Drunk: How We Sipped, Danced, and Stumbled Our Way to Civilization

by Edward Slingerland

One type of evolutionary mistake can be thought of as an evolutionary “hangover,” where we are plagued by behaviors and drives that were once adaptive, but are no longer. Our desire for Twinkies is a classic example of an evolutionary hangover. Junk food is appealing because evolution built us to like sugar and fat. This was a sensible strategy for our ancestors, hunter-gatherers haunted by the constant specter of hunger and starvation.

Evolution can also be subverted by “hijacks.” These are cases where we’ve figured out an illicit way to tap into a pleasure system originally designed to reward other, more adaptive behavior. Masturbation is an exemplary hijack. Orgasms are meant to reward us for having reproductive sex, thereby helping our genes get into the next generation.

Whether of the hangover or hijack variety, evolutionary mistakes persist because natural selection hasn’t bothered to deal with them yet. This is typically because whatever costs they involve are either relatively minor or have only become problematic quite recently.

It takes well over twenty years to fully develop the PFC, a physiologically expensive part of the brain, and the last to reach maturity. It is therefore odd that one typical way to celebrate a twenty-first birthday is to chemically knock it down a few pegs.

In fact, archaeologists have begun to suggest that 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.5

My central argument is that getting drunk, high, or otherwise cognitively altered must have, over evolutionary time, helped individuals to survive and flourish, and cultures to endure and expand. When it comes to intoxication, the mistake story cannot be correct. There are very good evolutionary reasons why we get drunk.

This book argues that, far from being an evolutionary mistake, chemical intoxication helps solve a number of distinctively human challenges: enhancing creativity, alleviating stress, building trust, and pulling off the miracle of getting fiercely tribal primates to cooperate with strangers. The desire to get drunk, along with the individual and social benefits provided by drunkenness, played a crucial role in sparking the rise of the first large-scale societies. We could not have civilization without intoxication.

As the anthropologist Michael Dietler notes, “Alcohol is by far the most widely and abundantly consumed psychoactive agent in the world. Current estimates place the number of active consumers at over 2.4 billion people worldwide (or roughly one third of the Earth’s population).”1

Although we do not tend to think of tobacco as an intoxicant, the strains cultivated by Native Americans were much more powerful and intoxicating than what you can now buy at your corner store. When mixed with hallucinogenic ingredients, as it typically was, it really packed a punch.

When it comes to explaining our taste for alcohol, perhaps the most prominent hangover theory is the “drunken monkey” hypothesis advanced by the biologist Robert Dudley.34 In the tangled rain forests where humans first evolved, alcohol is produced in ripe fruit by yeast cells as part of their chemical warfare campaign against bacteria, which are less tolerant of alcohol and compete with the yeast for the fruit’s nutrients. Alcohol therefore owes its very existence to a vicious history of yeast-bacteria warfare. Dudley argues that an incidental feature of the molecule that we call alcohol (technically, ethanol) is the key to why primates acquired a taste for it. Ethanol is extremely volatile—that is, it is a small, light molecule that can travel long distances in the air. It is therefore ideally positioned to function as an olfactory dinner gong for a wide variety of species. This no doubt includes fruit flies, whose taste for alcohol is probably linked to its ability to lead them to fruit. It is Dudley’s contention that this was also the case for early humans, as well as our primate ancestors and cousins, who—following the waft of alcohol molecules to find and identify the rare prize of ripe fruit—came to associate small amounts of alcohol with high-quality nourishment.

Other hangover theories argue that the fermenting of grains and fruits plays a useful role in converting their calories into a more durable, portable form, allowing the preservation of resources that would otherwise be lost in a world without refrigerators.36 Alcohol, in this view, traditionally functioned like a more fun version of kimchee or pickles.

