Linguistic intuitions are about communicativeness, not grammaticalness

People have spontaneous intuitions about the acceptability of sentences. "She gave me a book" is acceptable in English but "She gived I a book" is not. These intuitions are critical for the scientific study of language and cognition in many ways. They are widely assumed to be outputs of an intuitive sense of grammaticalness, and this assumption has provided the basis for many influential research programs, over many decades. Here I describe this assumption as illusory. Linguistic intuitions are better explained as byproduct effects of humans’ intuitive sense of communicativeness. Precisely, sentences are unacceptable when there appears to be an inherent impossibility of interpreting them in any way consistent with the unconscious presumption of communicative efficiency that governs the interpretation of all stimuli perceived as communicative. As such, linguistic intuitions parallel the intuitions that accompany ‘impossible objects’: visual illusions in which stimuli appear as objects but cannot be interpreted in any way consistent with the unconscious presumptions that govern the interpretation of all stimuli perceived as objects. The communicativeness approach accounts for signature features of linguistic intuition more parsimoniously than the grammaticalness approach. A single general principle may govern all linguistic intuition, but that general principle is about communicativeness, not grammaticalness.