From Popular Mechanics: Scientists say that while “domestication syndrome” has been theorized since the days of Charles Darwin, a new study is the first concrete data to show a link between group behaviors and physical signs of individual domestication. In the new paper, Princeton University researchers study the combination of a specific facial fur patch on marmosets with a vocal pattern they say corresponds to the patch. https://www.popularmechanics.com/science/animals/a34484237/monkeys-self-domestication-theory-experiment/

Related from The Daily Princetonian: U. study finds that monkeys may have self-domesticated like humans