Contagious yawn 'caused by empathy'
It is the plague of boardroom meetings, university lecture halls, and dentists’ waiting rooms everywhere – the contagious yawn.
Now scientists have discovered why the expression of tiredness spreads from person to person throughout a room and why young children are immune to it.
Workers who have the impulse to follow the yawns of their colleagues are simply trying to show empathy.
Rather than an embarrassment, the action should be seen as a sign that they more in touch with the feelings of others, the researchers said.
Contagious yawning among adults is epidemic, the report discovered, with more than 50pc regularly stretching their mouths at the sight of someone else doing the same.
Previous studies have suggested that yawning increases blood flow and oxygen levels in the brain, helping to maintain alertness and explaining why people often yawn when they are waiting for something stressful to happen, such as a visit to the dentist.
Evolutionary theorists have claimed that yawning is infectious because humans once lived together in groups and it was used either as a way to raise alertness levels in times of danger.
But scientists appeared to have confirmed the link between yawning and empathy by studying its prevalence amongst normally devloping children and children with autism spectrum disorder.
Children under the age of four and youngsters with autism do not suffer from infectious yawning because they do not experience the same levels of empathy, the report found.
Researchers from the University of Connecticut observed 120 well developing children between the ages of one and six.
The study showed that although babies yawn even before they leave the womb, the majority of children show no signs of succumbing to contagious yawning until they reach four years old.
In a second study they looked at 28 children between the ages of six and 15 with some form of autism.
Autism is a developmental disorder which affects children’s social interaction causing them to be unable to form normal emotional ties with people around them.
Scientists discovered that autistic children were less likely than typically developing children of the same age to yawn when someone else yawns.
The more severe a child’s autism the less likely he or she would yawn contagiously, the report published in the latest edition of the respected Child Development journal concluded.
The researchers said: “Given that contagious yawning may be a sign of empathy, this study suggests that empathy and the mimicry that may underlie it develop slowly over the first few years of life, and that children with autism spectrum disorders may miss subtle cues that tie them emotionally to others.”
Dr Catriona Morrison, a cognitive psychologist at the University of Leeds, said: “This kind of research highlights the fact that contagious yawning, which is a subconscious activity, is an indication of a high level of social evolution. It also fits in with the theory of mind that mental states develop as children get older.”