Do you like to look on the bright side of life? Chances are the answer is no, according to psychologists. New findings show that our long-held belief in “optimism bias” might not be as valid as we thought.

To understand this better, we’ve unpacked what exactly optimism bias is and what the new research shows.

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What is optimism bias?

For decades experts have believed it is normal to expect good things to happen in the future and underestimate the possibility of bad outcomes – a trait known as “irrational optimism bias”.

What effect do we think that optimism bias has?

Optimism bias can affect the way policy-makers deal with issues ranging from the financial crises to obesity and climate change.

It can even be taken into account by the Government when planning and funding large infrastructure projects, it is claimed.

We originally thought that large infrastructure projects like HS2 could be affected by optimism bias (HS2/PA)

What does the new study show?

However, a new study suggests that these assumptions about optimism bias may be based on flawed research. After re-assessing the evidence scientists concluded there was no basis for the claim that optimism bias is fundamental to human psychology – perhaps our dispositions aren’t as sunny as we once thought.

What do the scientists say?

Study author Dr Adam Harris, from University College London, said: “Previous studies, which have used flawed methodologies to claim that people are optimistic across all situations and that this bias is ‘normal’, are now in serious doubt. We need to look for new ways of studying optimism bias to establish whether it is a universal feature of human cognition or not.

University College London (Tim Ireland/PA)

“This assumption that people are optimistically biased is being used to guide large infrastructure projects, with the aim of managing expectations around how much projects will cost and how long they will take to complete. Our research supports a re-examination of optimism bias before allowing it to guide clinical research and policy.”

How were the results collected?

Research has suggested that people fail to learn from bad news when told the actual chance of experiencing a negative life event, such as cancer. This is said to provide support for optimism bias.

For the new study, computer simulations were designed to behave in a completely rational way when faced with the psychological test of learning from good versus bad news.

Computers: much more rational than humans (Jeff Chiu/AP)

The programs were not capable of optimism and unable to show bias. Yet they produced the same data patterns that have previously been interpreted as showing evidence of optimism bias.

The research showed how apparent optimism can arise from purely statistical processes. Optimism bias is merely a statistical artefact that arises because of the relative rarity of negative events, according to the findings published in the journal Cognitive Psychology.

Co-author Punit Shah, from King’s College London, said: “There is ample evidence for optimism bias in various real-world situations – England football fans for example – but these instances simply show that certain people might be optimistic in certain situations; not that they are generally optimistic.”