lichtrausch wrote:The full article appears to be behind a paywall. Which human populations experienced these changes?
Europeans are a mixture of ancient hunter-gatherers, farmers that came from Anatolia to Europe and the steppe pastoralists that came from the Pontic/Caspian region (they brought the dominant European R1a/R1b male haplogroups, the Kurgan people or Indo-European "Urvolk"). The latter two would be the ones that brought about the change.
When the persistence of overbite and overjet in a population is approximated by the prevalence of agriculturally produced food, we find that societies described as hunter-gatherers indeed have, on average, only about one-fourth the number of labiodentals exhibited by food-producing societies, after controlling for spatial and phylogenetic correlation. When the persistence is approximated by the increase in food-processing technology over the history of one well-researched language family, Indo-European, we likewise observe a steady increase of the reconstructed probability of labiodental sounds, from a median estimate of about 3% in the proto-language (6000 to 8000 years ago) to a presence of 76% in extant languages.