Another advantage of fermentation, at least when we’re talking about the transformation of grains into beer, is what the British nutritionist B. S. Platt, observing that fermenting maize into beer nearly doubles its essential micronutrient and vitamin content, called “biological ennoblement.”38 This nutritional transformation, caused by the action of yeast on fermenting grain, could have been particularly important in pre-modern agricultural societies. The archaeologist Adelheid Otto argues that, at least in Mesopotamia, the nutritional content of beer played a crucial role in rounding out people’s “depressingly bad diet,” which otherwise consisted almost entirely of starches and precious little fresh vegetables, fruit, or meat.39 Even as recently as pre-Victorian England, it is thought that beer made up a significant portion of the average person’s caloric intake.40

Another category of hangover theories focuses not on alcohol’s volatility, or ability to preserve calories or add vitamins, but on its germ-killing properties. As we’ve noted, alcohol is designed to kill bacteria, having been produced by yeast as a weapon in their competition with bacteria to gain the upper hand in decomposing fruit and grain. This is why pure alcohol is an excellent disinfectant.

Finally, the process of fermenting alcoholic beverages also has the effect of disinfecting the water from which they are made.

Hangover theories like the drunken monkey hypothesis have received a lukewarm reception among primatologists and human ecologists, who point out that wild primates appear to avoid the kind of overripe fruit that produces ethanol, and that studies with humans suggest we strongly prefer simply ripe (no ethanol) fruit to overripe fruit.45 (I certainly do.) Other hangover theories are hampered by the unfortunate fact that the postulated functions of alcohol or other drugs in our ancestral environment could have been performed just as well by something that doesn’t paralyze large portions of your brain and leave you with a splitting headache in the morning.

Humans in groups are similarly profligate in their modes of worship. In ancient China, a good chunk of GNP was simply buried in the ground with dead people. Visitors to the tomb of the First Emperor of Qin marvel at the detail of the individual terra-cotta soldiers, the fully intact chariots, the awesome spectacle of a full army arrayed to protect the dead emperor. Rarely, if ever, does the question arise of why anyone would build something so monstrously wasteful in the first place. Remember, all of this was built at enormous expense and then simply buried in the ground, along with a disturbing number of freshly sacrificed horses and people. And China is no outlier. Think of Egyptian or Aztec pyramids, Greek temples, Christian cathedrals. It’s a good bet that the largest, most expensive and lavish structure in any pre-modern culture is dedicated to religious purposes. Looked at from an evolutionary perspective, this is all really stupid.

All over the world, wherever you find people, you find ridiculous amounts of time, wealth, and effort dedicated to the sole purpose of getting high. In ancient Sumer, it is estimated that the production of beer, a cornerstone of ritual and everyday life, sucked up almost half of overall grain production.

As the writer Michael Pollan has argued, Johnny Appleseed, whom American mythology now portrays as intent on spreading the gift of wholesome, vitamin-filled apples to hungry settlers, was in fact “the American Dionysus,” bringing badly needed alcohol to the frontier. Johnny’s apples, so desperately sought out by American homesteaders, were not meant to be eaten at the table, but rather used to make cider and “applejack” liquor.58

When it comes to market economies, contemporary households around the world officially report spending on alcohol and cigarettes at least a third of what they spend on food; in some countries (Ireland, Czech Republic) this rises to a half or more.63 Given the prevalence of black markets and underreporting on the topic, actual expenditures must be significantly higher. This should astound us. It’s a lot of money to be spending on an evolutionary mistake.

Take cannabis, for example. THC, the ingredient in cannabis that gets you high, is actually a bitter neurotoxin produced by the plant to avoid getting eaten. All plant drugs, including caffeine, nicotine, and cocaine, are bitter for a reason. The astringent taste is a message to herbivores: Back off, if you eat this it’s going to hurt your stomach or mess with your brain and probably both.

Humans are the only species that deliberately, systematically, and regularly gets drunk.

