failure than success. These results suggest that the perceived probability of a conjunction is significantly affected by the selection of causes included in the conjunction.