" Human beings fear what they don’t understand. The unknown scares us. When we meet people who look or act in unfamiliar or strange ways, our initial response is to keep them at arm’s length. At times we make ourselves feel superior, smarter or more competent by dehumanizing or degrading those who are different. The roots of so many of our species’s ugliest behaviors—racism, ageism, misogyny, anti-Semitism, to name just a few—are in this basic brain-mediated response to perceived threat. We tend to fear what we do not understand, and fear can so easily twist into hate or even violence because it can suppress the rational parts of our brain. "

― Bruce D. Perry , The Boy Who Was Raised as a Dog: And Other Stories from a Child Psychiatrist's Notebook