EVOLUTION: Why Humans Are Hard-Wired For Booze.

The earliest archaeological evidence suggests, based on chemical residues from pottery jars, that humans did not start fermenting honey, rice, and fruit to produce alcoholic beverages until 9,000 years ago.

But these fermented beverages were probably not our first exposure to alcohol, according to Dudley. Our preexisting taste for booze likely developed tens of millions of years ago in our primate ancestors, who survived mostly on fruits.

As fruit ripens, more alcohol is created by the yeasts. When a fruit starts to seriously rot, it can contain up to 8% ethanol, although most ripe fruit contains less than 1%.

Dudley’s theory suggests that the alcohol concentration of ripe fruit would have served a purpose for both the fruit-bearing plant and the primate. In tropical forests, fruit can be hard to track down. However, the scent of alcohol from ripe fruits travels long distances, and may have helped primates to find their next meal.

Being attracted to the scent of ethanol from ripe fruits would have been evolutionarily adaptive, enabling the primates to find fruit easier. It was also helpful to the plants, because the primates helped to disperse the seeds in the fruit.

But the gains of eating these alcoholic fruits doesn’t end there. Once digested, the theory goes, the alcohol would have stimulated feeding, encouraging the primates to “gobble up the food before anyone else got to it.” Humans know this feeling today as the aperitif effect, which you may have experienced if you’ve ever had a cocktail before a meal and found yourself hungry. Or craved cheese fries after a night out.

So, basically, the Taco Bell “Fourth Meal” phenomenon predates humanity.