Babies who are born to gamble

Research suggests our urge to take risks may depend on when we celebrate our birthday. Patricia Reichardt reports

Nick Leeson will forever be known as the man who gambled away an entire bank. The rogue trader, whose doomed fraudulent attempt to cover his £850m losses on the Singapore markets brought down Barings and earned him six years in jail, maintained he was simply trying to recover his employers' losses without ever being found out.

Nick Leeson will forever be known as the man who gambled away an entire bank. The rogue trader, whose doomed fraudulent attempt to cover his £850m losses on the Singapore markets brought down Barings and earned him six years in jail, maintained he was simply trying to recover his employers' losses without ever being found out.

Some commentators suggested such a large-scale fraud was the inevitable result of desperate traders operating under such high pressure. But new research suggests there's a simpler explanation for Leeson's urge to gamble. He was born in February.

A paper by Carol Joinson and Daniel Nettle at the Open University has, they say, proved a link between the season in which a person is born and the likelihood they will take risks. Their study reveals individuals born between October and March to have a significantly higher level of "sensation seeking" than people whose birthdays are in the spring or summer.

A quick trawl of well-known risk-takers seems at first glance to back this up. Formula One world champion Michael Schumacher was born on 3 January and the man regarded as the world's greatest ever racing driver, the late Ayrton Senna, on 21 March. Tragic water speed record-holder Donald Campbell was also a winter baby, as was Antarctic explorer Ernest Shackleton, first man in space Yuri Gagarin and gangland boss Al Capone.

This is certainly not the first study to link particular traits with seasons of birth. Previous research has suggested the month in which a person is born can make him or her more prone to autism, depression, dyslexia and schizophrenia. It can even increase the chances of being left-handed.

But why should this be? "There could be several factors," said Dr Joinson of the Open University's department of Biological Sciences, whose research was funded by the Leverhulme Trust. "Characteristics could be shaped by, say, social surroundings, or temperature, or nutrition, or whether a mother is prone to infection, but certainly one credible cause is the turnover of dopamine in the brain."

The chemical, which produces sensations of pleasure and carries messages between the brain cells, is already known to be associated with certain conditions - an excess may result in schizophrenia and a paucity can contribute to Parkinson's disease. And interestingly, dopamine levels have been shown to be higher in individuals born in winter.

"This has been suggested to be due to the length of photoperiod - the amount of light in a 24-hour period - during gestation or early neonatal development," says Dr Joinson. "The link may even go back to the moment of conception."

Almost 450 Open University students responded to an invitation to fill in a questionnaire, which asked participants to examine 40 pairs of statements and state which of each pair best described them. The questionnaire, developed 10 years ago by American Professor Marvin Zuckerman, covered a variety of subjects including drug-taking, sexual inhibition, mountain-climbing and parachute-jumping, as well as more oblique references to looking at other people's holiday snaps, making friends with gay people and attitudes to modern art.

"Risk-taking can take many forms, depending on many social and economic factors," says Dr Joinson. "It could be skiing down a mountain, or it could be going to the pub and getting drunk. But it's all risk-taking and Zuckerman's questionnaire is widely accepted as one of the most appropriate methods to measure it."

The survey showed that participants between the ages of 20 and 45 years who were born during October to March were more likely to engage in sensation-seeking behaviours than people of the same age born during April to September. "Sensation seeking" is defined in earlier research by Zuckerman as "the seeking of varied, novel and intense sensations and experiences and the willingness to take physical, social, legal and financial risks for the sake of such experiences."

But just as fascinating is the researchers' finding that winter babies aged between 46 and 69 years were considerably less likely to take risks than their summer counterparts.

"Of course we would expect younger people to take more risks," says Dr Joinson. "For most people youth is all about trying new experiences - leaving home, going out into the world, getting their first job etc. And most people, through life experience, do tend to take fewer risks as they get older. What is significant about these results is that later on in life the level of risk-taking among people born in winter declines to a level below that of people born in summer."

The lack of humans' willingness to gamble in later life is born out by numerous studies which show the brain's level of dopamine starts to decrease from the age of 40. But this decline still doesn't clearly explain why the level of risk-taking among those born in the winter should fall so steeply.

"It's been suggested that there is a link with the length of photoperiod when people are born and what this means in terms of dopamine turnover across the entire lifespan," says Dr Joinson, who is now understandably keen to undertake more research in the southern hemisphere and on the equator to see if results there correlate with her recent findings.

"It does seem to be the case that the season in which you're born can have far-reaching effects for the rest of your life."

And not, of course, just yours. If you're born to be a stock-market trader, it may have quite an effect on other people's, too.