An explanatory heuristic gives rise to the belief that words are well suited for their referents

•The words of a language are arbitrary social conventions.•Yet, children—and even adults—seem to believe words “fit” with their referents.•We propose that this belief arises from a reliance on heuristic explanations.•Six studies with children and adults (N=1062) provided support for this proposal.•The findings suggest heuristic influences on people’s reasoning about language.