Strange it may appear, but a Facebook-like feature in your brain rules your social network, say researchers.

A new study has found that amygdala, a small almond- shaped structure, deep in the temporal lobe governs the number of friends one is likely to make -- the larger the amygdala, the wider and more complex is its owner's network of pals.

For the study, the researchers asked volunteers aged between 19 to 83 to complete questionnaires which measured how many regular social contacts they had and in how many groups.

Magnetic resonance imaging scans found a positive link between big amygdalas and the richest social lives, the 'Daily Mail' reported.

Lead researcher Professor Lisa Barrett, a psychologist at Northeastern University in Boston, Massachusetts, said that the findings were consistent with "social brain" theory, which suggests human amygdala evolved to deal with an increasingly complex social world.

Other studies of primates have shown that those living in larger groups tend to have larger amygdalas. .

Dr Lisa Barrett, Professor of Psychology at Northeastern University, who took part in the study, published in the 'Nature Neuroscience' journal, said that the amygdala got bigger to cope with mankind's more hectic social life.

She added: "Further research is in progress to try to understand more about how the amygdala and other brain regions are involved in social behaviour in humans."

Another researcher Dr Bradford Dickerson of Harvard Medical School added: "This link between amygdala size and social network size and complexity was observed for both older and younger individuals and for both men and women."

Recently US scientists reported on the case of a woman whose amygdala had been destroyed by a medical condition.

As a result, the 44-year-old mother of three felt no fear and constantly put herself in danger. Over the years she had been threatened with a knife, held at gunpoint and also assaulted.