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.

STUDY 1: MEASURED ALIGNMENT WITH GWC

The foremost goal of this study was to establish a bi-polar scale of alignment with GWC, composed of both identifying and rejective responses. [...]

Participants [...] Of the 291 individuals who gave informed consent, 44 indicated they were not Jewish-Israelis, and 42 did not complete the questionnaire, leaving a final sample of 205 (64.9% women; age: M= 32.97, SD= 10.4) Jewish-Israelis. The sample was varied in terms of religiosity (M= 3.28, SD= 2.2, on a 1–7 scale; see succeeding text) and political leanings (M = 4.65, SD= 1.43 [...]). [...]

Materials (All Administered in Hebrew, Throughout)

Religiosity. Three items were used to measure the level of religiosity; these included observance of traditional Jewish customs, adherence to religious roles, and self-labeling of secularism versus religious observant. Responses were given on a 1 to 7 scale [...].

Leftist Political Leaning. Three items were used to measure participants’ political orientations as it related to issues of economic, social, and security/foreign relation policies. Responses were given on a 1 to 7 scale [...].

Alignment with GWC Questionnaire. This composite 18-item measure included the Attachment Measure of Identification with Groups, combined with four novel items directly tapping cultural affiliation [...]. Six additional items tapped rejective responses towards GWC and were included in the measure after their coding was reversed. These included two items probing value opposition and four new items tapping the theme of contaminating cultural influences [...]. Responses were given on a 1 to 7 scale [...].

Israeli Ingroup Glorification. This eight-item measure [...] taps perceptions that Israel is superior to any comparable social group [...] as well as uncritical deference to this ingroup’s dictates [...]. Responses were given on a 1 to 7 scale [...].

PVD Measure. Participants were asked to indicate for each of the 10-item abbreviation of the Schwartz Value Survey [...], its descriptiveness of a prototypical Arab, of Westerner, and of themselves, on a 1 to 5 scale. [...]

Procedure [...] Participants were first asked several demographic questions including the measures of religiosity and political leaning and the measures of Israeli ingroup glorification and alignment with GWC (items presented in randomized order). Participants were next given the PVD measure (order of targets was randomized). [...]

STUDY 2: MANIPULATED IDENTITY REACTIONS TOWARDS GWC

The following studies were designed to further investigate the reasoning presented earlier while addressing some of the limitations of Study 1. [...]

Participants [...] After exclusion of seven participants who indicated they were not Jewish-Israelis, a final sample of 131 was employed (79.7% women). [...] Similarly to the previous sample, participants were not very religious (M= 2.99, SD= 1.49; all on 1 to 7 scales; see succeeding text) and leaned towards the political left (M= 4.35, SD= 1.13).

Materials

The same measures as those detailed in Study 1 were used for Religiosity, [...] Leftist Political Leaning, [...] and Alignment with GWC Questionnaire [...].

GWC Identity Primes. Participants were asked to [Verbal Stimulus A] in the GWC identification or rejection prime conditions, respectively.

PVD Measure. Because of a few comments made about clarity of PVD items in Study 1, the Portrait Value Questionnaire was employed instead. This questionnaire comprises 21 written descriptions of individuals who personify different values [...]. Participants were asked to indicate the degree of similarity between the described individual and the prototypical Arab-Israeli, Westerner, and of themselves, on a 1 to 5 scale. [...]

Denigration of Arab Culture. This short measure was developed to tap perceptions that Arab culture is inherently morally flawed [...] and underdeveloped [...]. [...] Responses were given on a 1 to 7 scale [...].

Desire for Social Distance. Participants were asked to indicate their un/willingness for social contact (on a 1 to 7 scale) with an Arab-Israeli, in reference to a series of seven statements ranging from occasional social interactions to having that person as a close personal friend. [...]

Anti-gay Prejudice. Four items, which were judged to be relevant to Israelis prejudices against gay people, were adapted from the “Attitudes towards Homosexuality” scale. [...]

Procedure [...] After signing into the system for credit, participants gave their informed consent and were transferred to the study site, where they anonymously answered demographic questions, including measures of religiosity and political leaning, and the baseline measure of GWC alignment. [...] Participants were next randomly assigned to a GWC prime condition, after which they were given the PVD measure and desire for social distance (several targets were presented in randomized order) and the measure of anti-gay prejudice. [...]

STUDY 3: WAR-TIME EFFECTS OF MANIPULATED IDENTITY REACTIONS TOWARDS GWC

Study 3 aimed to expand Study 2’s findings, at a time of extreme intergroup tension, while also including an empty control condition. During 50 days in the summer of 2014, Israel went on “Operation Protective Edge” against Hamas militants in the Palestinian-controlled Gaza strip. By the time of the cease-fire (26 August), fatalities rose to 72 in Israel and 2131 in Gaza. Compared with the previous rounds of conflict in recent decades, the 2014 war was unique in the scope of its effects on civilians: a majority of Israel’s population were under constant bombardment of mortar and rocket fire. [...]

Participants [...] Eleven out of the 89 submitted responses (12.36%) were excluded because of an invalid response to the assigned experimental condition [...], yielding a final sample of 78 Jewish-Israelis. The majority of respondents was women (n= 58) and held post-secondary degrees (n= 68). This sample was politically diverse (M= 4.32, SD= 1.43) and of diverse ages (M = 35.17, SD= 11.85).

Materials (All Responses were Given on 1 to 7 Scales)

Leftist Political Leaning. A single item asked participants to indicate their political leaning, on a scale anchored by 1 =extreme right and 7 =extreme left. [...]

Alignment with GWC Questionnaire. The same questionnaire was employed again [...].

GWC Identity Primes. In addition to the two primes described in Study 2, a control condition was included. Participants in this condition were asked to write a short essay articulating their opinion on an unrelated social issue [...].

Desire to Separate from the Palestinian People. Five items (one reversely coded) were composed to measure this desire [...].

Anti-gay Prejudice. [...] These five items included the three most socially contentious issues [...]: same-sex marriage and gay adoption rights, and two items probing attitudes towards the summer influx of gay tourists into Israel. [...]

Willingness to Make a Humanitarian Donation. Employing a “Windfall Expenditures” paradigm, participants were ask to “imagine that you just received a sudden windfall of NIS 100 000 which you have to spend. What would you do with the money?” Options included “Go on a lavish vacation to get away from this war” (Escape); “Help people who are close to me to get through these hard times” (Benevolent Help); “Donate the money to help Israeli civilians who have been affected by the war” (Ingroup Donation); and “Donate the money to help Palestinian civilians who have been affected by the war” (Humanitarian Donation). [...]

Procedure [...] This introductory page was accessed 147 times, but only 89 responses were submitted (60.5%), perhaps because of the request to commit to participation in the study’s second phase. After informed consent was given, participants were asked to answer a limited battery of questionnaires related to Israel’s military and diplomatic actions, general perceptions of Palestinian desire for a peaceful resolution of conflicts (12 items not detailed here), and the alignment with GWC questionnaire. Participants were then randomly assigned to a prime condition, after which they went on to answer more questions, including all remaining Likert measures. Lastly, participants were asked to answer a few demographic items, which included sex, nationality, age, educational attainment, and political leaning. On that page, participants were presented with the Windfall Expenditure measure, introduced as a “one last question.” [...]