Proceedings of the Annual Meeting of the Cognitive Science Society

Why do people gesture when they speak? According to one influential proposal, the Lexical Retrieval Hypothesis (LRH), gestures facilitate speech production by helping people find the right spatial words. Do gestures also help speakers find the right words when they talk about abstract concepts that are spatialized metaphorically? If so, gesture prevention should increase disfluencies during speech about both literal and metaphorical space. We sought to conceptually replicate the finding that gesture prevention increases disfluencies in speech about literal space, which has been interpreted as evidence for the LRH, and to extend this pattern to speech about metaphorical space. Our large dataset provided no evidence that gestures facilitate speech production, even for speech about literal space. Upon reexamining past research, we conclude that there is, in fact, no reliable evidence that preventing gestures makes speech more disfluent. These findings challenge long-held beliefs about why people gesture when they speak.