Conventional metaphors elicit greater real-time engagement than literal paraphrases or concrete sentences

•Pupil dilation indexed greater focused attention on task (i.e., greater engagement).•Greater metaphoricity predicts fast, sustained dilation during auditory presentation.•60 sentence triples contain conventional metaphor, paraphrase, concrete description.•Stimuli normed on gradient metaphoricity and 7 other psycholinguistic factors.•Greater metaphoricity predicts likelihood that sentence conveys “richer meaning” Conventional metaphors (e.g.,a firm grasp on an idea) are extremely common. A possible explanation for their ubiquity is that they are more engaging, evoking more focused attention, than their literal paraphrases (e.g.,a good understanding of an idea). To evaluate whether, when, and why this may be true, we created a new database of 180 English sentences consisting of conventional metaphors, literal paraphrases, and concrete descriptions (e.g.,a firm grip on a doorknob). Extensive norming matched differencesacross sentence types in complexity, plausibility, emotional valence, intensity, and familiarity of the key phrases. Then, using pupillometry to study the time course of metaphor processing, we predicted that metaphors would elicit greaterevent-evoked pupil dilationcompared to other sentence types. Results confirmed the predicted increase beginning at the onset of the key phrase and lasting seconds beyond the end of the sentence. When metaphorical and literal sentences were compared directly in survey data, participants judged metaphorical sentences to convey “richer meaning,” but not more information. We conclude that conventional metaphors are more engaging than literal paraphrases or concrete sentences in a way that is irreducible to difficulty or ease, amount of information, short-term lexical access, or downstream inferences.