A man and a woman chat.

She nods; he nods.

She rolls her eyes; he shakes his head.

She talks about her first-year daughter and smiles. He talks about his fourth-year son and winks.

She doesn’t know it, but he is really a she. And their conversation has more to do with body movements than gender.

That’s the conclusion of a team of psychologists and computer scientists led by UVA psychology professor Steven Boker. Using new videoconferencing technology, they were able to switch the perceived gender of participants during a conversation. By doing so, they found that people paid more attention to facial expressions and head movements than they did to the sex of their conversation partners.

“This is important because it indicates that how you appear is less important than how you move when it comes to what other people feel when they speak with you,” says Boker.

Participants conversed via computer screens. Some were talking with “avatars,” characters with synthesized faces and voices. The technology used statistical representations of a person’s face to track and reconstruct facial expressions and head movements in a connect-the-dots fashion.

“From a psychological standpoint, our interest is in how people interact and how they coordinate their facial expressions as they talk with one another,” Boker says. “When I coordinate my facial expressions or head movements with yours, I activate a system that helps me empathize with your feelings.”