Environment can influence mood, but happiness has its roots in our genes

Published on Friday 29 February 2008 20:26

IS YOUR cup half-full or half-empty? Can you look on the bright side of life even when things aren't going your way?

Our general levels of happiness and satisfaction with life are partly determined by our personalities, and both personality and happiness are largely hereditary, according to a study published by Edinburgh University psychologists.

Scientists rate our personalities in terms of five "factors", or sets of characteristics. Dr Alex Weiss and his colleagues have found our propensity for happiness is linked with three of these: extraversion (outgoing, active); neuroticism (moody, nervous); and conscientiousness (forward thinking, decisive). So if you are an extrovert, conscientious and not neurotic, then you have a buffer against life's trials and tribulations.

"If you have that sort of personality profile you're more robust," says Weiss. "If you do encounter bad or unpleasant events, this would prevent your happiness from declining too much."

How did the researchers come to the conclusion that we inherit these propensities? In the study, published in Psychological Science, they scored 973 pairs of twins on personality traits and on their self-reported levels of happiness. The twins were divided into two groups: identical twins, who are genetic clones, and fraternal twins who are genetically no more similar than siblings. Within fraternal twins there was an association between happiness levels and personality traits, but these associations were much stronger in identical twins, suggesting a common genetic origin for personality and happiness.

So if happiness comes down to the genes we're born with, are we unable to increase our contentment through the way we live our lives? Weiss points out genes don't account for all the variation in personality and happiness. He says: "It's about 50 per cent heritable. There are independent effects of the environment on happiness, so the picture is not so bleak."

We all want to be happy because happiness feels great, but the effects do not end there. Happiness is linked with success in life domains including relationships and careers, and there is evidence it isn't simply that success makes us happy – positive moods and emotions can lead people to think, feel and act in ways that help them to achieve their goals.

Happiness brings health benefits too. Andrew Steptoe and his colleagues at University College London found in a study of 200 middle-aged Londoners that those who reported higher levels of happiness had fewer physical indicators of future diabetes, hypertension or cardiovascular problems.

Having a happy personality type would seem like good news then – but perhaps not entirely. Daniel Nettle, of Newcastle University, looked at the pros and cons of having an extrovert personality and while there are benefits, extroverts appear to be at greater risk of suffering accidents and ending up in hospital.

Given personality and happiness are highly dependent on genetics, could a bit of genetic tinkering make us happier? It's not that simple, says Weiss. Many genes are involved in personality and single genes could have multiple effects so it would be difficult to modify them in a predictable way.

"Hypothetically speaking, it's possible," he says. "Is it ever likely to be do-able? I don't think in my lifetime!"