According to An Administrative History of Vassar College 1861–2003, the first classes on the subject of mental processes were offered by the Philosophy Department under the name “Mental Philosophy” beginning in 1865. Psychological Science became a department in its own right in 1911 under the guidance of Margaret Floy Washburn, the first professor of Psychological Science at Vassar, the first woman to receive a Ph.D. in psychology in the U.S., and also the first woman in the U.S. to establish a psychological laboratory. Over the course of her Vassar career (1903–1937), Washburn mentored 177 students and oversaw 69 published studies.

While the scope of the Psychological Science Department has increased exponentially since Washburn’s time, the department’s emphasis remains on scientific research and the methods by which it is carried out. The major is structured in such a way as to require students to become familiar with a variety of subfields within the discipline while also allowing opportunities to achieve depth and to conduct research in particular subareas.