A healthy nation laughs. This benefits psychological health and decreases pain. For example, for a Brit, there's nothing more funny than a gross insult or what many in other parts of the world consider wholly inappropriate: war, sex, race, death. On the other hand, for others, watching "Friends" requires a deep concentration for understanding the jokes, so that they would laugh. Or a psychologist to explain the scenes.

In the end, if All Bundy or Austin Powers makes you laugh, it is both a question of genes and learning, as revealed by a new research led by Dr. Rod Martin, a psychologist at the University of Western Ontario, in Canada.

"It is possible that differences exist between nations in their sense of humor and that these may be the results of different genetic and environmental differences. The British may have a greater tolerance for a wide range of expressions of humor, including what many Americans might consider aggressively sarcastic or denigrating, like in Fawlty Towers and Blackadder. In the North American version of The Office, the lead character is much less insensitive and intolerant than in the original UK version," said Martin.

His team studied 2,000 pairs of British twins and 500 pairs of American twins. The research also found that TV humor in Britain was more biting, whereas in the U.S. it tended to be "softer."

"Positive humor," looking at the bright side of life, was common in both British and American twins. But "negative humor," going from gentle racist teasing to sexist humiliation, was enjoyed only by the British twins. It appeared that it was rather "learnt" than it was innate behavior.

"What the Americans don't understand is the British desire to keep putting themselves down - but they fully understand irony. Their humor is considerably more sophisticated than British humor. Look at their sitcoms - the level of wit and sophistication in Friends - we don't have anything to match that. Ours tend to be about silly people doing silly things whereas in America it's clever people doing clever things," British comedian Charlie Higson told Telegraph.co.uk.