And yet the behavior continued.

That persistence in the face of severe dental damage is itself evidence of habituation or addiction: the substance was driving continued use despite serious harm.

What Arecoline Does In The Brain

Understanding why ancient foragers would have sought out the effects of betel nut requires understanding what arecoline does.

Arecoline is a naturally occurring alkaloid — a nitrogen-containing compound produced by plants, often as a defense against herbivores, that happens to have effects on animal nervous systems.

The plant alkaloids that humans have used for their psychoactive effects across history form a large and chemically diverse group: caffeine in coffee and tea, nicotine in tobacco, cocaine in the coca plant, morphine in the opium poppy, and many others.