Proceedings of the Annual Meeting of the Cognitive Science Society

Philosophical accounts of health and disease typically assume that disease involves deviation from normality, but disagree on whether normality is descriptive (e.g., statistical frequency) or evaluative (e.g., harm). Recent experimental work suggests that ordinary judgments of normality integrate frequency and value, raising the question of whether disease concepts inherit this mixed structure. Across two preregistered vignette-based experiments, we tested how frequency, valence, and explicitly stated normality influence judgments of disease, dysfunction, and health in both somatic and mental domains. In Study 1, both frequency and valence affected disease judgments, but frequency effects disappeared when controlling for normality. In Study 2, explicit normality information strongly shaped disease, dysfunction, and health judgments, with substantially larger effects than frequency. These findings suggest that ordinary disease concepts rely on a mixed notion of normality.