The origins of personality testing date back to the 18th and 19th centuries, when personality was assessed through phrenology, the measurement of the human skull, and physiognomy, which assessed personality based on a person's outer appearances. These early pseudoscientific techniques were eventually replaced with more empirical methods in the 20th century. One of the earliest modern personality tests was the Woolworth Personality Data Sheet, a self-report inventory developed for World War I and used for the psychiatric screening of new draftees.