HUMAN language is thought to have been around for at least 10,000 years and for much of that time we’ve not only been talking to each other, we’ve also been theorising about the way we do it. Two-and-a-half millennia before typewriters were invented, Gautama Buddha was warning of the pernicious power of ill-chosen words and Aristotle was compiling a guide to public speaking. By the middle of the 20th century, the burgeoning influence of television was being described by Marshall McLuhan in his famous mantra: “the medium is the message”.

If you’re a little hazy about what the Canadian intellectual actually meant by that observation, a pithy new guide to communications theory sums it up neatly. “McLuhan believed that the channel is more formative for our culture than the message it carries. If the message changes, we simply change our minds. But when the medium changes, we change our behaviour.”

And as The Communication Book points out, with the advent of social media, “McLuhan’s meaning is crystal clear. It’s not what we read on our smartphone that changes our behaviour, but that we are reading it on our smartphone”.

The book, by Mikael Krogerus and Roman Tschappeler, analyses some of the most influential communications theories ever devised, by thinkers such as Sigmund Freud, JL Austin and Sandra Harding. Subtitled 44 Ideas For Better Conversations Every Day, it distils those complex theories and serves them up as a series of useful tips on everything from making small talk to effective apologies and how to come out with your best lines when it matters instead of five minutes after an interview ends. It’s a stimulating read. But after crunching all these theories, I wonder how optimistic co-author Krogerus feels about the state of discourse in the social media age? “I think we are not very good at communicating and I don’t think all those tools help us with our most basic questions,” says the Finnish author. “The bottom line of all communication problems is that we don’t really listen. And this is the same problem people had 2,000 years ago: the basic human problem of not understanding each other.”

Talking to Krogerus over the uber-21st-century medium of WhatsApp, I’m reminded of a series of radio broadcasts on the art of conversation, which were delivered during the late 1990s by Theodore Zeldin. The Oxford academic described conversation as a dynamic interchange from which both parties should emerge with a slightly different outlook, having seen the world from someone else’s perspective. In the final talk, he expressed disappointment that conversationalists have too often avoided speaking honestly, and a wish that the coming new century would be “more adventurous”.

Given the extent of conflict in the world, he added: “I should like some of us to start conversations to dispel that darkness, using them to create equality, give ourselves courage, to open ourselves to strangers, and most practically, to remake our personal world, so that we are no longer isolated by our jargon or our professional boredom.”

Some 18 years into this brave new century, that sounds like a pipe dream. Political discourse, in particular, has never been nastier, as the social media analyst Jamie Bartlett made clear in The Guardian last year. “In a world of social media spats and Twitter storms,” he wrote, “your opponents can’t simply hold a principled, different opinion. They must be bad. They must be incoherent babblers, sinister Machiavellians, politically correct elites or hoodwinked buffoons.”

Bartlett warned that by failing to credit those we disagree with with even a scintilla of principle or good faith makes compromise impossible – “and without compromise, there’s no politics”.

Are our political views becoming more intractable?

“I think what’s happened now is we are no longer having conversations, we are having debates,” says Krogerus. “The bottom line of debate is – I want to be right. And maybe it’s not enough to be right – someone has to be wrong, so my goal is to prove you are wrong and that I am right.

“Debating has always been part of human nature, but what’s new today is that through digital communication tools, we no longer have to look people in the eye. It’s very hard to look someone in the eye and say – ‘You are stupid’, because you will see that that person gets angry or hurt. But if you write it on a social media tool – ‘Hey, you’re wrong’ – nothing happens and that feels good.”

Social media is also blamed for facilitating the rise in “groupthink” – a phenomenon identified in 1972 by Yale psychologist Irving Janis, who argued that people who surround themselves with like-minded colleagues and discourage dissent often make very bad decisions.

Janis blamed groupthink for grave US policy failures over Pearl Harbor and the Vietnam War, and Krogerus cites the investigation into the 1986 Challenger disaster– which partly blamed Nasa’s organisational culture for the US space shuttle catastrophic break-up – as a more recent example. “People knew about the risks,” says Krogerus, “but they didn’t voice that, because they were afraid to stop the process and be the advocates who always said, ‘No, but …’”

Applying the same concept to a bunch of disparate people tapping away on their smartphones may seem like a stretch, but web entrepreneur Eli Pariser has argued that the personalised “filter bubbles” created by internet giants such as Facebook and Google are blinding us to what’s actually going on in the world – which is why Trump’s election came as a surprise to so many liberals. “If you only see posts from folks like you, you’re going to be surprised when someone very unlike you wins the Presidency,” he told The Guardian. Trump, of course, is notorious for sacking anyone who disagrees with him – and, boy, could the world do with a few influential naysayers at the President’s elbow right now.

As Krogerus points out, limiting our conversational bubble to people who think exactly like us tends to make our views more extreme. It also means we are never exposed to evidence that our own opinions may be based on shaky ground.

“It’s very hard to change your opinion,” says Krogerus. “Do we do this less today? I don’t know if there’s any research on that. What I know for sure is the only way to change your mind is to listen. I really think that is the most important skill we all should learn. And not only to listen and wait until it’s your turn to talk, but approach a conversation thinking: the other person knows something I don’t know.

