Teenage angst and clashes with authority may be caused by changes in youngsters brains during puberty, but luckily for harassed parents the problems pass.

The ability of boys and girls to decode social cues and recognize emotions, particularly anger and sadness, dips between the ages of 12 and 14, researchers at University College London and the Institute of Child Health have discovered.

It would appear that this is a function of the development of their brain at that time,Professor David Skuse, of the groups behavioral science unit, told at a recent conference.

It is a real biologically based phenomenon from which, fortunately, they recover, he added.

So rather than rebellious teenagers being deliberately obstinate or difficult, their brains may be unable to detect subtle signs from parents, teachers and other adults or to decode them correctly.

The same brain circuits involved in recognizing facial expression are also associated with processing tone of voice, according to Skuse.

The ability to interpret your irritated tone of voice, the ability to interpret your angry facial expression may well deteriorate during that period of early adolescence, he added.

But the problem seems to disappear by the age of 16 or 17.

Research into autism
Skuse, who presented the findings at the British Association for the Advancement of Science conference in the Irish capital, found the dip during puberty while studying 6,000 children as part of his research into autism, a condition that affects far more boys than girls.

All of the children, aged 6-16, were asked to do certain tasks such as remembering faces, establishing eye contact and distinguishing emotions by looking at photographs of faces which depicted happiness, sadness, anger, fear, surprise and disgust.

All those are abilities related to our capacity to interact appropriately with other people socially and are abilities that are supposedly deficient in people who are autistic, Skuse explained.

He and his colleagues found that at the age of six girls were better than boys in interpreting emotions and social cues. But by puberty, when the body is going through hormonal changes, there was a drop in the ability of both sexes to perform the tasks.

It looks as though when the brain reorganizes itself during puberty, rewires itself as a consequence of the hormonal changes presumably taking place at that time...we actually get worse at recognizing facial expressions and remembering faces we have seen before than we were 5 years previously, said Skuse.