The following is an excerpt of the intervention methodology. For more information, please see the full text of the article on the publisher's website or through your institution's library.

Subjects Approximately 400 students from two high schools responded to a slightly modified version of the California Ethaocentrism (E) Scale. In each school, 27 students were selected from each extreme and from the middle of the distribution of E scores, which closely approximated a Gaussian curve. [...]

Procedure Within each category of ethnocentrism, nine 5s were assigned at random to each of three experimental conditions, designated as film-discussion, film-alone, and control. This was done within schools, so that a total of 18 groups, or 162 5s, representing three degrees of ethnocentrism participated in the experiment. The film-discussion groups first viewed the film "The High Wall," which treats group prejudice as a communicable disease and traces its origins in the family and community. The members of these groups, representing low, high, and intermediate degrees of ethnocentric disposition, were given thirty minutes in which to discuss the film and related issues. [...] At the conclusion of the discussion, the 5s again answered the E scale. Members of the film-alone groups viewed the film Miss Rowenetta Allen. They again filled out the E scale upon conclusion of the film showing. The control groups responded to the E scale at the same times as the experimental groups but without any intervening exposure to either the film or a discussion. In order to determine the amount of learning of film content by the 5s, a 33-item multiple-choice Information test covering factual material in the film was devised through pretesting and item-analysis. [...] This test was administered to each of the experimental groups (film-discussion and film-alone) immediately after the second administration of the E scale, following presentation of the film. Both the E scale and the Information test were readministered a final time one month after the film showing in order to determine retention of information and stability of attitude change during this interval. [...]