Comparative illusions are evidence of rational inference in language comprehension

Sometimes sentences sound acceptable when they are ungrammatical or semanticallyimplausible. In this paper, we study “comparative illusion” (CI) sentences where people oftenrate a sentence like More people have been to Russia than I have to be acceptable while in factit is semantically anomalous. We provide a potential explanation for this language illusion fromthe noisy-channel framework. We hypothesize that comprehenders make rational inferencesover the perceived sentence by entertaining alternative “close” plausible interpretations, wherecloseness is determined by possible production errors. In four experiments, (1) we identified alinguistic construction that elicits a salient CI illusion effect; (2) we established a range ofplausible interpretations of the CI sentence; and (3) we found that the probability forcomprehenders to assign a certain plausible interpretation to the CI sentence is proportional tohow likely they think that that interpretation is to be produced as the CI sentence during noisylanguage communication.