· Feeling good 'is cause, not effect, of achievement' · Same principle applies to nations, academics claim

The recipe for success: get happy and you will get ahead in life

Happiness, rather than working hard, is the key to success, according to research published today. Cheerful people are more likely to try new things and challenge themselves, which reinforces positive emotion and leads to success in work, good relationships and strong health, say psychologists.

The findings suggest that happiness is not a "feelgood" luxury, but is essential to people's wellbeing. What is more, happiness can also extend across an entire nation, with people in "happy" nations being more likely to have pro-democratic attitudes and a keenness to help others.

The link between happiness and success was investigated by a team from the University of California Riverside, led by Professor Sonja Lyubomirsky.

First, they analysed questionnaires that ask people about multiple aspects of their lives. "For example, they show that happy people tend to earn higher incomes," said Prof Lyubomirsky. Having established the link, they wanted to discover the cause.

"Almost always it has been assumed that things that correlate with happiness are the causes of happiness, but it could be just the opposite - that those things tend to be caused by happiness," said Professor Ed Diener from the University of Illinois, another author on the paper.

Other studies revealed that having a sunny outlook on life appeared to precede good fortune.

"There was strong evidence that happiness leads people to be more sociable and more generous, more productive at work, to make more money, and to have stronger immune systems," said Prof Lyubomirsky.

Meanwhile, experimental studies showed that an instant injection of high-spirits could generate success. "Inducing a happy effect leads people to make more money in a computer simulation."

The research shows that while success can put a spring in someone's step, people need happiness in the first place to achieve success.

According to the study, around four out of five people in modern industrialised nations are happy at any one time.

Success was not just about earning lots of money. "We define success as obtaining the things that culture or society values, whether it be friends, close family, money and income, or longevity," said Prof Diener.

However, sorrowful people are not condemned to a life of failure.

"Our work suggests that sad people should try to increase the frequency of positive emotions in their lives by doing things that make them feel happy, even temporarily," said Prof Lyubomirsky, whose research is published in the Psychological Bulletin today.

But there is a caveat: your happiness boosters should not be dangerous, like driving fast, or counter-productive, like eating lots of chocolate.

If you can raise your spirits, the benefits can be manifold. "Happy people are more likeable and more sociable. They are also better able to cope with stress and likely to be healthier and live longer."

Nor is happiness just an individual pursuit. Happy nations, full of happy people, are more likely to be successful than unhappy nations. "People in happy nations trust others more and want to cooperate with their neighbours," said Prof Diener.

Governments could keep a smile on their citizens' faces by ensuring safety and stability.

"Although nations cannot live people's lives and force them to be happy, they can create conditions - for example, parks, reasonable weekly work hours, a health infrastructure, and good transportation - that influence people's happiness," he added.

For governments and individuals alike, it seems, happiness is more than just a hedonistic pleasure.