" The alienating effects of wealth and modernity on the human experience start virtually at birth and never let up. Infants in hunter-gatherer societies are carried by their mothers as much as 90 percent of the time, which roughly corresponds to carrying rates among other primates. One can get an idea of how important this kind of touch is to primates from an infamous experiment conducted in the 1950s by a primatologist and psychologist named Harry Harlow. Baby rhesus monkeys were separated from their mothers and presented with the choice of two kinds of surrogates: a cuddly mother made out of terry cloth or an uninviting mother made out of wire mesh. The wire mesh mother, however, had a nipple that dispensed warm milk. The babies took their nourishment as quickly as possible and then rushed back to cling to the terry cloth mother, which had enough softness to provide the illusion of affection. Clearly, touch and closeness are vital to the health of baby primates—including humans. "

― Sebastian Junger , Tribe: On Homecoming and Belonging