“In my experience, if you have a real-life conversation, we are much more prone to say, OK, maybe you are right. But online – I have never read any commentator under a post writing, after a long discussion – ‘Hey, you know what? You are right.’ No-one does that. So I think the distance that social media creates gives us the feeling that we don’t have to admit that we might be wrong or that we have changed our minds.”

Technological innovation has always been accompanied by doom-mongering, of course, and even the telephone was once feared as an instrument of the devil. Can the worldwide web really be blamed for creating a climate of closed-minded stubbornness?

Sir John Curtice, polling expert and professor of politics at Strathclyde University, points out that politically homogeneous environments – in which people tend to think, act and vote like their peers – have always existed and, while the internet may have removed the geographical boundaries from such groupings, “we shouldn’t think that before social media we were all floating around in very socially and politically disparate environments”.

But doesn’t the stasis of opinion polls over Brexit and Scottish independence suggest that we are in a peculiarly 21st-century state of political lockdown? Curtice argues that while it’s true that attitudes have changed little since the relevant referendums, both polls were at least in part about two fundamental issues – one is an issue of identity and the second is how countries should be governed. These are almost existential questions – ones which, irrespective of the presence of social media, involve people’s sense of emotional attachment, identity and so on.

“This is blue-touchpaper stuff, and it’s long been known that human beings tend to view the world through the prism of how they would like it to be … and the decisions that they’ve made in the past. We are all a bit reluctant to admit that we’ve made the wrong choice.”

The much-vaunted “carnival of democratic engagement” that proceeded Scotland’s 2014 independence referendum was genuine, says Curtice. “During the campaign, attitudes changed. The Yes side may have lost the referendum, but it won the debate and support for independence grew during the campaign.”

The crucial distinction between then and now is that those two “existential referendums” happened, and attitudes have since ossified. “People have made their decision and put an X on the ballot paper,” says Curtice. “That makes it much more difficult to persuade them to change their mind.

“I suspect there are now more people looking at these issues through a partisan lens than would have been the case before the 2014 and 2016 referendums. Some people would argue that means we shouldn’t have held the ballots in the first place – but that’s a whole other argument.”

Indeed. We are where we are, as the PM never tired of reminding us following the EU referendum. But where we are feels like an impasse. How might a significant shift in mindset be triggered?

“We don’t give politicians much quarter to think, reflect and change their minds,” says Curtice, “so maybe there’s something about the rest of us giving politicians more space.” More broadly, “a clever reframing of the argument or some pretty big changes in economic outlook” will be required.

Curtice’s point about the role identity plays in making us resistant to changing our political stance is backed up by a recent neurological study at the University of Southern California. Psychologists there found that when people’s deep convictions are challenged, the part of the brain thought to be linked to self-identity and negative emotions is stimulated. Having your beliefs attacked can feel, the researchers concluded, like you yourself are under attack, triggering a defensive response that makes you even less open to changing your mind.

That slinging insults is no way to achieve your political goals was confirmed by a 2016 social media experiment conducted by researchers at Cornell University, who wanted to know what kind of online posts were most likely to change minds.

They found that calm, evidence-based arguments were more persuasive than those that used superlatives such as “worst” and “dumbest”. People were also more likely to be convinced by posters who use “hedging” language such as “it may be” rather than expressing certainty – suggesting, once again, that bulldozing your opponents will get you nowhere.

Web campaigners might also want to heed the “six principles of persuasion” identified by psychologist Robert Cialdini and summarised in The Communication Book – particularly the reminder that “people prefer to say yes to people they like”.

Meanwhile, another new book, Elastic: Flexible Thinking In A Constantly Changing World, warns that breaking out of our personal echo chambers is vital if we are to develop mental agility. “Much as we may wish to shun those with opposing opinions,” said author Leonard Mlodinow, “studies show that even if we assign no validity to their opinion, it broadens our perspective to speak to people who disagree with us.”

In an interview with the journal Scientific American, Mlodinow also described a favourite technique for boosting his own cognitive flexibility: “I focus on one of my strongly held beliefs. I imagine that someone tells me that the belief is false, and try harder to be open to the possibility that I’m mistaken.

“I ask questions: Why do I hold that belief? Why might others have come to a different conclusion? I try to take that point of view seriously, and to recall times in the past that I was wrong about something, even though I’d been confident of being right.”

Are we brave enough to do this? Mikael Krogerus thinks the key to more open-minded communication may lie in our schools. “People have become quite good at selling ideas, pitching stories and presenting themselves, and we teach people how to write CVs, present homework and papers. What we don’t teach is how to actively listen and understand where the other person is coming from.

“What does that person actually mean and what question should I ask in order to understand them, rather than to challenge them? It’s clear that we have to learn that. Otherwise, we don’t talk to each other, we just hit each other with arguments.”

The Communication Book: 44 Ideas For Better Conversations Every Day, by Mikael Krogerus and Roman Tschappeler, is published by Portfolio Penguin, £9.99