The fact that detectable traces were found in both individuals is a significant result.

The detection of arecoline in ancient dental tissue is described by Brumm as “as close to a smoking gun as we can get.” Arecoline is the compound that produces betel nut’s psychoactive effects.

Its presence in the teeth of Ice Age foragers on Sulawesi is direct chemical evidence that those people were exposed to areca nuts — that the nuts were in their mouths, releasing their active compounds into the surrounding tissues.

Third, pharmacological experiments.