奇速英语

科学探索传染性哈欠背后的真相

Every person yawns. While yawning is contagious (有感染力的), not everyone catches a yawn. Around 60-70% of people yawn if they see another person yawn in real life or in a photo or even read about yawning. Scientists have proposed many theories for why we catch yawns.

Catching a yawn shows you are attuned to a person’s emotions. Scientific evidence comes from a 2010 study at the University of Connecticut, which concluded yawning does not become contagious until a child is about four years old, when empathy skills develop. In the study, children with autism (孤独症), who may have impaired empathy development, caught yawns less often than their peers. A 2015 study addressed contagious yawning in adults. In this study, college students were given personality tests and asked to view video clips of faces, which included yawning. The results indicated students with lower empathy were less likely to catch yawns.

However, the link between yawning and empathy is inconclusive. In the Research at the Duke Center for Human Genome Variation, 328 healthy volunteers watched a video of people yawning and counted how many times they yawned while watching it. While most people yawned, not everyone did. Of the 328 participants, 222 yawned at least once. Repeating the video test multiple times revealed no obvious connection between empathy, time of day, or intelligence and contagious yawning, yet there was a statistical correlation between age and yawning. Older participants were less likely to yawn. However, age-related yawning only accounted for 8% of the responses.

Scientists aren’t completely certain why contagious yawning occurs. It has been linked to empathy, age, and temperature, yet the underlying reason why isn’t well understood. Not everyone catches yawns. Those who don’t may simply be young, old, or genetically related to not-yawning, not necessarily lacking empathy.