Living in this niche therefore requires both individual and collective creativity, intensive cooperation, a tolerance for strangers and crowds, and a degree of openness and trust that is entirely unmatched among our closest primate relatives. Compared to fiercely individualistic and relentlessly competitive chimpanzees, for instance, we are like goofy, tail-wagging puppies. We are almost painfully docile, desperately in need of affection and social contact, and wildly vulnerable to exploitation. As Sarah Blaffer Hrdy, an anthropologist and primatologist, notes, it is remarkable that hundreds of people will cram themselves shoulder to shoulder into a tiny airplane, obediently fasten their seat belts, eat their packets of stale crackers, watch movies and read magazines and chat politely with their neighbors, and then file peacefully off at the other end. If you packed a similar number of chimpanzees onto a plane, what you’d end up with at the other end is a long metal tube full of blood and dismembered body parts.6 Humans are powerful in groups precisely because we are weak as individuals, pathetically eager to connect with one another, and utterly dependent on the group for survival.

Hive life is (literally) a no-brainer for ants: They share the same genes, so sacrificing for the common good is not really a sacrifice—if I’m an ant, the common good simply is my good.

As the developmental psychologist Alison Gopnik and her colleagues have observed, general intelligence, behavioral flexibility, ability to solve novel problems, and a reliance on learning from others tends to roughly correlate with an extended period of helpless immaturity.13 This relationship is found across a broad range of animals, including birds and mammals, suggesting that it tracks a fundamental evolutionary trade-off between narrow competence and creative flexibility.

Humans have adopted such an extreme form of the peak-late strategy because, as a species, we have come to inhabit an equally extreme ecological niche. The main demands imposed upon us by the odd, crowded cave to which we have adapted can be summed up with what I’ll call the Three Cs: we are required to be creative, cultural, and communal. The demands of the Three Cs make us, like the helpless, blind, altricial crow chicks, more vulnerable than robust and less complicated animals.

Oedipus faces another crisis in the form of a terrible plague. Some, like the soothsayer Teresias, turn to the gods for guidance, hoping to discern the proper way forward from clues found in the flight of birds or other omens. Oedipus castigates them, recalling his encounter with the Sphinx: Tell us, has your mystic mummery ever approached the truth? When that hellcat the Sphinx was performing here, Tell us: What help were you to these people? Her magic was not for the first man who came along: It demanded a real exorcist. Your birds— What good were they? or the gods, for the matter of that? But I came by, Oedipus, the simple man, who knows nothing— I thought it out for myself, no birds helped me!15 What vanquished the Sphinx was not magic or divine intervention, but the power of human creative insight. As the cultural historian Johan Huizinga notes, riddles that must be solved, upon the pain of death, are a common feature across the world’s sacred mythical cultures. “In its mythological or ritual context,” he observes, “it is nearly always what German philologists know as the Halsrätsel or ‘capital riddle,’ which you either solve or forfeit your head. The player’s life is at stake.”16

No amount of algorithmic chain reasoning or brute force can give you the solution to a riddle: You just need to relax your mind and see the answer in a flash of insight. Psychologists refer to this process, one that is aimed at producing an aha moment, as lateral thinking.

While we might imagine that the brain matures through accumulation, building up more and more neurons in a given region, maturation in fact results from what is called “neural pruning,” the gradual elimination of unnecessary neural connections. A region of the brain becomes mature when it settles down into a lean, functionally well-organized system.

As the play researcher Stuart Brown notes, adult human beings, in both our appearance and playfulness, are essentially the “Labradors of the primate world.”26 We look, and behave, more like chimp babies than chimp adults. Species that display neoteny (like dogs) tend to be more flexible but less efficient and self-sufficient; those showing mature characteristics (like wolves) are brutally efficient but rigid.

Human children, like dog pups, are thus doubly immature: youthful versions of a species that itself retains youthful characteristics.

no single human could hope to produce even the most basic component of an iPhone, or any complex cultural technology, through sheer insight or creativity. Innovations are always necessarily gradual and incremental, building on the accumulated insights of past humans. We are the cultural animal par excellence, and our ability to share the products of our individual creativity and pass them on to future generations is the key to our ecological dominance.30 Moreover, cultures as a whole can figure out the solutions to problems that are, in principle, beyond the capacity of any single individual to solve. As cultural evolutionary theorist Michael Muthukrishna and colleagues argue, we need to think of our brains not just as individual organs sitting in our heads, but as part of an extended network, nodes in a massive “collective brain.”31

The tension between our need to cooperate on a large scale and our individual, primate-driven selfishness appears clearly in the sort of dilemmas inherent to social cooperation. Any time tension arises between the public good and individual interests there is the danger of what economists call “defection,” a situation in which a selfish individual benefits from the public good while not contributing to it. This tension goes by many names, including the “tragedy of the commons” or the “free-rider problem.”

