The topic I chose for my oral presentation recently came back in the news, with the publication of the book The Drunken Monkey: Why We Drink and Abuse Alcohol by Dr. Robert Dudley, a professor of biology at the University of California Berkeley. The book goes into greater detail about the hypothesis I discussed in class about alcoholism stemming from the consumption of fermented fruit. The theory, which Dudley refers to as a the “Drunken monkey hypothesis,” proposes that our tendency to favor alcoholic drinks and become addicted to them stems from the fact that humans have developed a powerful sensory bias towards alcohol that relates it to nutritional reward. As detailed in an article in The Huffington Post by Dudley, titled “How Evolution Explains Why Humans Drink and Abuse Alcohol.” Primates would have eaten fruit living in more tropical climates, which would have exposed them to more rapidly ripening fruit that contains ethanol due to fermentation. The consumption of these fruits by primates and our subsequent evolution from them suggest that we may have developed a genetic adaptation that primes us to want to consume more of it. It makes sense that early primates would have been drawn to this as a food source in the first place – fruit flies were the first ones to figure out that the smell of alcohol indicated a good source of calories, and alcohol stimulates feeding in modern humans through the aperitif effect (apéritifs are alcoholic drinks that are served before meals to stimulate the appetite).
The drunken monkey hypothesis points toward an evolutionary mismatch in humans with our modern consumption of much higher levels and concentrations of alcohol, especially with the evolutionarily recent process of distillation. Animals in the wild do not get drunk, since fruit contain very low levels of alcohol. But it leaves humans with the evolutionary results of being drawn to alcoholic substances.