Last summer, given a chance, I regaled friends and family with anecdotes and insights from one of the more intriguing books I’ve read in ages: Drunk — How We Sipped, Danced, and Stumbled Our Way to Civilization, by Edward Slingerland.

The premise will anger modern temperance advocates who argue black-and-whitely alcohol is bad. The book, though, is more an argument for why on earth alcohol came into human lives and why it never went away, evolutionary-speaking. And that means looking at the benefits it brings.

Slingerland, a professor of Asian studies at the University of British Columbia, has effectively done a meta-study of alcohol-related research from disciplines such as archaeology, anthropology, history, neuroscience, psychopharmacology, psychology, sociology, genetics and literature to argue for the social, cultural, and psychological benefits of getting drunk.

While Slingerland does over-emphasise in places — the same point gets made, the same language gets used — he’s a good storyteller and an excellent explainer.

He starts off discussing whether alcohol is an evolutionary “hijack” or “hangover”. The hangover theory says alcohol was once hugely beneficial. It made calories in food both denser and more easily available — a good thing when you’re surviving as a hunter-gatherer. Add in alcohol’s portability and ability to preserve and you’ve got a product that serves humans from an evolutionary perspective. But 10,000-plus years ago alcohol didn’t taste that great so nature gave us a dopamine spike from ethanol as a reward for drinking it: the spoonful of sugar to help the medicine go down.

But once alcohol had helped our ancestors evolve into bigger, stronger versions of themselves, why did it persevere? Today we have energy-dense, well-preserved, easily-available food so we don’t need alcohol. It is the evolutionary hangover.

The hijack theory comes at things from a different direction: that humans actively exploited the design glitch (dopamine buzz) to give ourselves a pleasure that serves no useful purpose.

Both these theories, Slingerland argues, are based on the idea that alcohol is inherently a vice — something bad that nature should have done away with before now but hasn’t got around to. He decides to test the opposite: that alcohol has benefits and has stayed because it serves a purpose.

Take social bonding. For humans from disparate tribes to get together in groups, to build communities, it was helpful to have something that broke down barriers, build trust, glue people together via shared experience. And the answer was beer. Mostly beer, but also other forms of alcohol and – when alcohol was not available – then another psychoactive substance such as mushrooms or cannabis. Those principles still apply today. Alcohol remains a bonding mechanism for groups — from friends, to co-workers, to team-mates, to military units.

The premise is that alcohol (and we’ll stick to alcohol for now) disarms our prefrontal cortex. Intoxication dulls that part of our brain that’s always trying to control things, that’s looking for threats, that’s trying to remain logical. Disarmed, we relax with each other, and let go enough to trust and share.

Drunk book review

Slingerland has examples from history around the power of alcohol — the necessity almost — in diplomatic situations. Many cultures use alcohol to break down barriers. Added to this is that a little bit of alcohol makes us more honest (without the prefrontal cortex engaged we’re bad at maintaining a charade) but equally, it relaxes us enough to spot who’s lying or trying to deceive. In negotiation settings, alcohol is a useful tool in removing barriers to deceit and mistrust. It’s also why, if someone doesn’t drink in these settings they are often questioned as to their motives. Are they staying sober in order to try something tricky? He cites the Red Wedding episode from Game of Thrones as a classic illustration of this, with Lord Bolton refusing to drink because it “dulls the senses” before going on to murder all his drunken “friends”.

Research also shows that people, uninhibited thanks to a dose of alcohol, we are better (faster) problem-solvers, and more creative in our thinking. He cites the Ballmer Peak, attributed to former Microsoft CEO Steve Ballmer, which describes enhanced coding skills as a function of blood alcohol concentration (BAC), delivering above-average programming ability in a small BAC window. Anecdotally, there’s Google’s whisky room where coders go to have a wee dram when they’re stuck on a problem.

Group bonding, diplomacy, trust, creativity — Slingerland argues these are all essential to civilization and therefore, so too is alcohol. And he fully endorses the theory that agriculture arose so humans could make alcohol, with bread coming after beer.

Slingerland does venture to the dark side of nature’s gift in terms of the negative health effects — from traditional adverse personal effects such as liver damage, cancer and alcoholism to societal harms such as violence and drunk-driving. He argues, plausibly, that if alcohol did more harm than good then nature, via evolution, would have found a way to stop us from using it.

Of course, the idea that alcohol is beneficial is built around thousands of years of very low-ABV drinks taken in controlled settings. We’re talking wild ferments of unmodified grains and fruits and other sources of carbohydrate. Ancient beer was not a 6.8 per cent IPA. In that regard he’s sceptical about spirits, saying the relatively modern invention of distilling (a few hundred years versus 10,000-plus years of beer) is bad for us. We were not designed to handle high doses of alcohol and the deleterious effects of spirits are a modern plague that wipes out the benefits of small amounts of alcohol.

He also warns about solo drinking as a modern danger. Drinking was historically a communal activity, often tied to religious rituals and group events. Historically, it was rare for a person to have private access to alcohol — the only way you would get access would be in a public ritual. That public, restricted, nature of drinking offered enough societal control to guard against excess. Today, he says “we can have enough alcohol in our homes to kill an entire village of people — and we can consume as much of it as we want. This is a dangerous development.”

Outside of de-stressing at the end of a long week (a good thing, he says), drinking in isolation, as happens more frequently in modern life, does not serve the greater good.

In the end, he figures, alcohol is neither a hijack nor a hangover. The fact that neither nature, through genetics, nor nurture, via attempts at prohibition, have tempered our desire to get a bit drunk suggests the benefits far outweigh the costs.

He concludes by saying alcohol’s bad rap is because nearly all research into alcohol comes from a moralistic perspective of vice, that any amount of alcohol is a public health disaster and that anything that doesn’t “increase our individual life span or lower our cancer risk is categorically bad”. There is no research, he says, that looks at the broad, long-term benefits of a substance that allows humans to live and work together in a creative, productive society. And no one can really measure the intangible benefit of a Friday night beer that “gives life texture and makes it enjoyable”.