Although researchers have long thought that the primary function of play was for skill practice and training, this socializing and trust-building function seems more fundamental. As Stuart Brown observes, “Cats deprived of play-fighting can hunt just fine. What they can’t do—what they never learn to do—is to socialize successfully. Cats and other social mammals such as rats will, if seriously deprived of opportunities for play, have an inability to clearly delineate friend from foe, miscue on social signaling, and either act excessively aggressive or retreat and not engage in more normal social patterns.”50

The fact that humans retain into adulthood the complex and sophisticated cognitive machinery required to play, and in fact continue to enjoy playing with others, is a reflection of the profound importance of trust in human affairs.

if we want to re-create the cognitive flexibility of a child, a transcranial magnet would do the trick: We can just zap the PFC into submission. Such devices, however, have only become available recently. They are also expensive, not very portable, and typically not welcome at parties. What we need is something really low tech. Something that effectively takes the PFC offline and makes us happy and relaxed, but only for a few hours or so. Something that can be made anywhere, out of almost anything, by anyone, and produced reasonably cheaply. Bonus points if it tastes good, can be easily paired with food, and leads to dancing and other forms of communal sociality. Alcohol, of course, fits these design specs to a T.

alcoholic inebriation is “biphasal.” The ascending phase, as blood alcohol levels rise, is characterized by stimulation and mild euphoria, as alcohol enhances the release of dopamine and serotonin. This is when alcohol mimics the effect of pure stimulants, like cocaine or MDMA. During this phase, alcohol also triggers the release of endorphins. You can think of it, in this regard, as something like a mild version of morphine, providing a pain-killing effect, enhancing overall mood, and decreasing anxiety.57 In its descending phase, as blood alcohol levels peak and then start to decline, alcohol has its depressant effect. In terms of inhibition of brain functioning, alcohol provides a depressant double-whammy. It enhances or exaggerates the activity of GABAA receptors, which function to inhibit neural activity, while simultaneously depressing the activity of glutamate receptors, which normally excite neural activity. So, when it comes to brain activity, alcohol simultaneously slams on the brakes and lets its foot off the accelerator. This neural screeching to a halt is what, especially at high blood alcohol levels, causes a sedative effect.58

It is also worth noting that there are various non-chemical practices that can produce cognitive effects that mimic alcoholic intoxication. For instance, extreme exercise can produce a “runner’s high” through stimulation of dopamine and downregulation of the PFC, as the overstressed body diverts resources away from the energy-hungry neocortex and toward more immediately necessary motor and circulation systems. The neuroscientist Arne Dietrich has argued that this combination seems to be responsible for the loss of sense of self and intense euphoria characteristic of athletic “peak experiences.”69 Various religious traditions have availed themselves of this trick. Sufi dancing, group singing and chanting, extended meditation in painful poses (cross-legged; kneeling in prayer), personal mortification (self-flagellation; piercing), or extreme breathing exercises can all provide a similar sort of high, boosting dopamine and endorphins while diverting energy away from the PFC.

The Greek pantheon includes two gods, Apollo and Dionysus, who personify the tension between self-control and abandon.71 Apollo, the sun god, represents rationality, order, and self-control. In art, the Apollonian mode is characterized by restraint and elegance, carefully designed balance. Apollo was worshipped by means of staid, formal offerings in designated temples. Dionysus is the god of wine, drunkenness, fertility, emotionality, and chaos. Dionysian art indulges in excess, ecstatic elevation, altered states. His worshippers famously included the maenads, wild women who would gather secretly at night in the woods for the original bacchanalia, alcohol- and drug-fueled parties rather like contemporary raves, only with a much darker edge, more nudity, and occasional cannibalism. Dionysus appeals to the more ancient, primitive regions of our brains, those dedicated to sex, emotions, movement, touch. Apollo finds his natural home in the prefrontal cortex.

