EXPLANATORY VERSATILITY AND EXCLUSIVITY AS PRINCIPLES OF CAUSAL JUDGMENT

This research is concerned with the role in causal judgment of informa tion pertaining to prior causal beliefs. Evidence is reported that the judged likelihood that a given cause was responsible for a given effe ct increases as the number of other effects attributable to that cause and present on that occasion increases. It was also found that the ju dged likelihood that a cause was responsible for a given effect decrea sed as the number of effects attributable to an alternative cause incr eases. These judgmental tendencies are termed the principles of explan atory versatility and explanatory exclusivity, respectively. It is arg ued that these principles, which are independent of explanatory cohere nce, are most likely to be used when cues to causal mechanisms are not available and when people possess relevant prior beliefs about possib le effects of the candidate causes.