Most museums are defined by the objects they display. A fine-arts museum exhibits paintings and sculptures. A history museum shows artifacts and documents. A science museum presents experiments.

But a growing number of museums today define themselves not by their collections but by the ideas they promote.

Take the Museum of Tolerance in Los Angeles. Founded after the Los Angeles riots in 1992, the museum promotes acceptance and peace across diverse cultures. That may be a noble cause with few obvious detractors, but it nonetheless represents a significant departure. Rather than present an authoritative vision of history, the museum is trying to shape its visitors’ behavior in the world beyond the gallery walls.

An offshoot of the Simon Wiesenthal Center, a Jewish human rights organization, the Museum of Tolerance has a large permanent exhibition examining the Holocaust. Yet it also features the Tolerancenter, with interactive displays encouraging visitors to set aside prejudices and become more liberal and accepting.