Say cheese and be happy
NOT ONLY do smiles reflect happiness, they can even induce it, says psychologist Paul Ekman of the Human Interaction Lab at the University of California (Science, Vol 262, No 5132).
However, not any smile will do. In 1862, French neurologist Duchenne de Boulogne noted that half-hearted smiles only involve mouth muscles and that only smiles involving certain muscles around the eye are "put into play by the sweet emotions of the soul." Ekman and his colleague Richardson Davidson of the University of Wisconsin have shown that when a person deliberately activates one of those eye muscles, brain centres associated with enjoyment are also activated.