Human beings are evolved creatures. Our lineage stretches back through the first humans to have evolved roughly 150,000 years ago, through their hominid ancestors, all the way back to the common ancestor we share with all other forms of life on the planet. Many of our traits are the historical results of evolution. This holds as much for psychological traits such as the visual system, emotions, and some behavior-producing mechanisms as for physical traits such as the heart, eye, or hand.

In a broad sense, evolutionary psychology covers any inquiry that uses this fact about our biological heritage to illuminate our human psychology. Historically, Charles Darwin himself pursued this kind of inquiry, as did such disparate figures as Herbert Spencer, John Dewey, and Sigmund Freud. Contemporary scientific fields such as human ethology and evolutionary anthropology are also instances of evolutionary psychology in the broad sense.

More commonly...