The PFC is what makes adult humans typically function more like grim wolves than playful Labradors.

Intoxication helps us with the demands of our ecological niche, making it easier for us to be creative, coexist in close quarters with others, keep up our spirits in collective undertakings, and be more open to connecting and learning from others.

This is why alcohol use, despite its costs and the problems it brings in its wake, has not been eliminated by genetic evolution or cultural fiat. Whether literally or spiritually, from time to time, we need to get drunk. Apollo must be subordinated to Dionysus; the wolf needs to give way to the Labrador; the adult needs to cede her place to the child.

So, the story goes, sometime after mastering farming, humans also began to enjoy the benefits of beer, with similar processes around the world leading to grape, millet, rice, and maize-based alcoholic drinks. People finally had something tasty to pair with their bread and cheese. This is the standard account of the origin of alcohol production—that it’s an accident, an unintended consequence of the invention of agriculture. Around the 1950s, though, this story began to be questioned by proponents of various “beer before bread” theories.1 They pointed out that large-scale, likely alcohol-fueled feasting, which often brought together people from far-flung regions for days of music, dancing, rituals, drinking, and sacrifices, began well before settled agriculture. At Göbekli Tepe, a site in what is now modern-day Turkey we’ll talk about more below, hunter-gatherers convened regularly throughout the tenth to eighth millennia BCE to feast on gazelles, build circular structures, and erect enormous T-shaped limestone pillars carved with mysterious pictograms and animal forms—probably all while well-lubricated with beer.

across the ancient world, we see similar evidence that the first large gatherings of people, centered on feasting, ritual, and booze, happened long before anyone had come up with the idea of planting and harvesting crops.

One recent discovery found evidence of bread and/or beer making at a site in northeastern Jordan dated to 14,400 years ago, predating the emergence of agriculture by at least 4,000 years.2

The human mastery of fermentation into alcohol is so ancient that certain yeast strains associated with wine and sake show evidence of having been domesticated 12,000 years ago or more.5

All of this suggests that it is quite likely that the desire to get drunk or high gave rise to agriculture, rather than the other way around. Agriculture, of course, is the foundation of civilization. This means that our taste for liquid or smokable neurotoxins, the most convenient means for taking the PFC offline, may have been the catalyst for settled agricultural life.

By causing humans to become, at least temporarily, more creative, cultural, and communal—to live like social insects, despite our ape nature—intoxicants provided the spark that allowed us to form truly large-scale groups, domesticate increasing numbers of plants and animals, accumulate new technologies, and thereby create the sprawling civilizations that have made us the dominant mega-fauna on the planet. In other words, it is Dionysus, with his skinful of wine and his seductive panpipes, who is the founder of civilization; Apollo just came along for the ride.

So ancient are shamanistic religions that some claim they can be found even among other, extinct hominid lines. The so-called “flower burial” in a cave in northern Iraq, from approximately 60,000 years ago, contains the remains of a Neanderthal (Homo neanderthalensis) male who was described in early reports as a possible shaman, based on pollen traces suggesting that he had been laid to rest on a bed of flowers that included a wide range of medicinal and intoxicating drugs.19

Leo Tolstoy was an uncompromising hard-ass when it came to confronting reality. He therefore had a predictably dour view of intoxicant use. In his 1890 essay, “Why Do Men Stupefy Themselves?,” he declares that “the cause of the worldwide consumption of hashish, opium, wine and tobacco lies not in the taste, nor in any pleasure, recreation, or mirth they afford, but simply in man’s need to hide from himself the demands of conscience.” Ouch.

Book of Proverbs, “Give strong drink unto him that is ready to perish, and wine unto them that be of heavy hearts. Let him drink, and forget his poverty, and remember his misery no more.”26