Explanatory versatility and exclusivity as principles of causal judgement

This research is concerned with the role in causal judgment of information pertaining to prior causal beliefs. Evidence is reported that the judged likelihood that a given cause was responsible for a given effect increases as the number of other effects attributable to that cause and present on that occasion increases. It was also found that the judged likelihood that a cause was responsible for a given effect decreased as the number of effects attributable to an alternative cause increases. These judgmental tendencies are termed the principles of explanatory versatility and explanatory exclusivity, respectively. It is argued that these principles, which are independent of explanatory coherence, are most likely to be used when cues to causal mechanisms are not available and when people possess relevant prior beliefs about possible effects of the candidate causes