Proceedings of the Annual Meeting of the Cognitive Science Society

People are more likely to gesture when their speech is disfluent. Why? According to an influential answer to this question, people gesture when they are disfluent because gestures facilitate speech production (Krauss & Hadar, 1999). Here, we propose an alternative explanation: People may gesture when their speech is less fluent because gestures serve as a pragmatic signal by commenting on problems with speaking. If so, when the listener cannot see the speaker, the speaker’s pragmatic motivation to gesture more during disfluencies should disappear. As predicted, we showed that people were more likely to gesture when their speech is disfluent only when the listener can see their gestures, but not when the listener cannot see their gestures. These results suggest that people gesture more when speaking is difficult, not because gestures facilitate speech, but rather because gestures comment on speakers’ difficulty with presenting an utterance for the listener.