When a friend shares an embarrassing secret, you may try to hide your reaction with a poker face. But your head reveals the truth.
A recent study found that how people tilt their heads — either holding them high or casting eyes downward — conveys happiness and sadness, respectively, which people easily detect.
Steven Livingstone and his colleagues at the Sequence Production Lab at McGill University conducted two experiments to determine whether head movement betrays emotion. In the first, 12 adult singers, six male and six female, sang or spoke four neutral statements, such as “people going to the bank,” as either very happy, happy, neutral, sad or very sad.
The researchers used the same motion capture technology used in movies, such as "Avatar" or "Lord of the Rings", to record the head gestures. They found that people move their heads to express different emotions.
“The first experiment told us that a lot of people do this. But it doesn’t mean these head movements were useful,” said Livingstone, a postdoctoral fellow at McMaster University.
Both men and women move their heads the same — looking slightly upward to express happiness and gazing slightly downward to express sadness.
In the second experiment, one man and one woman from the first experiment spoke or sang neutral phrases as very happy, very sad, or neutral. The researchers edited the voices out and disguised the faces so that the 24 participants watching the video could only see how the heads moved. Participants had to determine whether the person in the video was expressing happiness, sadness or no emotion simply by looking at head movement. People accurately determined emotion without hearing tone of voice or seeing facial expressions.
“People were accurate at picking tone,” he said. “[Head movements] actually convey speakers’ emotion.”
Joe Navarro, a body language expert and author of the book What Every Body is Saying, who was not involved in the study, said that the findings show that nonverbal communication authentically communicates emotion.
Few people consider what the position of their head says so a head held high truly shows happiness— even if the person says otherwise.
“A head tilt is a very powerful communicator to the other party,” he said.
Livingstone says head movements match idioms people use to talk about happiness or sadness. Head held high or keep your head up expresses positive feelings, while being downcast implies sadness.
“People use these expression all the time and we talk about it … in literature about the relationship between head and emotions,” he said.
Both Navarro and Livingstone stress that these gestures might vary by culture—Navarro says younger people in Japan lower their heads when they meet with older people out of respect not sadness, for example.
Building a better robot
While Livingstone admits that more research needs to be done, he hopes that it might someday have clinical applications. He also thinks that understanding head movement in the nonverbal communication can help researchers build better humanoid robots.
But the findings show that nonverbal communication remains more complex than once thought.
“The fact that humans when they speak have these sort of head movements could provide a new piece of the puzzle,” he said.