Proceedings of the Annual Meeting of the Cognitive Science Society

A common intuition, often captured in fiction, is that some impossible events (e.g., levitating a stone) are “more impossible” than others (e.g., levitating a feather). We investigated the source of this intuition, hypothesizing that graded notions of impossibility arise from explanatory considerations logically precluded by the violation at hand but still taken into account. Studies 1-2 involved college undergraduates (n = 192), and Study 3 involved preschool-aged children (n = 32). In Study 1, participants saw pairs of magical events (spells) that violated one of 18 causal principles—six physical, six biological, and six psychological—and were asked to indicate which spell would be more difficult to learn. Both spells violated the same causal principle but differed in their relation to a subsidiary principle. Participants’ judgments of spell difficulty honored the subsidiary principle, even when participants were given the option of judging the two spells equally difficult. Study 2 replicated the effects of Study 1 with Likert-type ratings, and Study 3 replicated those effects in children. Taken together, these findings suggest that events that defy causal explanation are interpreted in terms of explanatory considerations that hold in the absence of such violations.