People often prefer simpler explanations because they havehigher prior probability. However, simpler explanations arenot always normatively superior because they often do notfit the data as well as complex explanations. How dopeople negotiate this trade-off between prior probability(favoring simplicity) and goodness-of-fit (favoringcomplexity)? Here, we argue that people use opponentheuristics—relying on simplicity as a cue to priorprobability but complexity as a cue to goodness-of-fit(Study 1). We also examine factors that lead one or theother heuristic to predominate in a given context. Study 2finds that people have a stronger simplicity preference indeterministic rather than stochastic contexts, while Study 3finds that people have a stronger simplicity preference forphysical rather than social causal systems. Together, weargue that these cues and contextual moderators act aspowerful constraints that help to specify otherwise ill-defined hypothesis comparison problems.
