A long glittering history buoys the idea that science is best based on experience. This idea is what inspires historians to claim modern psychology was born in the laboratories of the late 1800s. The very word empirical means ‘based on experience’, and it was the introduction of rigorous empirical methods that is most widely held to have delivered psychology from the primeval ooze of armchair speculation. But over time, as a direct consequence of psychology's success, the uses of the word experience have multiplied. Like any other empirical science, the word's first meaning was that psychologists' findings should be based on experience in the form of carefully collected first-hand evidence which, given the same circumstances, we could all ourselves experience and confirm. But experience is not just the foundation of psychology's method. It is also the main object of psychological research. Just as rocks and fossils are what geologists study, experience is what psychologists study. Their investigations cover everything from the parameters of pattern recognition and how rats' learn from electric shocks to the cognitive basis for visual illusions and why new mothers get depressed.