Why human civilization may owe its existence to alcohol

To some people, alcohol is a scourge on humanity that can do no good. It's true that booze is directly and indirectly responsible for many pitfalls in society, from drunk driving to increased risk for cancer. But what if alcohol was not merely a vice, but one of the triggers that sparked the dawn of human civilization — in essence, the very thing that shifted us from hunter-gatherers to agrarians?

This is a provocative thesis, and one that might upset Puritans. Yet it has some serious adherents, including philosopher Edward Slingerland. Singerland believes alcohol may have helped shaped human evolution from the very beginning, and continues to have positive benefits for society — beyond providing a socially acceptable form of euphoria.

In his 2021 book, "Drunk: How We Sipped, Danced, and Stumbled Our Way to Civilization," Slingerland lays out the case that alcohol may have even been the impetus for humans developing agriculture and complex societies. Slingerland, who is a professor in the Department of Philosophy at the University of British Columbia, has mostly written books on Chinese history and culture.

But this idea so intrigued him that he delved in, finding evidence that, as he writes, "various forms of alcohol were not merely a by-product of the invention of agriculture, but actually a motivation for it — that the first farmers were driven by a desire for beer, not bread." Salon spoke to Slingerland about some of the misconceptions about alcohol's place in human evolution.

This interview has been condensed and lightly edited for clarity.

There's seemingly a lot of interest in civilization sort of being formulated from different intoxicants, especially psychedelics. But I think alcohol can kind of be overlooked in that equation. It was sort of there, at the dawn of history, but we don't talk about that. It's not a good thing.

Well, alcohol's not cool right now. Psychedelics are super cool. Cannabis is pretty cool. So I just think alcohol has kind of been overlooked or even devalued, because it's kind of the drug your uncle uses, right? And alcohol has a lot of problems.

I think one of the more justified reasons that people are worried about alcohol is that it has some negatives that drugs like cannabis and psychedelics don't have. It's much more physiologically harmful than either one of those drugs and it's physically addictive in a way that those drugs aren't. There are some justifications for it, but I think it's primarily fashion. Especially among younger generations, alcohol doesn't have as cool a reputation as these other drugs.

Can we discuss a couple examples of how alcohol played a positive role in the evolution of human civilization? You've talked about how fermentation, brewing and that kind of thing are these chemical processes that predate agriculture, and maybe even predate organized religion.

We've known for a really long time about natural fermentation with yeast. The standard story that I always assumed before I started doing research for the book, and that I think most people learn, is that humans invented agriculture, we settled down into large scale societies, we've grown crops. And then at some point, we figured out by accident that if we left our sourdough starter out too long, it will bubble and something interesting would result. And so we kind of discovered fermentation by accident after we had agriculture.

When I started doing the research, I encountered this movement in archaeology that I think is gaining adherence and seems quite plausible. That's called the Beer Before Bread hypothesis. So 13,000 years ago or so, we're coming together, building these monumental religious sites and feasting. And feasting involved eating meat and other kind of high value items, but also drinking beer. Sites like Gobekli Tepe, [the world's oldest surviving permanent human settlement], we don't have direct chemical evidence, but we have these big vats. They were drinking some kind of liquid. And we know from other sites in the area, they were making beer at this time. In some cases beer, probably laced with psychedelics.

So in that respect, the desire to get intoxicated actually directly led to civilization. It's what motivated hunter gatherers to start cultivating crops and settling down. And you see this pattern around the world, not just in the Fertile Crescent but also Mideast, which is now the modern Turkey area, where agriculture first got started.

But if you look around the world, the first cultivated crops tend to be plants that must have been chosen for their psychoactive properties, not for their nutrition properties. And so that's behind this idea that it's this desire to get cognitively altered that motivated hunter gatherers to settle down and start living in these large-scale societies. [Getting intoxicated] is an ancient behavior. And it actually is, is probably one of the motivations for us creating civilization in the first place.

It's really fascinating to think about this. I like to put myself back in that time period and think: why would people start planting plants on purpose? And how do they figure out "oh, this is the seed that's responsible for this behavior. If I put this in the ground, I can expect this later." That whole cognitive development of cause and effect there. There's a sort of pop science belief — I don't know if it has a lot of credibility — but the idea is that wheat domesticated humans, not the other way around.

