Neurobiology of Language -
People tailor their hand gestures to the needs of their addressee
In a complex experimental paradigm, participants were asked to point at circles that were shown on a computer screen. They were instructed to point at a circle every time a circle would light up. They did this for an addressee, whose task was to write down which of the circles would light up. In one condition, participants pointed at circles that the addressee could see at the same time. Therefore the pointing gesture was not very informative. In another condition, they pointed at circles that the addressee could not see, making the gesture more informative for this other person in this latter case. The pointing participant was aware of whether the pointing gesture was more or less informative for the other person. Therefore, participants had different intentions depending on the state of knowledge of their addressee.
We found that when participants wanted to be more informative, so when their addressee could not see the circle light up, they slowed down their gesture and kept their finger in the endpoint location for a longer period of time than when they had to be less informative. At the same time, a P300 effect was found in their brain activity when comparing the two conditions, suggesting that participants paid more attention to their task when they needed to be more informative. Together, these findings show that everyday actions such as pointing at something for someone are shaped by the intentions that we have when performing the action.
Peeters, D., Chu, M., Holler, J., Hagoort, P., & Özyürek, A. (2015). Electrophysiological and kinematic correlates of communicative intent in the planning and production of pointing gestures and speech. Journal of Cognitive Neuroscience, 27(12), 2352-2368. doi:10.1162/jocn_a_00865.