Us and Them

Perceptions, memories, fears, hopes and wants are all blended by your mind to create a map of reality. One of the most important parts of that map is identity: your sense of who belongs where, in a world made up of races, ethnic groups, nations, religions, cultures, political parties, and countless other categories of person. But how does the mind come up with these labels? How does it sort their overlapping claims -- the demands of being, at the same time, for instance, a Muslim, an American, a ``soccer mom'' and a Democrat? How does it decide which labels are for fun, like ``Red Sox fan,'' and which labels are serious (like ``Red State voter''). Why can the same religious or political identity mean life or death in one place, but count for little in another? And, most of all, why do people the world over care so much about these groupings? Why are we willing to kill, or to die, for a nation, a religion, or a football team? In this award-winning book, David Berreby describes how 21st-century science is addressing these age-old questions. Us and Them links neuroscience, social psychology, anthropology and other fields to show how recent research has altered our understanding of humanity's ``tribal mind.'' From the medical effects of stress (which link tribal feelings to hormone levels and risk of heart attacks) to the rhetoric of politics (where the same few images have been used across centuries to trigger ``Us-versus-Them'' responses), our perceptions of group identity affect every part of our lives. Science, Berreby argues, shows how this part of human nature is both surprisingly important and surprisingly misunderstood.

Beyond its central premise, the book can be read through the connected lenses of Philosophy, Mental Health. Those themes offer useful points of attention as the characters, ideas, or world develop, especially where the book complicates the expectations of its primary category.