The old saying goes, “Yawns are contagious,” but have you considered the biology behind it? While previous studies have suggested a connection between contagious yawning and empathy, new research from the Duke Center for Human Genome Variation finds that contagious yawning may decrease with age and is not strongly related to variables like empathy, tiredness, and energy levels. The study, published in the scientific journal PLOS ONE, is the most comprehensive look at factors influencing contagious yawning to date.
Contagious yawning is a well-documented phenomenon that occurs only in humans and chimpanzees in response to hearing, seeing, or thinking about yawning. It differs from spontaneous yawning, which occurs when someone is bored or tired. Spontaneous yawning is first observed in the womb, while contagious yawning does not begin until early childhood.
The researchers said a better understanding of the biology involved in contagious yawning could ultimately shed light on illnesses such as schizophrenia or autism. People with these disorders, both of which involve impaired social skills, demonstrate less contagious yawning despite still yawning spontaneously. “It is possible that if we find a genetic variant that makes people less likely to have contagious yawns, we might see that variant or variants of the same gene also associated with schizophrenia or autism,” said study author Elizabeth Cirulli Ph.D. ’12, assistant professor of medicine at the Center for Human Genome Variation at the School of Medicine. “Even if no association with a disease is found, a better understanding of the biology behind contagious yawning can inform us about the pathways involved in these conditions.”