The findings from the University College London could perhaps help explain why seemingly respectable adults sometimes just can't resist throwing a tantrum or sulking until they get their own way.

The discovery that the part of the brain key to getting on with others takes decades to fully form could perhaps also explain why some people are socially awkward well past their teenage years, reports the Daily Mail.

Neuroscientist Sarah-Jayne Blakemore of University College, said: "Until about 10 years ago, it was pretty much assumed that the human brain stops developing in early childhood.

"But we now know that is far from the truth. In fact, most regions of the human brain continue to develop for many decades," Blakemore said.

"The region that goes through the most protracted development is the pre-frontal cortex at the front of the brain.

"It is involved in decision-making, planning and inhibiting inappropriate social behaviour and also things like social awareness and understanding other people and empathy," said Blakemore.