Prediction and the partial understanding of the law of large numbers

Abstract

We examined people's understanding of the implications of the law of large numbers for prediction of social behavior and abilities. We found that people possess a partial understanding of the law: They sometimes recognize that one can predict more confidently from larger samples, but do not recognize that one can predict more confidently to larger samples. This partial understanding was reflected not only in the predictions subjects made, but also in the explanations they constructed to account for their predictions. It appears that people's intuitions include the notion that increasing the size of the predictor sample of events increases predictability, whereas they do not include the notion that increasing the size of the predicted sample of events increases predictability.