The psychology of belief explains America’s ongoing war with Darwin

One hundred years after a Tennessee teacher named John Scopes started a legal battle over what the state’s schools can teach children, Americans are still divided over evolution.

Scopes was charged with violating Tennessee law by teaching evolution, in a highly publicised July 1925 trial that led to national debate over evolution and education. The trial tested whether a law introduced that year really could punish teachers over evolution lessons. It could and did: Scopes was fined US$100 (£74).

But here’s the weird part: while Americans remain deeply divided about whether humans evolved from earlier species, across the Atlantic British people had largely settled this question decades before the Scopes trial.

According to thinktank Pew Research Center data from 2020, only 64% of Americans accept that “humans and other living things have evolved over time”. Meanwhile, 73% of Britons are fine with the idea that they share a common ancestor with chimpanzees. That nine-percentage-point gap might not sound like much, but it represents millions of people who think Darwin was peddling fake news.

From 1985 to 2010, Americans were in what researchers call a statistical dead heat between acceptance and rejection of evolution – which is academic speak for people couldn’t decide if we were descended from apes or Adam and Eve.

Here’s where things get psychologically fascinating. Research into misinformation and cognitive biases suggests that fundamentalism operates on a principle known as motivated reasoning. This means selectively interpreting evidence to reach predetermined conclusions. And a 2018 review of social and computer science research also found that fake news seems to spread because it confirms what people already want to believe.

Evolution denial may work the same way. Religious fundamentalism is what researchers call “the strongest predictor” for rejection of evolution. A 2019 study of 900 participants found that belief in fake news headlines was associated with delusionality, dogmatism, religious fundamentalism and reduced analytic thinking.

High personal religiosity, as seen in the US, reinforced by communities of like-minded believers, can create resistance to evolutionary science. This pattern is pronounced among Southern Baptists – the largest Protestant denomination in the US – where 61% believe the Bible is the literal word of God, compared to 31% of Americans overall. The persistence of this conflict is fuelled by organised creationist movements that reinforce religious scepticism.

Brain imaging studies show that people with fundamentalist beliefs seem to have reduced activity in the dorsolateral prefrontal cortex – the brain region responsible for cognitive flexibility and analytical thinking. When this area is damaged or less active, people become more prone to accepting claims without sufficient evidence and show increased resistance to changing their beliefs when presented with contradictory information. Studies of brain-injured patients show damage to prefrontal networks that normally help us question information may lead to increased fundamentalist beliefs and reduced scepticism.

Fundamentalist psychology helps explain the US position in international evolution acceptance surveys. In a 2006 study, of over 33,00 people from 34 countries, only Turkey ranked lower than the US, with about 27% accepting evolution compared to America’s 40% at the time. Among the developed nations surveyed, the US consistently ranks near the bottom – a pattern that persists in more recent international comparisons.

Research shows that political polarisation on evolution has historically been much stronger in the US than in Europe or Japan, where the issue rarely becomes a campaign talking point. In the US, anti-evolution bills are still being introduced in state legislatures.

In the UK, belief in evolution became accepted among respectable clergymen around 1896, according to church historian Owen Chadwick’s analysis of Victorian christianity. But why did British religious institutions embrace science while American ones declared war?

The answer lies in different approaches to intellectual challenges. British Anglicanism has a centuries-old tradition of seeking a “via media” – a middle way between extremes – that allowed church leaders to accommodate new ideas without abandoning core beliefs. Historian Peter documented how British religious leaders actively worked to reconcile science and religion, developing theological frameworks that embraced scientific discoveries as revealing God’s methods rather than contradicting divine authority.

Anglican bishops and scholars tended to treat evolution as God’s method of creation rather than a threat to faith itself. The Church of England’s hierarchical structure meant that when educated clergy accepted evolution, the institutional framework often followed suit. A 2024 paper argued that many UK church leaders still view science and religion as complementary rather than conflicting.

A different approach

The British experience proves it’s possible to reconcile science and faith. But changing American minds requires understanding that evolution acceptance isn’t really about biology — it’s about identity, belonging, and the fundamental question of who gets to define truth. People don’t reject evolution because they’ve carefully studied the evidence. They reject it because it threatens their identity. This creates a context where education alone can’t overcome deeply held convictions.

Misinformation intervention research suggests that inoculation strategies, such as highlighting the scientific consensus on climate change, work better than debunking individual articles. But evolution education needs to be sensitive. Consensus messaging helps, but only when it doesn’t threaten people’s core identities. For example, framing evolution as a function of “how” life develops, rather than “why it exists, allows for people to maintain religious belief while accepting the scientific evidence for natural selection.

People’s views can change. A review published in 2024, analysed data which followed the same Gen X people in the US over 33 years. It found that, as they grew up, people developed more acceptance of evolution, though typically because of factors such as education and obtaining university degrees. But people who were taught at a private school seem less likely to become more accepting of evolution as they aged.

As we face new waves of scientific misinformation, the century since the Scopes trial teaches us that evidence alone won’t necessarily change people’s minds. Understanding the psychology of belief might be our best hope for evolving past our own cognitive limitations.

This article is republished from The Conversation under a Creative Commons license. Read the original article.