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.

Sample [...] Only Finnish-language schools were included in this study. The research design involved three pairs of upper-stage comprehensive schools mostly serving students 13±15 years of age. [...] Each pair of schools was matched according to ethnic density, i.e. the degree of diversity in the student population as measured by the percentage that are foreigners. [...] The assignment of schools to experimental or control conditions was random. A total of 1480 (746 male, 734 female) students, all of them ethnic Finns, participated in both baseline and follow-up survey in all six schools. The mean age of the students was 14.1 years.

Procedure [...] The process included baseline surveys, communication sessions in the experimental schools and follow-up surveys. At both surveys the questionnaires were distributed and administered by teachers in class and introduced without any explanation or reference to Helsinki University. [...] The intervention in the experimental schools included two types of modelling agents: (1) Same-age peers who shared (through printed material) their own stories of attitude change and (2) older models (university students) who expressed support for increasing tolerance of foreigners. In addition, the intervention included brief group discussions designed to influence group norms and perceptions of the social desirability of tolerance. The peer modelling was designed to change attitudes by portraying stories of attitude change. The intervention consisted of two communication sessions in classes of approximately 30 students, in which seven printed stories with a picture and first-person narrative described how peers had changed their attitudes toward foreigners through forming personal friendships with outgroup members. [...] Students who volunteered to provide a story were interviewed privately and seven stories were selected as role models for the printed material. Permission was obtained to photograph these students and present their story in written form to other pupils, both in their own school and in other schools. [...] After the stories had been printed, there were two sessions in each class of the first experimental school in which the stories were presented as good examples of positive intergroup contact. [...] In the first experimental school, the students who provided the stories were present in the classroom, but they were not asked to read or comment on their own stories. In the other two experimental schools, both experimental sessions included the distribution, reading and discussion of the printed stories which had been gathered from students in the first experimental school. In the classroom sessions students were randomly asked to read the stories aloud and comment upon them. Positive comments were praised and additional `testimony' of similar experiences encouraged, while negative comments were politely ignored. Disagreement or debate was not encouraged. During the discussions, the university students explicitly stated their own support for attitudes expressed by the students in the stories. Two sessions of approximately 50 minutes' duration, with three or four stories in each, were given at each experimental school. [...]

Measures The surveys were pencil-and-paper self-report forms in which students provided demographic information (age, gender) and answered questions in standard format by indicating extent of agreement with attitude statements on a five-point scale. The response options ranged from 1 (strongly agree) to 5 (strongly disagree). [...] To measure tolerance toward foreigners as a group (generalised attitudes), we selected a group of 17 items from various sources. These questions were designed to study a spectrum of prejudiced attitudes, opinions and behavioural intentions, with particular emphasis on attitudes toward Russians and `black' African immigrants as a group. [...]