Choose wisely when considering a partner, whether to attend church and how you look after your body. These decisions could have a significant effect on your overall life satisfaction. That’s according to a study that challenges the theory that life happiness is largely predetermined by your genes.

The widely accepted “set-point” theory of happiness says that an individual’s long-term happiness tends to be stable because it depends mainly on genetic factors. The idea is based in part on studies that show identical twins to have more similar levels of life satisfaction than non-identical twins, and suggests that although your level of happiness may occasionally be thrown off by major life events, it will always return to a set level within two years.

To find out whether people really are destined for a certain level of happiness, Bruce Headey at the University of Melbourne in Australia and his team questioned people in Germany about their jobs, lifestyles and social and religious activities. The survey was initially completed by 3000 people annually, but that rose to 60,000 per year by the end of the 25-year study period.

They found that certain changes in lifestyle led to significant long-term changes in reported life satisfaction, rather than causing the temporary deflections in happiness that set-point theory would suggest.


One of the biggest influences on a person’s happiness was their partner’s level of neuroticism. Those with partners who scored highly on tests for neuroticism were more likely to be unhappy – and to stay unhappy for as long as the relationship lasted.

Altruism and family values also influenced long-term happiness. People whose annual survey responses changed to place a higher priority on altruistic behaviours and family goals were rewarded with a long-term increase in life satisfaction. Those who prioritised career and material success, however, experienced a corresponding lasting decline.

Having strong religious commitments also seemed to help in the pursuit of happiness. “People who attend church regularly seem to be happier than people who are not religious,” says Headey.

A person’s weight turned out to be another factor for long-term happiness, especially for women. Underweight men scored slightly lower than those with healthy weights, while women reported being significantly less happy when they were obese. Being overweight appeared to have no effect on men’s happiness.

Robert Cummins at Deakin University in Burwood, Australia, notes that changes in happiness reported by Headey’s team could be influenced by individuals falling into or recovering from depression.

The group suggests its findings may be applied to other populations, having found similar patterns, as yet unpublished, in the UK and Australia.

Journal reference: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1008612107