The war in Ukraine has just edged up another notch. It has not been going well for Ukraine in recent months, and this week Joe Biden’s administration made the decision to allow Ukraine to fire US-supplied army tactical missile systems (Atacms) long-range missiles deep into Russia for the first time.

The US policy reversal also put Ukrainian weapons supplied by the UK and France into play. The UK and France had previously indicated they would allow this, once the US had.

This prompted an immediate threat from Vladimir Putin, who signed a decree lowering the threshold for a nuclear strike in response to a conventional attack on Russia or its ally Belarus that “created a critical threat to their sovereignty and (or) their territorial integrity”. On Thursday, reports suggested that Russia might have launched an intercontinental ballistic missile (ICBM) into Ukraine. This suggested to some that some kind of nuclear war was edging closer.

We have been here before, but perhaps not for a very long time. Some may remember the Cuban missile crisis and the tangible felt threat of a nuclear war between the US and the Soviet Union in October 1962. There was considerable public concern over this. And there was enormous relief when it was resolved by means of a secret deal where the US withdrew its nuclear missiles from Turkey (the public understanding at the time was that the Soviet Union had simply backed down).

Amid fears of a possible nuclear war in 2024, some countries close to Russia, ( Sweden, Norway and Finland), have updated their civil preparedness guidelines to help citizens prepare for war, from how to stop bleeding and deal with anxiety (“restrict your news intake” was one piece of advice), to stockpiling bottled water and sanitary products. Germans have been warned to ready themselves for a possible war. While other European countries such as the UK have not yet done anything similar.

Why are some nations more optimistic?

So why are some nations worried and some apparently much less so? Optimism bias is the tendency to overestimate the probability of good things happening in your life and underestimating the probability of bad things occurring. According to one study around 80% of people suffer from some form of optimism bias (the data tends to be western based, primarily from the US and UK).

Those people tend to believe that their marriages will work (it’s only other marriages that fail), and that they will have a long and fulfilling life compared to everyone else. Global crises are not immune to optimism bias. Optimists tend to think, for instance, that it’s other people and future generations that will suffer from the effects of climate change, not them personally.

People in the west do seem particularly susceptible to optimism bias, according to psychologists’ research. Steven Heine and Darrin Lehman, professors at the University of British Columbia, found that Canadians showed more unrealistic optimism than the Japanese. While other research demonstrated a similar result with Americans versus Japanese.

Optimism bias can affect risk perception of both natural disasters and terrorist events and one study found significant cross-cultural differences in perception of risk that did not correspond to actual exposure rates. The Japanese had the highest risk perceptions, North Americans and Argentinians had the lowest risk perception for terrorist events. Another study found that mainland Chinese were more pessimistic than Chinese Americans who were more pessimistic than white Americans.

Russia says nuclear war is edging closer.

There seems to be something distinctive about the American character. A study measured level of general and geopolitical optimism and global and personal worry in Russian and US schoolchildren and adolescents. The researchers found that, in the US, young people were more optimistic about their future and showed less global and personal worry.

Avoiding bad news

So how does optimism bias work? It appears to be associated with specific biases in what people look at and read, and how they process that information. Optimists avoid negative images and negative information to maintain their mood. They avoid seeing bad news. Their brains also process bad news differently. Functional magnetic resonance imaging (FMRI) shows that the processing of negative information is accompanied by a reduced level of neural coding in a critical region of the frontal cortex of their brains (right inferior prefrontal gyrus).

In other words, optimism bias derives from both an attentional bias (we choose to ignore some things, while paying attention to others) and a failure to learn systematically from new undesirable information.

But surely optimism is a good thing? There is clear evidence of this. Optimists live significantly longer and are much less likely to die from cardiac arrest. Optimism also increases the survival time after a diagnosis of cancer. It does this this by reducing stress and anxiety about the future, and optimists consequently have better immune functioning. Belief in a positive future also encourages individuals to behave in ways that can actually contribute to this positive future – so optimism becomes a self-fulfilling prophecy.

That is why people have been trained to become more optimistic using cognitive behavioural therapy. There is also a whole self-help industry devoted to it and with this, a profound cultural shift, critiqued by author and activist Barbara Ehrenreich in her book Smile or Die. She has argued that these high levels of optimism have “undermined preparedness” to deal with real threats. She wrote: “The truth is that Americans had been working hard for decades to school themselves in the techniques of positive thinking, and these included the reflexive capacity for dismissing disturbing news.” The economic crisis of 2008, she argued, was a case in point, there was simply no ability or inclination to imagine the worst. A world war might be a starker example.

It’s possible to take an optimistic view on what is currently going on. The US think-tank, the Brookings Institure, for instance, thinks that Putin is bluffing, and that he is not about to unleash nuclear weapons.

The downside of optimism is, however, that people may not notice the warning signs – and being prepared for the worst is actually an important aspect of human survival.