‘Women, as a rule, smile more than men, but the difference between the sexes disappears depending on the circumstances.

For women, smiling is the default option. For men, the default is not smiling.

“If you don’t know what to do and you’re a female you smile because you know you’re not making a mistake. If you’re a man, you don’t smile,” says Marianne LaFrance, a psychology professor at Yale University.

In the largest analysis of smile studies ever done, LaFrance and her colleagues evaluated research involving nearly 110,000 people, finding many variations in smiling behavior.’