Oswald did observe some interesting differences. For one, the age at which happiness is at its lowest is different around the world. In Britain, for example, happiness reaches rock bottom quite early — at 35.8 years of age — before it starts going up again. In Italy, by contrast, happiness hits its ultimate low much later — at 64.2 years. And while women reach the bottom of the happiness barrel at 38.6 years on average, men reach it more than a decade later — at 52.9 years.
(Oswald observed another interesting divergence in happiness trends: Americans have been growing less happy since 1900. In Europe, however, happiness has been increasing steadily since 1950, after 50 years of decline. Why the difference? We simply don’t know.)
What explains the age findings? One possible answer is that happy people live longer, while pessimistic ones die earlier, so those elderly individuals who remain for scientists to test are happier than the average 30- or 40-year-old.
Another possibility is that older individuals have experienced a larger range of adverse events, so they are less likely to view these events as frightening and consequential; thus, their psychological coping mechanisms may be better.
A third potential explanation is that the decreased ability in older adults to take bad news into account may be enhancing their optimism and thus increasing their happiness. The decline may be connected with age-related changes in frontal lobe function, which is important for incorporating new information into prior beliefs.
The sun will shine
Why would our brains be wired in a way that makes us prone to optimistic illusions? It is tempting to speculate that optimism was selected by evolution precisely because, on balance, positive expectations enhance the odds of survival.
Research findings that optimists live longer and are healthier, along with the fact that most humans display optimistic biases — and emerging data that optimism is linked to specific genes — all strongly support this hypothesis.
But the optimism bias also protects and inspires us: It keeps us moving forward, rather than to the nearest high-rise ledge. To make progress, we need to be able to imagine alternative realities, and not just any old reality but a better one; and we need to believe that we can achieve it. Such faith helps motivate us to pursue our goals.
Sharot is a research fellow in cognitive, perceptual and brain sciences at University College London and author of “The Optimism Bias: A Tour of the Irrationally Positive Brain.” This article was excerpted from the new TED e-book “The Science of Optimism.”