After further clinical training as a surgical resident at the Massachusetts General Hospital, service as a Peace Corps physician, and postdoctoral training at Harvard and University College London, he was appointed to the faculty at Washington University School of Medicine in 1973.

Although Purves was elected to the National Academy of Sciences in 1989 for his work on neural development and synaptic plasticity, his research during the last 15 years has sought to explain why we see and hear what we do, focusing on the visual perception of lightness, color, form, and motion, and the auditory perception of music and speech.

Purves was a surgical house officer at the Massachusetts General Hospital and a Peace Corps physician.

Purves joined the faculty of the Department of Physiology and Biophysics at the Washington University School of Medicine in 1971 and was there until 1990.

[citation needed] In 1990, Purves founded the Department of Neurobiology at Duke University where he did research on the cognitive neuroscience of visual and auditory perception.