Think about when you are most likely to yawn: maybe when bored in class, anxious about an exam, or getting ready for bed. However, odds are that you have an even higher chance of yawning right after you see someone else do so. This phenomenon is known as “contagious yawning,” and over fifty percent of adults have had it happen to them. By looking at candidate brain centers, scientists have attempted to identify the basis for this instinctive reaction to yawn when others do so. However, their efforts have largely been fruitless.
Research in evolutionary biology has done more to answer this question. A well-accepted theory now explains that the phenomenon of “contagious yawning” may be reliant on the capacity of the human brain to display empathy. Dr. Gordon Gallup, a University of Albany neuropsychologist, recently explained to the British Broadcasting Corporation that such yawning might be caused by, “empathic mechanisms which function to maintain group vigilance.” Basically, the theory is that when early humans saw others in their group yawn as they had just yawned themselves, it would increase group awareness that alertness levels were decreasing and thus, there was a greater threat to potential predators.
Your tendency to yawn after seeing someone else yawn is likely the product of a once-advantageous evolutionary adaptation. “Contagious yawning” may have helped early humans communicate with each other and coordinate their collective alertness and sleeping times. Therefore, the next time you yawn after seeing a friend do so, remember that this behavior once served your ancestors well. Just make sure that nothing is trying to eat you.