Funny Business

Men's laughter changes according to how well they know their audience, while women laugh more in the presence of men.

Laughter is a subtle attempt to shape others' responses, according to Jo-Anne Bachorowski, Ph.D., an assistant professor of psychology at Vanderbilt University in Nashville, Tennessee.

Specifically, variations in laugh frequency and high-pitched "voiced" laughter, such as giggling or chuckling, aim to arouse. "Laughter is a nonconscious strategy of social influence," explains Bachorowski, who asked listeners to rate the attractiveness of recorded laughter. The results were published in Psychological Science.