Until the 1950s, their remote and harsh location isolated the Asmat from other peoples. It was not until the mid-20th century that they came into regular contact with outsiders. Initially, the Asmat had a reputation as headhunters and cannibals, and were left undisturbed. In addition to this it has been reported that many Asmat men had long-term ritual sexual/friendship relationships (mbai) with other men.
In the early 1900s, several exploratory excursions with the goal of reaching the central mountain range passed through the Asmat area and gathered small numbers of zoological specimens and artifacts. These artifacts were taken to Europe where they generated much interest, and probably influenced modernist and surrealist Western artists such as Henri Matisse, Marc Chagall and Pablo Picasso. below are some Asmat examples including a canoe prow statue shield and spirit costume.


Catholic missionaries, were successful in persuading the Asmat to stop cannibalism and headhunting, while encouraging the continuation of other important cultural cycles and festivals such as shield and bisj ceremonies, which were incorporated into an adapted Catholic liturgy. Asmat was the launching point for an expedition in 1958 to 1959, and resulted in a book and documentary film, "The Sky Above, The Mud Below"
The Asmat Museum of Culture and Progress (AMCP) was established in the local town of Agats in 1973, to maintain local pride in Asmat cultural traditions. Each year in early October, the church sponsors a woodcarving competition and auction to recognize outstanding carvers.