Moods spread like ripples through friends8217;

They ripple through networks 8220;like pebbles thrown into a pond8221;, the 8216;New Scientist8217; magazine8217;s online edition quoted lead researcher Nicholas Christakis of Harvard Medical School in Boston as saying.

Researchers came to the conclusion after analysing 53,228 social connections between 5,124 individuals over time. They found a happy friend increased the odds of someone being happy by 15 per cent 8212; but that a friend of a friend boosted the chance by about ten per cent, and a friend of a friend of a friend by about six per cent.

That was triple the two per cent chance of being happier caused by a 3,500 pounds pay rise. 8220;If you drop one pebble in a pond, it will create ripples out from the pebble. Most people will not be surprised that people with more friends are happier, but what really matters is whether those friends are happy,8221; Christakis said.

In fact, they also found that moods 8212; good and bad 8212; tended to travel more freely in same-sex groups, 8216;The Daily Telegraph8217; reported.

Despite physical proximity, the mood of a cohabiting partner was less than ten per cent likely to have an effect. Added co-researcher Prof James Fowler of California University: 8220;Each 8216;happy connection8217; increased the chance of a person8217;s happiness by nine per cent and each 8216;unhappy connection8217; decreased it by seven per cent.8221;