The desire to find our tribe is universal. We like to know who we are and where we belong. This fascination has led to a thriving industry built on the marketing and sale of personality tests. These tests offer individuals — and, increasingly, employers — quick and easy insights that can be used to make some of life's biggest decisions. But most fail to stand up to scientific scrutiny. This week, we delve into the world of personality testing, and explore the many different ways we assess personality and potential — from the Chinese zodiac to Harry Potter houses to the Myers-Briggs test.