When Greta gets angry, Dave has noticed that she tends to be quiet, almost stoic. Greta can detect slight changes in Dave’s tone of voice that signal to her he is angry. Couples like us can learn to be extremely sensitive to signs of anger in their partners, because understanding your partner’s emotional state helps you decide how to respond.
It’s also important to be able to detect anger in strangers — in some cases, your very life might depend on it! Over the years, lots of research on anger has focused on facial expressions. While “anger” does have a characteristic facial expression that is readily detected, there’s plenty of other evidence we can use to decide if someone is angry, like Dave’s tone of voice and Greta’s silence. Until the past decade, however, very little research had been conducted on another important component of anger detection: Body position and movements.
Swann Pichon, Beatrice de Gelder, and Julie Grèzes sought to change that by undertaking one of the first systematic studies of brain response to angry body movements. They recorded video of 12 professional actors as they opened a door, reacted angrily to something they saw inside, and closed the door. The same actors were recorded performing the same action but responding neutrally. Then all the videos were edited to blur out the faces of the actors.
The researchers showed the videos to volunteers who were asked to say whether the person in each video was angry based only on body movements, selecting only the highest-rated videos to use during the brain scan portion of the study. A similar process was used to select a set of still images from the video.