Proceedings of the Annual Meeting of the Cognitive Science Society

This study describes a psychological experiment on biases that people exhibit in refining probabilistic causal knowledge. In the experiment, the effect of background knowledge was shown by manipulating the causal structure of prior knowledge provided to the subjects. It was found that later training instances affected the refinement of the background knowledge in different ways depending on the causal model initially given to the subjects. The two biases found in the current experiment are (1) knowledge refinement was conservative in the sense that background knowledge was modified as little as possible to account for the observed data and (2) weakening of an existing causal relationship resulted in automatic strengthening of a related causal relationship.