https://www.sciencedaily.com/releases/2015/09/150914220528.htm

“We wanted to test a new evolutionary theory in psychology called Social Baseline Theory which suggests that humans adapted to be close to other humans,” says Ms. Lougheed. “The idea is that individuals function at a relative deficit when they are farther away from people they trust.”

— I’ve been saying this for 30 years now… except that it is group-based, and individually modulated…