Paul Biegler asks whether the way we form our beliefs means we’re hardwired to succumb to global warming.

In January 2012 physicist Stephen Hawking decided to celebrate his birthday early, with a warning of apocalypse: “I think it is almost certain that a disaster such as nuclear war or global warming will befall the Earth within a thousand years” (BBC Radio 4 interview, 6th Jan 2012). Further souring the ambience, he warned that during “a period of unprecedented climate change, scientists have a special responsibility once again to inform the public and to advise leaders about the perils that humanity faces.” In the wake of ex-UN Climate boss Yvo de Boer’s salvo that the UN’s 2014 Climate Report would “scare the wits out of everyone,” Hawking’s words have fresh oxygen, albeit with lashings of carbon dioxide, too.

But if the physics professor hoped to avert Armageddon by playing Jeremiah, he failed to spot a flaw in his formula. Warning the public is one thing. Having them accept, and then act on, this dire forecast, is another. While the evidence for human-induced global warming has gained substance, the population of naysayers remains decidedly bulky too. A 2012 Gallup poll found only 52% of Americans believe the effects of warming are upon us, down from an earlier 61%; and on causation, just 53% concurred that warming was anthropogenic. Why do so many people, in the face of so much evidence, remain so staunchly unconvinced?

A first guess might be that they just think the science is wrong. Yet the most contentious science – modelling the warming rate and so the imminence of environmental jeopardy – baffles even many experts. Rather, then, many attitudes seem to be shaped by the ‘manufacturers of doubt’, whose minority opinion has gained an over-represented toehold in the popular media. The result is a ‘sampling error’ about the strength of scientific evidence on the issue: disproportionate weight accorded to dubious data breeds erroneous conclusions. Exhortations to downsize our carbon footprint can also cause backlash. Reaction against being told what is good for us is widespread. The ‘boomerang’ effect has proven especially challenging for initiatives to reduce adolescent smoking.

But there is another candidate to explain our reticence to embrace the painful but credible truth of a warming planet. The idea of wishful thinking – we believe what we wish to be true – is hardly new. But its scientific investigation took off in the early 1990s in the wake of a fêted article by the late social psychologist Ziva Kunda, ‘The Case for Motivated Reasoning’.

Biasing Your Own Thinking

‘Motivated reasoning’ describes how emotional commitments affect the way we process information. To see how, try a thought experiment. Imagine visiting your doctor with a cough. If your hacking is extreme, your GP might cave in and order a chest X-ray. Now imagine, when returning for the results, that your physician is uncharacteristically grave: “I’ll be straight up. The news isn’t good. There’s a growth that looks suspiciously like a tumour. We’ll need to arrange some further tests.” If you’re like most, your first response will be disbelief: “Doctor, are you sure? Couldn’t you have mixed up the X-rays? Is the radiologist mistaken? Can I get a second opinion?” Bad news is an unwelcome visitor, and doesn’t cross your threshold without a fight. There would be no such remonstrations if the X-ray were clear. Instead, with relief and an inner smile, you’d settle up with the receptionist and be blithely on your way. There’s little resistance to a diagnosis of good health.

This vignette depicts a famous type of motivated reasoning: confirmation bias. We tend to accept information that agrees with our take on the world, and to discount data that contradict it. Many studies affirm this. People told they scored low on an IQ test prefer articles that criticise rather than support the test’s validity; and women who drink a lot of coffee were quicker to note flaws in a fictional study linking caffeine consumption and breast cancer.

So, do people reject the forecast of global warming doom because it upsets their worldview?

Read the full article in Philosophy Now magazine here or download the pdf here