European paintings show a rise in trustworthiness

Building on recent advances in social cognition, we design an algorithm to automatically generate trustworthiness evaluations for the facial action units (smile, eye brows, etc.) of European portraits in large historical databases. Our results show that trustworthiness in portraits increased over the period 1500–2000 paralleling the decline of interpersonal violence and the rise of democratic values observed in Western Europe. Further analyses suggest that this rise of trustworthiness displays is associated with increased living standards.

That is from a new paper by Lou Safra, et.al. in Nature.  Scroll down a few pages for some good photos, basically the people in the paintings look less pissed off over time.  Via Lionel Page.