Social judgments of spurious and causal relations between attributes and outcomes

People can learn about relations between attributes and outcomes by observing the attributes and outcomes of others, but, as this experiment indicates, such learning is not always veridical. Each subject received information about the ages, educations, and salaries of groups of employees in a fictitious corporation. Within a group, either age or education was related to salaries and the two attributes were either orthogonal or correlated. In each case, subjects judged the strength of the causal relation between each attribute and salaries. The results confirmed our hypothesis that observers are more likely to view a causally relevant attribute as irrelevant, and a causally irrelevant attribute as relevant, when relevant and irrelevant attributes are correlated. However, this tendency seemed to be mediated by subjects' bias to prefer education as an explanation of salary differences: That is, when age and education were correlated, subjects tended to view education as relevant even when it was irrelevant and age as irrelevant even when it was relevant. The results suggest that when attributes are correlated, factors extraneous to observed data may have a major influence on inferred attribute-outcome associations.