Research from Mexico, Ghana, Sweden, USA and the UK shows that despite vastly different levels of wealth, citizens of these countries report similar levels of satisfaction. And most advanced nations have seen almost no change to individuals' happiness levels over the last 50 years, despite a huge hike in income.
This may be because people don't experience wealth without comparing it to others, says the author: "As we realise one set of aspirations, it seems we immediately trade up to a more expensive set, to which we transfer our hopes for happiness."
Happiness also affects health, as demonstrated in the former Soviet Union where people are "among the unhappiest in the world" and their life expectancy is dropping.
However, one can improve one's chance of happiness by being married, says the author. Married people live on average three years longer and have better health and wellbeing than the unmarried. Well developed family, social and community networks – "social capital" – also have a positive effect.
Work is key to individual satisfaction, adds the author. Scant control over workload or decision-making correlates with lower happiness levels. And "make sure you're not working so hard that you've no time left for personal relationships and leisure", says the author.
The happiness of its citizens should be the business of government, with ministers as answerable on happiness levels as they are on a nation's gross domestic product (GDP), he concludes.