Think happy thoughts

24 March 2010

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Smile. colodio/Flickr

This post is going to be great, don’t you think?

If you do, that might be because you have an ‘optimism bias’.

According to Dr Tali Sharot, a neuroscientist from the Wellcome Trust Centre for Neuroimaging, around 80 per cent of the population tend to overestimate the positive outcomes and underestimate the negative in a given situation. For example, most people think they will live longer than others, have more success in jobs, marriage or believe they are less likely to suffer an accident.

The neurological basis of optimism is Sharot’s specialism and the subject of her talk at the latest Packed Lunch at Wellcome Collection. Her studies have found that people are unaware of this optimism bias and do not correct it, even when confronted by facts that seem to contradict their view.

In one study, subjects were asked to rate the likelihood of different things happening to them, such as getting cancer, before being told the actual average probability. Sharot found that people undertake a form of ‘selective updating’ – they don’t adjust their bias for information that contradicts their optimism, but they do take in information when it reinforces their point of view or describes a situation better than they had imagined.

It’s not that people don’t remember negative information; they just don’t regard it as relevant to themselves. Or more specifically, we learn more from information that reinforces our bias than information that contradicts it. Optimism bias, said Sharot, is about self, and maybe friends and family, but not society. Studies have shown that people generally think of their own personal situation as good, even if society in general is not. The financial crisis, for instance, might have you thinking that the economy is bad, but you’ll be okay.

What is the evolutionary benefit of optimism? Well, optimists tend to live longer than pessimists and it’s been shown to correlate with better survival rates in AIDS patients and lower risk of cardiac arrest. Optimism is related to better physical condition and, said Sharot, if you are more optimistic you are obviously less likely to get stressed out or suffer from anxiety. But it also affects your approach to life – if you expect a positive outcome you are more likely to take a risk, pursue your dreams, or even just get up in the morning.

Of course, it’s not all good (sorry, that’s the pessimist in me) – an extreme optimism bias can have a negative effect. Studies have shown that those with a mild optimism bias have better investment portfolios, longer-lasting marriages and are less likely to smoke, compared to those with an extreme optimism bias. This is perhaps because they don’t take silly risks under the mistaken assumption that they’ll get away with it. As Sharot said, “If we underestimate risk we may not bother getting insurance or undergo medical screening.”

Of course, people tend to engage in positive thinking more than negative. But what’s interesting is that they tend to imagine positive events as being closer in time (I will win an award… soon), and in more vivid detail, compared to negative events (I may get cancer, but not for many years to come).

This propensity to accentuate the positive is what originally sparked Sharot’s interest in this area. She actually started out studying traumatic memories, but became interested in how the brain systems used to record our past – the hippocampus and parts of the subcortical region of the brain – are the same systems used for imagining the future. Sharot was intrigued by the way that emotion changes our memories and how it alters the way we think about the future.

She described one early experiment where volunteers were asked to imagine fairly routine events but always seemed to imagine a magnificent future. For example, a haircut turned into a fully-fledged charity campaign for Locks of Love culminating in the act of hair cutting to thunderous applause in front of their friends and family. Another participant was asked to imagine a ferry ride and thought of a ride to the Statue of Liberty with her hair flowing elegantly in the wind. This is the power of positive bias, such that even when asked to imagine an unpleasant event, such as losing your keys, subjects imagined a scenario where they got into that situation but then got out of it.

Another interesting area of study is in the realm of cognitive dissonance, where justifying or rationalising your choice or behaviour reduces the unpleasantness of holding two contradictory ideas. For example, Sharot’s team asked volunteers to rate different holiday destinations, then to choose between two destinations they had rated previously the same. People expect to be happy with their choice and, when asked afterward to rate the destinations again, end up unconsciously rating their selected destination as better, even though they originally rated them the same.

From an evolutionary perspective, this is useful as it reinforces our commitment and means we don’t second guess ourselves, agonising in a pit of regret. And of course, it helps enhance our pleasure by feeling that we’ve made the right choice.

A sense of control enhances our sense of optimism – there’s the perception that by choosing lottery numbers you increase your chances of winning. Optimism is both a self-fulfilling prophecy and a bias.

Sharot’s research, using fMRI brain imaging, has demonstrated that when we think positively about the future we use in particular two areas of the brain: the rostral anterior cingulate cortex in the frontal lobe and the amygdala in the subcortical region, which is involved in processing, detecting and expressing emotion. The interaction between these two is greatest when we imagine positive future events.

Researchers think that these two areas are those that are malfunctioning in depression and studies have found that activity in these regions is reduced in depressed subjects (in terms of optimism bias, depressed people are actually more realistic and accurate in their assessment of the future). If they can work out exactly how these systems work, and how they breakdown in depression and other mood disorders, they may be able to develop better treatments to help. And that really is something to hope for.

Mun-Keat Looi is a Science Writer at the Wellcome Trust.