(Agencies)
Updated: 2008-03-05 16:04

The key to happiness is not solely determined by your situation in life, but also by your genes, according to Australian researchers.

Psychologists at the University of Edinburgh and the Queensland Institute for Medical Research used a personality test called the Five-Factor Model on more than 990 twin pairs. Matching that with happiness data taken from the pairs, they found people who do not excessively worry, and who are sociable and conscientious tend to be happier.

The research, detailed in the March issue of the journal Psychological Science, identified evidence for common genes that result in the personality traits that predispose people to happiness, the researchers said.

"Although happiness is subject to a wide range of external influences we have found that there is a heritable component of happiness which can be entirely explained by genetic architecture of personality," said study team leader Alexander Weiss of the University of Edinburgh.

While these genes won't guarantee happiness, the personality mix they result in could act as a trigger when bad things happen, allowing people to have an "affective reserve" of happiness that can be called upon in stressful times.

And while the genetic influence is strong, about 50 percent of the differences in people's happiness in life can still be chalked up to a variety of external factors, such as relationships, health and careers.