A while back, in this column, I made a plea for more escapism. I’d been driven round the bend by the impossibility of having a single conversation with anyone without the subject turning to politics – Trump or Brexit, mainly – and by the mystifying popularity of TV shows and novels with something to say about “the current climate”, when clearly what’s required is a break from that climate. Read swashbuckling adventures or watch period romances instead! When politics is everything, it’s unhealthy; indeed, as the philosopher Robert Talisse argues, it’s unhealthy for politics itself. (Constructive political disagreement requires that we start from some shared, non-political common ground, otherwise it’s just a fight to the death.) So did you heed my advice? You did not. Though to be fair, neither did I. And neither, apparently, did the participants in a new study by the neuroscientist Tali Sharot and others, on the troubling phenomenon they label “epistemic spillover”.

The experiment was complex, but the findings were stark: once you know someone’s political leanings, it distorts your ability to judge their expertise in domains unrelated to politics. People would rather hear from experts who agree with them politically, and are more influenced by their advice – even if the topic is dentistry, or saving for retirement, or building an extension to your kitchen, or something else entirely non-political. Surely it shouldn’t matter if your dentist or builder disagrees with you on Brexit, or the merits of Jeremy Corbyn? Addressing a US audience, the researchers gave the example of discovering your dermatologist was Republican: “Knowing a person’s political leanings should not affect your assessment of how good a doctor she is.” Yet it does.

Hold on, though. Is it true you should trust a Republican doctor? (Let’s assume this is a context where moral issues such as abortion don’t arise.) Much of me wants to think so. But part of me can’t help recalling the surveys suggesting most Republicans don’t think humans cause climate change, and believe guns make homes safer. If you’ve swallowed those notions, what might that say about your grasp of other scientific data, or your susceptibility to believing whatever you like when it comes to, say, psoriasis, or skin cancer?

The more general point here is that politics, in colonising everything, has come to colonise our perception of the facts, too. And even if you disagree with me on climate change or guns, by the way, the problem remains: perhaps I’m the one labouring under delusions, but either way, we’re arguing not about opinions, but reality itself. In that situation, it’s not necessarily irrational to distrust one’s political opponents on pretty much everything.

It’s a vicious circle: it would be better if politics weren’t so tribal, but given that it is – and that this now extends to basic facts – there’s an incentive to start behaving more tribally yourself. After all, if the other side is out of touch with reality, engaging sanely with reality means rejecting their whole worldview, not just their politics. Is it possible to do that without rejecting them as human beings, thereby turning politics into all-out war? I suppose we’ll soon find out.

Read this: In her 2017 book We Need To Talk, the American journalist Celeste Headlee investigates why we’re so remarkably bad at listening to other viewpoints, and offers strikingly useful tips for better conversation.

oliver.burkeman@theguardian.com