You agree with this column

Martha Gill's Irrational Animals column.

Neurons. Photograph: Getty Images.

If you’re reading this, chances are you’ve already decided to agree with it. Here’s the curious thing about curiosity: we tend to seek out information that tells us what we already believe. If your politics veer to the left, you’ll conveniently ignore facts that back the right and avoid places that’ll tell you about them. And vice versa.

Throw a quick glance under the nearest article on the Daily Mail website. Dissenting comments nearly always get “rated down”, even if fairly innocuous, or true. Daily Mail readers, it seems, are instantly repelled by information that doesn’t chime with their beliefs. But then, as a liberal, I’m more than happy to believe this – in fact, I only look at the Mail to confirm my prejudices. Here’s why.

Our brains are programmed to construct a robust model of how the world works and then fine-tune it. As we learn, some circuits get hardened and reinforced and some wither away. The hardened circuits are our short cuts. This means that when we’re standing in Starbucks and see a cylindrical, liquid-filled shape on the counter, we don’t have to spend too long working out what it is. One of these short cuts will tell us it’s a cup of coffee.

Deconstructing this edifice too many times takes a huge amount of resources. We’re not designed for endless self-questioning – which is probably why Alain de Botton has, at the time of writing, almost no hair left. Instead, we look for information that builds on the model we have.

While our fact-filtering brains are great for working out where the nearest Americano is, they don’t make for very good political debate. Once people have aligned themselves with a particular party, there’s very little you can do to change their opinion. They’ll simply “select out” your most compelling arguments and merrily continue believing what they believe. We love putting opposing political pundits together in TV debates but when was the last time you saw them reach a consensus?

The mighty Bush

A study published in the journal Political Behaviour shows just how reluctant people are to engage with facts that don’t support their world-view. In the experiment, conducted in 2005, participants were given fake news stories. These news stories were embedded with false facts: that tax cuts under the Bush administration increased government revenues, that weapons of mass destruction had been found in Iraq and that Bush had banned stem-cell research (he only limited some government funding). After each statement, the researchers put in an unambiguous correction – and then tested the participants to see if they picked this up.

They didn’t. Participants who identified themselves as liberal ignored the correction on stem-cell regulations and continued to believe Bush had issued a total ban. Conservatives not only ignored the corrections on Iraq and the tax cuts but clung even more tenaciously to the false information.

If you’re interested in the truth, it turns out the worst thing to do is to assign yourself a “stance” on an issue. The more you care about your cause, the harder it is to properly engage with the arguments of your opponent. In fact, only one thing will improve political debate – we need to stop being passionate about politics.