Sucking an intact areca nut releases enough arecoline to trigger responses in the relevant human brain receptors.

The ancient foragers who were holding these nuts in their mouths were getting a real pharmacological effect.

Not as intense as the modern processed quid, but real.

“But our team conducted experiments in which we soaked betel nuts in artificial saliva and tested the resulting broths against a panel of cloned human receptors expressed in frog egg cells, including specialized proteins that act as molecular switches, regulating neural activity,” Brumm said in the Griffith University press release announcing the findings.

The three lines of evidence together — the distinctive dental wear, the chemical detection of arecoline, and the experimental demonstration of pharmacological activity from unprocessed nuts — constitute a convergent case that the paper’s title states directly: betel nut sucking is the earliest recorded evidence for the habitual use of a neuroactive plant drug.