Blue Eye/Brown Eye is an experiment performed by Jane Elliot in 1968 on the day after Martin Luther King, Jr. was assassinated to demonstrate what prejudice was to her third grade class. The basic idea was to separate the class into two halves - those with blue eyes and those with brown. She then told them that the children with blue eyes were inherently inferior to the children with brown eyes - they were denied access to play equipment, they were told they were stupid, and they were not allowed to socialize with members of the 'superior group'. The next day the roles were reversed, with the blue-eyed children treated as better.

The idea behind the experiment was to show the children first hand what prejudice was like. In this it was a success: on days when students were part of the inferior group, they showed lower test scores, less enthusiasm, and more hostility towards activities in the classroom.

The experiment has since been repeated with dramatic results elsewhere, with both children and adults. There are of course some major ethical questions raised by the original experiment - particularly the concept of 'informed consent'.