When physicist Paul Rothemund of the California Institute of Technology created smiley faces by the billion out of self-assembling pieces of DNA (Nature 440, 297–302; 2006) — an achievement celebrated on the cover of this journal — it gave his friend and colleague Erik Winfree a nice opportunity to joke that the work represented “the most concentrated happiness ever created”. But in general, although happiness may often be a by-product of scientific research — most notably for the researchers themselves — its direct production, let alone its concentration, is not.

Yet happiness is not a purely subjective phenomenon, immune to scientific analysis. As we report on page 418, it is a focus of interest on the parts of both researchers and policy-makers. A growing number of people are calling for happiness, and measures to enhance it, to be given greater weight in government policy. Richard Layard of the London School of Economics and Political Science, who also has a seat in Britain's House of Lords, explicitly points to what he sees as a “new science” of happiness as the basis for promoting radical shifts in political goals.

Unfortunately, this new science has yet to provide a compelling account of how happiness is created. Instead, for obvious methodological reasons, it concentrates on what it correlates with. But it is not clear that changing those correlates by dictat would necessarily produce the desired effect. People may be happy spending time with their children, but forcing parents to spend more time this way would not necessarily overjoy everyone involved. Expressing gratitude makes people happier; a politeness police, probably, would not.

There is further debate as to whether trying to do something about people's happiness is feasible in principle. Some researchers favour the idea that people have a 'hedonic setpoint' that stays remarkably constant in the face of bouquets and brickbats. Such a setpoint need not in principle be unalterable, but its alteration might require an approach with a pharmacological component, raising the problem that one of the things we value about happiness is its authenticity. Another is its autonomy. Governments may guarantee citizens freedom in their pursuit of happiness, but we bridle against the idea of its ever being enforced.

But it is reasonable to hope that through a better understanding of happiness, we may eventually improve the chance of people attaining it. In the meantime, at least the wonders of science and nature, from smiley-face DNA to footwear for penguins (see page 412), may provide some happiness simply in and of themselves.