Studies have shown people in Denmark rank as the happiest people on Earth, and scientists now say a new study suggests that happiness could have a genetic basis.
Data from quality of life surveys from 131 countries implies that the closer people in any nation are to Danes -- genetically, that is -- the happier they are likely to be, researchers at Britain's University of Warwick say.
"The results were surprising; we found that the greater a nation's genetic distance from Denmark, the lower the reported wellbeing of that nation," researcher Eugenio Proto says.
The link held even after the data was adjusted for other influences such as culture, religion, geography, Gross Domestic Product and the potency of the welfare state, he says.
Previous research has suggested mental wellbeing is associated with a mutation in the gene controlling brain levels serotonin, a chemical linked to moods.
Long versus short variants have been linked to possibilities of clinical depression and unhappiness, although the researchers acknowledge the existence of a link is the subject of much debate.
"The short version has been associated with higher scores on neuroticism and lower life satisfaction," Proto says. "Intriguingly, among the 30 nations included in the study, it is Denmark and the Netherlands that appear to have the lowest percentage of people with this short version."
The possible link between human happiness and genetics was found to hold true even across generations and continents, the researchers said.
The examined levels of wellbeing reported by Americans and then correlated that with what part of the world their ancestors had arrived from.
"The evidence revealed that there is an unexplained positive correlation between the happiness today of some nations and the observed happiness of Americans whose ancestors came from these nations, even after controlling for personal income and religion," Warwick co-researcher Andrew Oswald says.
He suggested more research similar to the Warwick study, conducted by the university's Center for Competitive Advantage in the Global Economy, is needed and that social scientists and economists might consider giving greater attention to the role of genetic variations among national populations.
"Contrary to our own assumptions when we began the project, it seems there are reasons to believe that genetic patterns may help researchers to understand international well-being levels," Oswald says.
The Warwick study -- "National Happiness and Genetic Distance: A Cautious Exploration" -- has been published by the Institute for the Study of Labor, based in Bonn, Germany, which specializes in research in various fields of economics.