The Feb. 27 issue of the New Yorker has a review by John Lanchester of several books on happiness. Jonathan Haidt, "The Happiness Hypothesis"; Darrin McMahon, "Happiness, a history"; Richard Layard, "Happiness: Lessons from a New Science".
A first point is that we are hardwired to emphasize the negative, because being cautious and apprehensive makes us more likely to pass on our genes than being open, risk-taking, and happy. "Responses to threats and unpleasantness are faster, stronger, and harder to inhibit than responses to opportunities and pleasures." But, "are we, left to our own devices, and provided with sufficient food and freedom and control over our circumstances, naturally happy?" It depends on circumstances. People living in poverty become happier if they become richer, but the effect of increased wealth cuts off at a surprisingly low figure. Americans are twice as rich as they were in the 1970's but report not being any happier. Data from all over the world show that people get stuck on a "hedonic treadmill": their expectations rise at the same pace as their incomes, and the happiness they seek remains constantly just out of reach.
There is considerable evidence (from identical twin and other studies) that we each have a natural "set point" level of happiness that is largely inherited. In the long run, it doesn't much matter what happens to you. Whether you win the lottery or break your neck, within a year you feel pretty much the same as you did before.
Positive psychologists, however, argue that there are conditions most likely to generate contentment or happiness. Csikzentmihalyi's studies show that people are more content when are are experiencing what he calls "flow", a state ot total immersion in a task that is challenging yet closely matched to one's abilities." In this view, happiness is a by-product of absorption. The trouble is that asking yourself about your frame of mind is a sure way to lose your flow. If you want to be happy, don't ever ask yourself if you are.