The Essay - Darwin's Children - Episode 2

Writers explore some of the diverse fields to which Darwin's theories have been applied. Prof Judith Donath of MIT describes the link from Darwin to online social networks such as Facebook. Chimps affirm friendships through grooming each other; humans have evolved many different ways over the millennia, from clubs to Christmas cards. Is adding your name to a list on a public website the 21st century equivalent, and how might that change the shape of society?