Psychology’s Prehistory As Nicholas Humphrey (1983) has observed, instead of being called Homo sapiens, we humans could more accurately be named Homo psychologicus. Assuredly, a vital part of what makes us human is that we are all innately amateur psychologists of a sort. That is, the very survival of early peoples was related to their ability to observe and under- stand what their conspecifics were feeling and intending to do. Even today, detecting and avoiding angry people, as well as quickly and intuitively understanding what a teammate expects us to do, or what another driver on the road is likely to do next, are common examples of how naturally we practice this psychology. Modern devel- opmental psychologists are especially interested in understanding how young children develop these skills that allow them to know what other persons are likely thinking and intending. This ability is called our theory of mind, and it has been a defining feature of humanity since our origins.