Narrator: This is Science Today. Doctor Paul Ekman, a psychology professor at the University of California, San Francisco, has studied human facial expressions for over forty years. In the wake of the September eleventh attacks, he now finds himself informally applying his expertise to some national leaders, including Homeland Security Director Tom Ridge.
Ekman: Sometimes when I watch television, I see the kind of smile that Ridge shows when he talks about the latest threat or about the latest person who's gotten Anthrax, well then I'm looking very carefully to see what kind of smile is he showing?
Narrator: Ekman says what he sees are smiles that simultaneously convey gravity and reassurance - which can be a bit confusing.
Ekman: None of that's being deliberately deployed. Even these social smiles, these polite ones, the tactful ones, the agreement ones, we do those without thinking, they've become a habitual part of our conversational style. It's their absence that might worry us, not their presence.
Science Today, I'm Larissa Branin.