Monty Python told us to ‘always look on the bright side of life’, but it seems optimism isn’t as ingrained in human nature as previously thought, a new study claims.  

Researchers have found that humans aren’t predisposed to optimism, nor do we go around with ‘a pair of rose-tinted glasses’ – a belief that may have biased the findings of previous studies. 

The experts cast doubt over past research supporting the existence of ‘irrational optimism bias’ – that humans innately have a feeling that everything will be alright.  

Glass half full or half empty? A 'sizeable body of literature' suggests people's belief updating - beliefs to take into account a new piece of information - is optimistically biased, such that their beliefs are updated more in response to good news than bad news. The new research paper refutes this idea, however

Half full or half empty? A ‘sizeable body of literature’ suggests people’s belief updating – beliefs to take into account a new piece of information – is optimistically biased, such that their beliefs are updated more in response to good news than bad news. This idea is refuted by the new research paper.


A person’s ‘irrational optimism bias’ is when they focus too much on the positive side of life.

They underestimate the likelihood of experiencing negative events and overestimate the chances of positive experiences.

According to researchers, irrational optimism bias can cause financial crises, inaction on climate change, and failure to look after one’s health. 

They say that the UK government also considers this tendency when planning large infrastructure projects. 

Researchers now believe that there are flaws within the research supporting the existence an irrational optimism bias.

Researchers at Birkbeck University of London and University College London carried out the new study.

Although they don’t believe that irrational optimism is absent, the authors acknowledge that previous optimism research may have been affected by an assumption that it is an innate part human nature. 

They say prior scientific studies have generated ‘false positives’ – data patterns that look like people are being over-optimistic, where no such bias exists. 

Jason Burton, study author at Birkbeck, stated that “our experiments show that the method commonly used for such optimism is flawed, giving birth to “optimistic belief updating where optimism cannot be achieved.” 

“This is not to suggest that optimism bias cannot exist in real life, but that better methods are required. 

“Essentially, current methods yield false positives.”       

The researchers used an approach that has been widely accepted in past optimism research for their study to conduct several experiments. – known as ‘the update method’.

This method involves participants estimating their chance of experiencing a life event and then re-estimating it after being provided with the average person’s actual chance of experiencing the event – known as ‘belief updating’.

Typically, this has been done with negative life events, like contracting a disease or getting a divorce – in other words, various forms of bad news cases that would elicit a strong emotional response. 

Humans aren't predisposed to optimism, nor do we go around with 'a pair of rose-tinted glasses' (stock image)

Humans don’t have the genetic disposition to be optimistic.


One expert said that thinking too positively can make it difficult to achieve your goals and lead to complacency. 

‘There is no doubt that a simplistic view of positive thinking…can be dangerous,’ Tim LeBon, a psychologist at City University London, told MailOnline. 

There is ample evidence that fantasizing about a better future can lead to complacency.

You also expose yourself to being shocked and distressful if things don’t go your way in the future.

MailOnline was told by Mr LeBon that it would be a mistake to think positively and instead think negatively.

“We must be able to see the power of both positive as well as negative thinking.”

Positive thinking is important because of its ability to motivate and keep us motivated to reach the goals we set.

However, thinking negatively can help us prepare for setbacks and failures so that we are ready to handle them when they happen.   

A participant might be asked to rate their chances of experiencing a negative life event such as divorce, and they might answer 5 percent. 

They’re then presented with the actual proportion of the general population that gets divorced in their lifetime – 45 per cent – before updating their belief. 

The bad news is that the chances of divorcing are higher than anticipated. This is considered ‘undesirable’ information. 

Researchers explain in their paper that trials in which participants are provided with desirable information tend to elicit more updates than trials that contain undesirable information. This is thought to be evidence of optimism in belief updating. 

Researchers used the same “update method” but removed the emotional component to conduct this new study.

Instead, they used neutral and non-emotional examples like participants estimating the likelihood of the next car passing being black or the likelihood of them getting a haircut within four weeks.

Despite changing the examples, and removing the emotional components from the questions the same optimistic pattern was observed.

