If you read the news, you might be left thinking that humans are a xenophobic and parochial species. If we actually look at the data, however, we see a very different picture: our species can be both very tolerant and very aggressive toward members of other communities. Why is that? How did humans come to be that way?
Rewinding from 2019 to two million years ago, Dr. Anne Pisor walks through the forces of natural selection that favored so much flexibility in human inter-group behavior. She then illustrates how we can see the flexibility in our inter-group behavior in 2019, focusing on how globalization, technology, and migration are changing between-community relationships in South America.