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.

Experimental procedure

Participants Eighty-eight healthy Israeli-Jewish and Palestinian teenagers participated in the study, with equal number of Jews, Arabs, boys, and girls. Participants lived in rural and urban areas in the center of Israel. Participants of both groups diverged in their living communities (urban, rural) and religious commitment (religious, secular). [...] Adolescents were between 16 and 18 years (M = 16.54, SD = 0.77). Subjects were randomly assigned to experimental and control groups using computer-generated list of random numbers [...].

Dialogue intervention for youth growing in conflict zones We applied the Tools of Dialogue Intervention to groups of Israeli and Palestinian youth. [...] Four groups were conducted –two boys groups and two girls groups. [...] Sessions were held weekly for eight consecutive weeks and each lasted for 2 h. [...] Following the introduction, leaders introduced group discussion on the session topic [...] as well as activities, games, and guided imagery. Each session included opportunities for dyadic dialogues between participants from the two groups, as well as whole group interactions and group activities in which participants shared their family history, personal suffering related to the conflict, and the impact of the national conflict on their daily life. During the sessions we attempted to reduce tension through acquaintance and one-on-one interactions and increase empathy and perspective-taking, through the leaders' guidance and via the understanding that all youth share similar interests (e.g. sports, music), problems (with parents, teachers) and aspirations (future hopes). We also elicited empathy to the other side using role playing, songs, and videos. The intervention ended with two summary sessions in which youth expressed their “needs” from the other side, formulated practical suggestions for inter-group communication, described their personal experience in the group, and expressed future hopes at the personal and community levels. The last activity in the intervention was a metaphorical “gift giving” to the group. [...]

Pre-and post-intervention assessment Identical visits were conducted at baseline (T1) and after intervention or after 3 months for controls (T2), with a similar time-lag between T1 and T2 for the two groups. The control group did not receive any intervention and changes in study variables may be attributed to maturation or the T1 encounter. Each assessment included one-on-one interactions, hormonal collection, MEG, in-depth interview, and selfreports. To assure blind assessment, intervention leaders or assistants did not participate in data collection, coding, or analysis and all information was kept masked until the end of trial and data analysis stage. [...]

Dyadic interaction on a positive theme: Youth participated in one-onone dialogue with outgroup member for 7 min. Participants participated in a “fun day” paradigm developed and validated in our lab. [...]

Cortisol: Five saliva samples were collected at each assessment (T1 and T2), in order to evaluate the participants' overall cortisol production during the entire experiment. Saliva samples were collected [...] at baseline (10 min after arrival at the lab), and right after each empirical paradigm as follows: after interaction with ingroup and out-group members [...], after MEG scanning [...], and at recovery [...]. [...] Measurements were performed in duplicates according to the kit's instructions. In addition to the manufacture low and high controls [...]. Cortisol concentrations were calculated by using MatLab-7 according to relevant standard curves. [...]

Attitudes toward national conflict: Participants were interviewed individually on their attitudes toward the Israeli-Palestinian conflict, potential solution, and the possibility of national conflicts to ever be resolved. Belief in dialogue, the measure used here, addressed the degree to which adolescents believed that the conflict has the potential to be resolved and endorsed the solution of using an outside mediator is the way to reconciliation. [...]