Proceedings of the Annual Meeting of the Cognitive Science Society

Are simple explanations better? Research has shown that people favor simple explanations (defined as number of unex-plained causes; Lombrozo, 2007; Pacer & Lombrozo, 2017), but new findings suggest that under some conditions, com-plexity is preferred (Johnson et al., in press; Zemla et al., 2017). We explore three features that could affect preferences:causal structure, baserates, and likelihoods. Adults (N=544) read one simple and one complex explanation following oneof three causal structures. Simplicity preferences were strongest for one vs. two causes explaining two independent ef-fects, modest for one vs. two jointly sufficient causes explaining one effect, and reversed (to favor complexity) for one vs.two independently sufficient causes explaining one effect. When baserates and likelihoods were specified and matched,simplicity preferences were attenuated, while complexity preferences were sometimes reversed. These findings suggestthat simplicity preferences are moderated by several factors and point to a more unified account of explanatory reasoning.