Just like all measurable biological and behavioral attributes, people vary in terms of their degree of optimism vs pessimism. However there is a long recognized bias towards optimism. On average, we tend to view the world through the metaphorical rose-tinted glasses. This is just one of the many biases that affect how we process and remember information.

A new study looks specifically at the neurological processes that underly this optimism bias. Researchers looked at 19 subjects, asking them to answer a series of questions about their estimate of how likely they were to suffer negative events in the future (like having an accident or getting a serious disease). They then provided them with statistical information about this likelihood, and asked them again to estimate their personal chances of suffering the negative event.

The researchers found, not surprisingly, an optimism bias. Subjects were more likely to update their estimates when the real statistics were more optimistic than their initial estimates, and less likely to update their estimates (or by a smaller amount) when the real statistics were worse than their initial estimates. In other words, they selectively incorporated optimistic information into their world-view, and ignored or downplayed pessimistic information.

Further, they did all this while the subjects were in an fMRI scanner (a functional MRI scan that looks at which brain regions are active in real time). They found:

Distinct regions of the prefrontal cortex tracked estimation errors when those called for positive update, both in individuals who scored high and low on trait optimism. However, highly optimistic individuals exhibited reduced tracking of estimation errors that called for negative update in right inferior prefrontal gyrus.

So – for those subjects who scored highly optimistic, the part of their prefrontal cortex that is involved in updating information was less active when confronted with pessimistic information.

This is interesting from a neuroanatomical point of view. I don’t think it adds much insight into the psychology itself. It has already been established that people will ignore or dismiss information that contradicts what they already believe or want to believe, and will accept information that confirms their beliefs. This so-called confirmation bias has a huge effect on how we perceive and process information, and can give us a false sense of confidence in our beliefs. It seems like they are supported by a mountain of evidence, but that is only because we have systematically biased information filters.

The optimism bias is essentially a specific manifestation of the more general confirmation bias.

For those who are not generally optimistic, they should not entertain the notion that they are therefore free of biases, or have fewer biases on average than others. That is perhaps the most pernicious bias of all – the delusion that we are free from bias (which actually represents the illusory superiority bias). Being free of cognitive biases would mean that one’s cognitive processes are perfectly calibrated to the truth – which seems unlikely.

The point of critical thinking is to be aware of our cognitive biases and to transcend them by applying processes of rigorous logic, reason, and empiricism.

To put this study further into context, it is important to note that our biases specifically manifest as flaws in how we update our model of reality in reaction to new information (a process known as Bayesian analysis). Optimally, we should start with an objective assessment of any question, and then as new information comes in we update that assessment to account for the new information – all of the new information, not just the part we like.

This study confirms what other researchers have found, that this process is generally flawed and biased. We have no difficulty completely discounting information simply because we do not like the implications. We simply don’t update our beliefs with the new information.

All of this may make one wonder why our brains evolved to operate this way. I wrote recently about one benefit of optimism – if we believe we can learn from our mistakes we are more likely to do so. Optimism may motivate us to be more proactive. It also can help reduce anxiety and depression. Apparently these benefits, on the whole, outweigh, or at least partially balance, the negative effects of optimism.

There are documented negative effects to unrealistic optimism. For example, college students who were optimistic about their ability to avoid negative consequences from alcohol consumption were more likely to engage in unhealthy alcohol consumption. Unrealistic optimism may also decrease one’s chances of quitting smoking.

In short – optimism may interfere with our motivation to take precautions and prepare for the future. A little anxiety about the future is a good thing.

In the end we are left with the conclusion, as with many such things, that a balance of optimism and anxious realism is functionally optimal. We want to be optimistic enough to feel that we can improve ourselves and our lives, but we also need to be anxious about negative outcomes enough that we take precautions to prevent them.

It is perhaps helpful to have insight into where we each fall on the curve from pessimist to optimist, and to adjust for our own biases. Of course, it’s easier said than done. But recognizing that these biases exist and that they can dramatically affect our perception of reality is the first step.