Study finds listeners use hand gestures to anticipate the next word in conversation

In face-to-face conversation, people do more than listen to speech: they also read the hands. New research suggests that listeners use meaningful hand gestures to predict which words a speaker is likely to say next, speeding up comprehension.

The work, led by scientists at the Max Planck Institute for Psycholinguistics and Radboud University in Nijmegen, tested whether gestures provide advance cues about upcoming speech. The team combined behavioural measures with electroencephalography, or EEG, to track how the brain responds.

Avatars reveal predictive listening

To tightly control timing and movement, the researchers used realistic virtual avatars that asked everyday questions. In one experiment, the avatar paused just before a key word, such as type, while making either a relevant typing gesture, a meaningless movement, or no movement at all.

Participants were asked to guess how the sentence would end before hearing the missing word. They predicted the target word more often when they saw the matching gesture, indicating that hand movements can guide expectations about what comes next.

EEG signals anticipation and easier processing

A second experiment examined brain activity while a different group simply listened to the full questions. During the silent pause before the target word, EEG patterns associated with anticipation differed depending on whether a meaningful gesture was present.

After the target word appeared, the brain showed a reduced N400 response when the gesture matched the word, a signal commonly linked to easier semantic processing. Together, the results suggest gestures help listeners prepare for upcoming meaning rather than merely adding emphasis after the fact.

Implications for robots and assistants

The findings also point to practical design choices for artificial agents, including robots and virtual assistants that use embodied avatars. If gestures can help humans predict speech in natural conversation, adding well-timed, meaningful hand movements could make synthetic communicators easier to understand.

Researchers say the broader takeaway is that language comprehension is inherently multimodal. Listeners do not wait passively for words to arrive, but actively integrate visual cues such as gestures to anticipate what a speaker is about to say.