Do gestures really facilitate speech production?

Why do people gesture when they speak? According to one influential proposal, the Lexical Retrieval Hypothesis (LRH), gestures serve a cognitive function in speakers' minds by helping them 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, then preventing people from gesturing should increase the rate of disfluencies during speech about both literal and metaphorical space. Here, we sought to conceptually replicate the finding that preventing speakers from gesturing increases disfluencies in speech with literal spatial content (e.g., the rocket went up), which has been interpreted as evidence for the LRH, and to extend this pattern to speech with metaphorical spatial content (e.g., my grades went up). Across three measures of speech disfluency (disfluency rate, speech rate, and rate of nonjuncture filled pauses), we found no difference in disfluency between speakers who were allowed to gesture freely and speakers who were not allowed to gesture, for any category of speech (literal spatial content, metaphorical spatial content, and no spatial content). This large dataset (7,969 phrases containing 2,075 disfluencies) provided no support for the idea that gestures help speakers find the right words, even for speech with literal spatial content. Upon reexamining studies cited as evidence for the LRH and related proposals over the past 5 decades, we conclude that there is, in fact, no reliable evidence that preventing gestures impairs speaking. Together, these findings challenge long-held beliefs about why people gesture when they speak. (PsycInfo Database Record (c) 2022 APA, all rights reserved).