‘It is fascinating how quickly people can react to each other’, the neuroscientist explains. ‘If you show people a picture of a mobile phone, for example, it can take up to 600 milliseconds before they say “mobile”. But people can respond to a question asked by another person within 200 milliseconds’. Ter Bekke wanted to investigate the role of the body in these rapid reactions.
Pedalling motions
Her research shows that people respond more quickly to a question if they see a hand gesture. To this end, she analysed hours of video material in which 34 pairs of friends were talking to each other. ‘Every time someone asked a question, I looked to see if there was a hand gesture and how quickly the other person responded to it. The analysis showed that hand gestures do indeed help people respond more quickly.’ A subsequent experiment in which participants watched a video of an actress asking questions with or without hand gestures confirmed this. For example, the question of whether there are more bicycles in the Netherlands than in other countries was answered more quickly when the actress made pedalling movements with her two fists.
Types
The next question was how this is possible. After conducting new experiments, Ter Bekke concluded that hand gestures may cause faster responses because they can be used to predict what someone is going to say. ‘If listeners hear, for example, “How old were you when you learned...”, and they see the speaker making a hand gesture as if they were typing, they can already predict how the question will continue. We also saw in the brain that listeners use such hand gestures to predict what someone is going to say.' These predictions allow listeners to start preparing their answer earlier and thus respond more quickly: it turned out that the better a hand gesture predicts what someone is going to say, the more it helps with responding quickly to questions.
After years of only looking at hand gestures, the neuroscientist recognises their importance. ‘If you want a quick answer to your question, add a hand gesture. If you want to convey an important message clearly, don't make a phone call, but try to make an appointment or video call – and in the latter case, make sure your hands are clearly visible, as this will help you understand each other much better.'