Instead it found your choice of partner and life goals drastically affect your satisfaction with life – overturning the popular theory that happiness is largely decided by personality traits moulded early in life and genetic factors.

Up until now much research had seemed to show even extreme events such as becoming disabled or winning the lottery had little effect on people's happiness, and studies of twins strongly linked happiness to genetics.

But in reality, over the course of their life about 40 per cent of people experienced large changes in their levels of happiness, said the study leader, Bruce Headey, an associate professor at the Melbourne Institute at Melbourne University.

The study, the first to track happiness over a long period, followed 60,000 Germans for up to 25 years.

Over the long-term, happiness was variable, and depended on the life goals and choices of the individual.

People who prioritised their relationship with their partner and children were happier than those interested in career or material success, as were those with altruistic goals such as helping people or being involved in social or political activities.

Working shorter hours did not necessarily lead to happiness, but working a lot more or less than they wanted made people very unhappy.

“It appears that prioritising success and material goals is actually harmful to life satisfaction,” Professor Headey wrote in the journal Proceedings of the National Academy of Sciences.

Partner choice played a big role. Women were less happy if their partner did not prioritise family goals than if they had no partner, and people with a neurotic partner were far less happy over time. They never got used to their partner's negative emotions, either – even after 20 years of marriage there was no decline in the effects on their happiness.

Doing exercise and being a healthy weight were beneficial, and obesity was strongly linked to unhappiness, particularly for women.

Professor Headey did not know why many people continued to prioritise goals which did not seem to make them happy. "I think people don't often sit down and think about what really makes them happy, and then try to do more of that.”

RECIPE FOR CONTENTMENT

Have a happy partner

Don't be overworked or underworked

Prioritise family and community, and have a partner who does so as well

Don't be materialistic

Don't be obese