The moment when dad gets up to strut his stuff on the dancefloor is a toe-curling ordeal familiar to every teenager. While mothers and fathers take pride in watching their adolescent offspring sing, dance or perform, it is a source of acute embarrassment when the roles are reversed.

An explanation has now been advanced by scientists. The adolescent brain seems to process the emotions of embarrassment and guilt differently from those of adults. The first brain-scan study to investigate the issue, conducted at University College London, identified clear differences in brain activity when teenagers and adults were asked to think about social emotions.

While both teens and adults use the same parts of the brain when processing emotions such as disgust and fear, which do not involve the opinions of other people, their scans show pronounced contrasts when they think about embarrassment or guilt.

Adolescents engage a particular part of the brain called the medial prefrontal cortex when considering these feelings, while adults do not, according to the study, led by Stephanie Burnett and Sarah-Jayne Blakemore.

The findings, which are published in the Journal of Cognitive Neuroscience, offer a potential explanation for the way children who, when younger, would have revelled in exuberant parental behaviour start to blush at it after puberty.

In the long term, they could shed light on conditions such as eating disorders and anxiety, which become more common after puberty and are affected by people’s self-image. “It is well-known anecdotally that teenagers are particularly susceptible to embarrassment caused by family and parents, and they’re much more embarrassed in front of friends than strangers,” Dr Blakemore said. “Studies by social psychologists confirm this. One of the best ways of illustrating it is an anecdote told by one of my friends who has teenage daughters. Before they reached puberty, if they were messing around in a shop, he’d get them to stop by promising to sing their favourite song. After puberty, he’d get them to stop by threatening to sing their favourite song.”

The differences in activity in the medial prefrontal cortex, which is involved in processing social emotions and planning, might explain this. “If teenagers have more activity in this part of the brain when they are thinking about being embarrassed, it might explain why they are more susceptible to embarrassment,” Dr Blakemore said. She added that it remained uncertain whether the brain activity was a cause or an effect of heightened sensitivity to embarrassment.

In the study, the scientists recruited 19 girls aged between 10 and 19 and ten adult women, aged between 22 and 32. All the subjects then had their brains scanned, using functional magnetic resonance imaging (fMRI), while they were asked to imagine a string of emotional experiences.

Examples designed to evoke embarrassment included thinking about your father dancing in the supermarket, and dribbling food down your top while eating with a friend.

Other thoughts were designed to invoke guilt, and disgust and fear were used as controls because they are not dependent on the particular reactions of onlookers.

Dr Blakemore said the research could eventually have implications for medical conditions and for education. Anorexia and bulimia, she said, were “among the reasons why people are doing this research. Anxiety, depression and eating disorders all increase hugely in prevalence after puberty.”

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