An explanation for teenagers' sulky outlook may have emerged from a study showing that adolescents suffer a form of brain regression at puberty.
Scientists have found young teenagers begin to lose the ability to discern important emotions in the faces of adults, causing them to behave temporarily like much youngerchildren.
Professor David Skuse of the Institute of Child Health in London said hormonal surges at puberty may cause a re-wiring of the brain of adolescents, which interferes with their ability to interact socially with their elders.
"There is a temporary deterioration in children's capacity to interpret accurately emotions from facial expressions. This may go some way to explaining the 'Kevin' phenomenon portrayed so perceptively by [comedian] Harry Enfield."
The scientists studied 600 children between the ages of 6 and 17 to see how good they were at recognising facial expressions.
In boys and girls there was a gradual improvement with age, which was interrupted only at puberty, when both sexes began to regress before recovering a few years later.
Pubescent children had difficulty understanding sadness and anger expressed in a face - more so even than in children three or four years younger.
"It appears that this is a function of the development of their brain at that time. It's a real biologically based phenomenon from which fortunately they recover.
"There is that age of around 12, 13 or 14 when they seem completely oblivious to nuances, not only of facial expressions - these same brain circuits are processing tone of voice."