Yeah, that's Michael Pollan's argument. If you take a plant-eye view of it, you see humans, serving plants and kind of eliminating their enemies and giving them nutrition. One way to look at it is that these plants domesticated us. I think that it's rhetorically kind of a great conceptual turn.

There is a sense in which we domesticated ourselves in the process of domesticating plants. Hunter-gatherers lived pretty varied lifestyles. Geographically they'd wander around, they ate really varied diets. As a member of a group, you would typically engage in a lot of different activities. You would forage, you'd hunt, you'd be cooking. Once you move into an agricultural community, your life often turns takes a turn for the worst.

Your diet gets more monotonous. Your life probably gets more monotonous. You're stuck in the field, sticking little seeds in the ground instead of wandering around, hunting things. You are crowded together with other people in a way that humans never were before. So you're living in much denser communities.

So if we want to talk about the role of alcohol in domesticating humans, one of the ways that it helped us make this transition is that it helps relieve anxiety and stress. If humans were motivated to settle down and start agriculture by the desire to get intoxicated, the act of getting intoxicated also helped them to adapt to this new lifestyle.

Alcohol also helped create group bonds. Another crucial function of alcohol, in my view, is to help humans overcome these cooperation dilemmas we have. When we're cooperating with strangers, which we do all the time in large scale societies, one of the main functions of alcohol is to downregulate our prefrontal cortex [PFC], the very important part of our brain.

This is also the part of the brain that you need in perfect working order if you're going to deceive someone, fake sincerity or try to trick someone. And that's a problem, these cooperation dilemmas, like the prisoner's dilemma, where to succeed, to get the best payoff, you need to trust another person. But in doing that you make yourself vulnerable to being taken advantage of.

We face these type of cooperation dilemmas all the time in everyday life, on large scales and small scales. And one of the ways alcohol helps with these cooperation dilemmas is it makes us both more trusting and more trustworthy. If you drink some alcohol, you downregulate your prefrontal cortex, you're less able to lie.

Lying is a really cognitively complex activity and the PFC is the center of self-control, focus, suppression of emotions and expressions and desires, delayed gratification. You need to have all that in top shape to deceive someone. If I take a couple of shots of tequila, I'm less able to do that. And so you're more likely to trust me and for good reason.

At the same time, alcohol is boosting the production of these chemicals that make us like other people more and make us feel more bonded to other people. So things like serotonin and endorphins. Alcohol played a role in decreasing our stress, in the face of shifting to this very dense agricultural lifestyle, but also helped us genuinely create new bonds with strangers and other people in a way that was important for us to cooperate on large scales.

It's not an accident that anytime you're getting people together who have potentially differing interests or potentially hostile parties get together, the intoxicants come out. Most of the time, it's alcohol. In places where they don't have alcohol, for whatever reason, it's some other intoxicant that has very similar effects. And that's because people have learned that it's a tool that you can use to lower people's cognitive defenses.

I compare it to how we shake hands to show we're not carrying a weapon. In the same way, when you sit down at a negotiating table with somebody and you eat a meal and you drink, you start drinking alcohol. You're basically taking out your prefrontal cortex and putting it on the table and saying, I'm cognitively disarmed. You can trust what I'm saying, it's more likely to be true. It's not an accident that cross-culturally around the world, you see intoxicants coming out in these social situations. People know consciously or not that it's an important tool.

I kind of want to go back even further in human history and evolution, I've heard that something like 10 million years ago, it's theorized that the planet was warming and that was causing a lot of fruit to fall off and ferment. And that it was actually protective that as human primates, we have the enzymes to metabolize alcohol. A lot of mammals don't have that. To them, ethanol is just complete poison. So the fact that we can eat this fruit that was fermenting was a protective factor that enhanced evolution.

So it's certainly the case that we are part of a group of animals that can metabolize [alcohol's main ingredient], ethanol. And not just primates, but birds as well. And the thing that they all have in common is they eat fruit. If you're a fruit eater, you're gonna need to develop these enzymes, because fruit ripens and starts to ferment, and it's going to have some amount of ethanol in it.

We're part of a lineage of primates that adapted to eating fruit that contained ethanol. And there's some theories that there's increased pressure on us to do this once we moved out of trees. And we were living on the floor of these jungles or in scattered grassland and trees. Now we were eating fallen fruit on the ground that's got a lot more ethanol in it.

