PARSIMONY IN INTUITIVE EXPLANATIONS FOR BEHAVIOR - RECONCILING THE DISCOUNTING PRINCIPLE AND PREFERENCE FOR CONJUNCTIVE EXPLANATIONS

How do people judge how much explanation a behavior requires ? Attribu tion researchers have identified two pertinent phenomena: the discount ing effect, in which participants attribute less to one cause of a beh avior when informed of the presence of a strong alternative cause, and the conjunction effect, in which participants deem an explanation wit h two causes as more likely than an explanation with only one of these causes. Several researchers have asserted that these two effects refl ect contrary modes of explanation and, consequently, that findings of widespread conjunction effects in explanation are grounds for doubting the layperson's concern for parsimony that Kelley's discounting princ iple implies. By contrast, we propose that discounting and conjunction effects reflect a common process of parsimonious reasoning from share d causal schemas. Experiment 1 tests our proposal concerning how these processes co-occur. Experiments 2 and 3 test unique predictions from our model about moderators of the two effects.