They’re All Like That! The Universality Signature of Central Form

This paper investigates how humans store information within the thousands of concepts that structure thought, belief, and action. Building on recent work suggesting that each concept has a central form—a core representational structure that triggers strong beliefs when properties are encoded into it—this paper introduces and tests a new form-triggered belief: a default universality belief. Across two experiments, participants judged central form properties as universally true of all category members. They rejected this belief for properties that were highly prototypical or causally important, if they were not part of the concept's form. This effect held across both familiar and novel categories, and across domains including animals, artifacts, institutions, places, and events. These findings suggest a domain-general mechanism underlying universality judgments, with implications for theories of stereotyping, trauma, and ideology. More broadly, they help to explain how humans construct complex thoughts by reducing complex concepts down to a limited set of core properties, and they resolve a longstanding puzzle about why people assume universality despite its rarity in the natural world.