This simply proved that it wasn’t the element of optimism that was changing their beliefs, leading the team to challenge the validity of the methods used in other research claiming to prove optimism bias. 

MailOnline heard from Punit Shah (associate professor at Bath’s department of psychology) that “what we really mean is that, once emotional aspects have been removed, there should technically no optimistic patterns for changing beliefs.”

‘By definition the removal of emotion makes obtaining good or bad news about life’s chances impossible. 

“That beliefs about neutral events are still changing is a sign that this task is not measuring optimism, but a statistical artifact.”

Researchers argue that valence – whether information is good, bad, or neutral – is essential to the claims supporting the existence of optimistic ‘belief updating’.  

Shah said that while there is evidence for optimism in some situations, the team does not deny that humans are generally optimistic. 

Eric Idle (left) and Graham Chapman sing 'always look on the bright side of life' in the final scenes of Monty Python's Life of Brian (1979). But humans aren't as predisposed to optimism as we may have been led to believe

Graham Chapman and Eric Idle sing “always see the bright side of the life” in the final scenes of Monty Python’s Life of Brian (1979). Humans are not as predisposed towards optimism as we might have been led to believe.

‘We are certainly not saying that optimism doesn’t exist, or that people are not overly optimistic in certain situations – e.g. For weak teams, sports fans.

“But our research questions whether optimism bias is a default mode for human operation as many have argued for many decades.”

According to researchers, irrational optimism bias can cause financial crises, inaction on climate change, or people’s failures to look after their own health. 

Shah stated that although researchers and policy-makers have built careers on the idea of optimism biases, it is time to reconsider evidence.

Large government projects are governed by the ‘optimism bias’. This is to control projections about financial and time costs. 

“Our latest research builds upon our previous research and supports a review of optimism bias before it guides any policy further.”       

The journal Cognition published the new study. 

PESSIMISTS ARE WO years earlier than the average person – BUT being an OPTIMIST does not mean you live a longer life. 2020 STUDY FINDS 

According to a 2020 study, people who are pessimistic will die sooner than those with more positive or negative views.

Researchers discovered that people with negative outlooks on the future or the present died two years earlier than the average person. 

Surprisingly, however, it was not shown that being optimistic can increase life expectancy. 

The team, from QIMR Berghofer Medical Research Institute in Brisbane, Australia, said pessimists likely do not look after themselves as well, resulting in their health declining sooner than the health of others.

Previous studies have found an association between optimism and pessimism and certain disease, or lack thereof. 

However, such research had grouped them onto one scale instead of separate scales. As a result, people with low scores are classified as optimists.  

Dr John Whitfield, a QIMR Berghofer clinical biochemist, stated that optimism and pessimism do not have to be opposites.

“The key feature of our results was that we used two separate scales for measuring optimism and pessimism, and their association with all causes. 

For the study, published in the journal Nature, the team looked at a questionnaire of around 3,000 participants aged 50 or older. 

The questionnaire was part a Life Orientation Test that examined the health of Australians between 1993-1995. Follow-up information is only available up to the end 2009.

Participants were given a score on an optimism-pessimism scale based on how  much they agreed or disagreed with optimistic and pessimistic statements.  

This statement could be: “I’m always optimistic for my future” or “If anything can go wrong for you, it will.” 

Pessimists who scored higher  [were likely to die two years earlier on average than those who did not rate as pessimistic.]

Pessimists were less likely to die from cancer and cardiovascular disease than those who were optimistic.

Moreover, depression and mood disorders like pessimism did not seem to have any effect on the link between mortality and pessimism.  

Whitfield doesn’t believe the disease causes pessimism, although it’s not clear why they die earlier.

According to him, people who are pessimistic might not be able to look after their health and themselves – they might think it’s pointless following advice about diet and exercise.

“There are indications that optimism and pessimism can have an effect on brain and blood biochemistry, inflammation possibly on the arterial wall.

Researchers also found that optimism scores were not associated with a shorter or longer life expectancy.

There was no statistical difference in the optimism or pessimism scores of men and women.