One of the things about alcohol, that makes it special is that we've got a dedicated machinery in our body to get it out of us as quickly as possible. Part of its usefulness as a drug is that it has a pretty short half-life in our body.

The drunken monkey hypothesis tries to explain why we have a taste for alcohol. Why do we like it? Robert Dudley at University of Berkeley, this is his thesis, that in our evolutionary past, there was an advantage to being able to detect ethanol.

Ethanol is a pretty volatile chemical — it travels long distances, so you can smell alcohol from pretty far away. His theory is that the smell of ethanol was like a dinner gong. We developed this ability to detect ethanol from long distances, we could follow the smell and find this ripe fruit that was a really big calorie package. And that was adaptive and that's why we have a taste for alcohol.

Ethanol is a pretty volatile chemical — it travels long distances, so you can smell alcohol from pretty far away. His theory is that the smell of ethanol was like a dinner gong. We developed this ability to detect ethanol from long distances, we could follow the smell and find this ripe fruit that was a really big calorie package. And that was adaptive and that's why we have a taste for alcohol.

The problem with [this theory] is that there are substances that aren't carcinogenic and aren't going to hurt your liver and cause you to fall off a cliff because you're drunk. But we chose alcohol. So there's got to be something special, something else going on there.

The Lancet and many other medical journals have come out with these papers stating "There's no safe amount of alcohol to ever be consumed." So where does alcohol fit into our present day?

There's the infamous Lancet study and other similar studies that argue that the net effect physiologically of alcohol is, at best, zero, neutral and probably negative. And there's debate about this. But in a way, I don't really care.

Maybe it is the case that it's a net physiological negative. I think what's really stunted our conversations about this is that we're looking at it purely through this medicalized lens and only in terms of physiological impact. And I think that's just the wrong way to look at it.

My conclusion in "Drunk" is that I think alcohol still has positive roles to play if it's used carefully. But that said, I do argue in the book that alcohol is much more dangerous now than it has been for almost all of our evolutionary history.

Alcohol, for almost all of our history, has come with this built-in safety feature, which is that natural fermentation can only get you so far. Alcohol is actually the result of this biological warfare between yeast and bacteria, who are both trying to get these nutrients. So the yeast kill off the bacteria with ethanol. But eventually they shut themselves down, because they're not infinitely resistant to ethanol, they're just more resistant than the bacteria are. That means that fermentation stops and whatever it is, a beer or fruit wine, doesn't get any stronger.

Historically, yeast kind of pooped out pretty early in that process. So grain-based beers would only get to about 2 percent to 3 percent ABV, alcohol by volume. Fruit wines maybe would get a bit stronger. We've been breeding yeast for thousands of years to make them more tolerant of alcohol, so that we could get stronger and stronger beers and wines. But even with all that effort, we haven't gotten that much farther. Some craft beers can get up into the double digits now, wines tend to max out at about 17 percent ABV [alcohol by volume]. But that's still not that strong.

Then, we figured out how to do distillation on a large scale. Distillation is a trick for getting around this natural limitation of fermentation. You take the alcohol that's produced and you refine it, get rid of as much water as possible and you can get to like 90 something percent ABV. You have vodkas that are that strong. Distilled liquors are still just ethanol, but I think it should really be considered a completely different drug. It's so much wildly stronger than naturally fermented beverages, that our bodies are not equipped to handle that. You start doing shots of 90 something proof vodka or tequila, and our physiology is completely overwhelmed. That's more dangerous.

Traditionally, alcohol was always consumed in communal, social, ritual contexts, with built-in rules about drinking, ways to kind of regulate people's consumption rates, ways to stop people when they've had too much. That's another safety feature that's been disabled. Right now from my apartment in Vancouver, I can call my local liquor store and have them deliver a case of tequila to my house. And then I can sit here alone in my house in front of the TV and drink as much of it as I want.

That is also evolutionarily unprecedented. Private access to alcohol is unprecedented. So you combine the two, now we have private access to alcohol, and we have private access to this super powerful, very dangerous form of alcohol. Alcohol has become a more dangerous tool. And so we have to be even more careful about using it than we have been historically.