Edvard Alexander Westermarck (20 November 1862 – 3 September 1939) was a Finnish philosopher and sociologist. Among other subjects, he studied exogamy and the incest taboo.The phenomenon of reverse sexual imprinting (when two people live in close domestic proximity during the first few years in the life of either one, both are desensitized to sexual attraction), now known as the Westermarck effect, was first formally described by him in his book The History of Human Marriage (1891).