4 December 2012
Last updated at 12:52 GMT
When
it comes to happiness, it seems that the young and the old have the
secret. And it turns out what's true for humans is also true for our
primate cousins, explains neuroscientist Tali Sharot.
How does happiness change with age?
Most people assume that as children we live a carefree
existence, then we go through the miserable confusion of teenage years
("Who am I?") but regain happiness once we figure it all out and settle
down, only to then grow grumpy and lonely with every additional wrinkle
and grey hair.
Well, this is utterly wrong.
It turns out that happiness is indeed high in youth, but
declines steadily hitting rock bottom in our mid-40s - midlife crisis,
anyone? Then, miraculously, our sense of happiness takes a turn for the
better, increasing as we grow older.
About the author
Tali Sharot is a neuroscientist at University College, London
•
Dara O Briain's Science Club is broadcast on BBC Two on Tuesday 4 December at 21:00 GMT
• Follow
@BBCScienceClub
This U-shape pattern of happiness
over the life span (high during youth and old age, low during midlife)
has been observed across the globe, from Switzerland to Ecuador, Romania
to China. All in all, it has been documented in more than 70
countries, in surveys of more than 500,000 people in both developing and
developed countries.
How can we explain these counter-intuitive findings?
Does it have something to do with juggling kids and careers
in our 30s and 40s? Apparently not. Even after accounting for the
presence of kids in the household the U-shape pattern of happiness
remains.
Perhaps the pattern is due to generational differences? But
the studies did not follow the same individuals throughout life, but
rather different individuals of different ages.
Could it be that teenagers and the elderly are happier than
the middle-aged because they were born during better times? No, again -
this does not seem to affect the U-shape pattern. It also persists when
other demographic factors are accounted for, including marital status,
education, employment status, and income.
Then, just last month, a group led by
Prof Andrew Oswald from the University of Warwick, reported that happiness of our evolutionary cousins - the great apes -
also follows a U-shape pattern throughout life.
Of course we cannot ask apes to rate their life satisfaction
on a scale from one to 10. But the well-being of 508 apes was estimated
by asking their human care-givers to assess it. Apes, like humans, were
less happy during midlife than when younger or older.
The existence of a midlife crisis in the great ape
strengthens the notion that the pattern of happiness throughout life is
not due to socioeconomic factors. This leaves two likely explanations.
Firstly, "the survival of the happiest" - happiness is known
to be related to longevity. Put simply, the happier live longer, while
the pessimistic die prematurely, possibly because the latter experience
more stress, which impacts on health negatively.
Happy now?
Therefore, the elderly individuals who remain for scientists to
test should be happier than the average 30- or 40-year-olds. But this
only explains the latter half of the U-shape.
Secondly, the U-shape could arise in both humans and apes
because of similar age-related changes in brain structures that
influence happiness. One part of our brain which changes considerably
both throughout the first two decades of our life, and as we move into
old age, is the frontal lobe.
Our frontal lobes mature well into our mid-20s and then start
deteriorating as early as 45. This means that as we develop, we slowly
increase some frontal-lobe function, which we then lose later in life.
One such function is our ability to learn from bad news.
My colleagues and I have found that people tend to
discount the relevance of undesirable information to themselves
(such as news that alcohol is bad for your liver) but readily adopt
good news (being told that red wine is good for the heart). So when
smokers see warning signs on cigarette packets they think: "Yes, smoking
kills - but mostly it kills the other guy."
At the same when we hear the housing market is going up we think: "The value of my house is going to double!"
Using brain imaging techniques we discovered that the
tendency to discount bad news is related to how well regions of the
frontal lobe are coding unexpected negative information.
Now, you may think that discounting bad news can get people
into trouble - for example, causing us to smoke more and save less.
There is some truth to this, but it is also good for our mental health.
Our research shows that the successful incorporation of bad
news is related to depression. Discounting bad news, as most of us do,
presumably allows us to keep a rosy view of the future, and while this
view is not necessarily realistic it does keep us happy.
Happiness around the world
- U-shape pattern is global, but age at which happiness is lowest differs between countries
- Happiness hits rock bottom at 35.8 years in UK; low point in US
only emerges a decade later; in Italy, happiness hits low at 64.2 years
- US citizens are less happy with each passing decade since 1900;
in Europe, happiness declined until 1950 and has been increasing
steadily ever since
- Women are at their least happy at 38.6 years on average; males hit low point at 52.9 years
But the tendency to discount bad
news also follows a U-shape pattern over our lifespan. Kids, teenagers
and the elderly discount unwanted information more than middle age
individuals.
The developmental change in the frontal lobes appears to be
mirrored by our ability to learn from bad news, which in turn could
drive age-related differences in happiness.
So happiness may come at a price - a reduced ability to take into account unwanted information.
In essence, this means that we may need to re-frame health
and safety campaigns, especially those targeted at the young and the
elderly. Instead of, or in addition to, labelling a packet of cigarettes
with the words "SMOKING KILLS", we may want to print "80% of people who
try to quit smoking succeed".
And instead of highlighting the risks of skin cancer on a
bottle of sun lotion, how about highlighting the sun cream's benefits
(fewer wrinkles, healthier-looking skin)?
Will fewer people reach for another cigarette when we focus
on social norms? Will more people protect their skin from UV rays when
we emphasise the positive? Each case needs to be tested.
But given that we now know that people tend to respond to
warnings with "It's unlikely to happen to me" and to the possibility of a
glorious future with "Why not me?" there is reason to believe this may
be so.
Tali Sharot is the author of The Optimism Bias and The Science of Optimism, of which this is an adapted extract