Generic priors yield competition between independently-occurring causes
Powell, D., Merrick, A., Lu, H., & Holyoak, K. J. (2013). Generic priors yield competition between independently-occurring causes. Proceedings of the 35th Annual Conference of the Cognitive Science Society. Austin, TX: Cognitive Science Society.
Abstract
Recent work on causal learning has investigated the possible role of generic priors in guiding human judgments of causal strength. One proposal has been that people have a preference for causes that are sparse and strong—i.e., few in number and individually strong (Lu et al., 2008). Evidence for the use of sparse-and-strong priors has been obtained using a maximally simple causal set-up (a single candidate cause plus unobserved background causes). Here we examine the possible impact of generic priors in more complex, multi- causal set-ups. Sparse-and-strong priors predict that competition can be observed between candidate causes even if they occur independently (i.e., the estimated strength of cause A will be lower if the strength of uncorrelated cause B is high rather than low). Experiment 1 revealed such a cue competition effect in judgments of causal strength. Experiment 2 showed that, as predicted by a Bayesian learning model with sparse-and-strong priors, the impact of the prior diminishes as sample size increases. These findings support the importance of a preference for parsimony as a constraint on causal learning.