Experts have recently published research in the academic journal Current Biology that suggests “contagious yawning” is triggered automatically by an area of the brain responsible for motor function. Even if we aren’t feeling tired, we are apt yawn if someone else does. All vertebrae animals do this too.
Researchers at the University of Nottingham have found in their latest research into this subject that our ability urge to yawn is increased if we are instructed to resist yawning. When we try to stifle a yawn, it changes how we yawn, but we are still likely to yawn. The degree to which this “sympathetic” response to others’ yawns appears to vary from individual.
Yawning is a reflex all of us have from birth to adulthood. There are multiple theories about why we have this reflex. One theory is that when we are bored or tired, we just don’t breathe as deeply as we usually do because our breathing has slowed. Yawning helps us bring more oxygen into the bloodstream and carry more carbon dioxide out. The yawning stretches the lungs, increasing airflow and heart rate.
Researchers a few years back found that people yawn more in cold climates. Could this mean the reflex is an adaptation to use cold air as a means to increase alertness?
Others theorize that contagious yawning is social adaptation. Across cultures and species, contagious yawning could be an automatic signal when bored that spreads agreement throughout the group (or pack) that they can relax. They are not under threat or attack.
“A of these theories sound likely to me,” says Dr. Jamie A. Alexander, Boynton Beach, Florida’s cosmetic and restorative dentist. “You show your teeth when you smile, and you show the tops of your lower teeth when you yawn. We yawn so frequently, that many baby boomers with older silver amalgam fillings want them replaced with tooth-colored fillings. Along with teeth whitening, tooth colored fillings are among the most sought after cosmetic changes adults request. If you would like to have your teeth appear naturally beautiful and ageless when you yawn, that’s where I come in as your dentist—I can help!”