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

by Edward Slingerland

The evolutionary anthropologist Ed Hagen and colleagues70 have similarly shown that when it comes to plant-based recreational drugs like cannabis or hallucinogens, the hijack theory, at least, is undermined by evidence that humans have biologically adapted to consuming them. 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. Most herbivores, being sensible, give plants like this a wide berth. However, some particularly stubborn ones—or those with a powerful taste for coke—develop countermeasures, evolving to produce enzymes that detoxify the toxicants.