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.

Procedure [...]

First, participants undertook an imagination task, in which they were asked to read two hypothetical scenarios, one involving an interaction with an ingroup majority member and one involving an interaction with an outgroup minority member. After reading the first scenario, participants were provided with the intervention, marital interactions, or healthy eating material. Participants then completed measures of potential confounding variables and manipulation check items, followed by dependent measures: demand and resource appraisals, anxiety expectancy, and avoidance. After these measures, participants were asked to read the second hypothetical interaction scenario. Participants were then asked to complete the same manipulation check items and dependent measures, but this time with respect to the interaction partner indicated in the second scenario. [...]

Materials
Hypothetical interaction task
Each participant read two scenarios describing hypothetical interactions, one with an ingroup majority partner and one with an outgroup minority partner.

In the first scenario, participants read the following:

[TEXT STIMULI]

Participants then read about either a gender-matched ingroup majority partner or an outgroup minority partner:

[TEXT STIMULI]

Finally, the discussion topic of the scenario was introduced:

[TEXT STIMULI]

The second scenario was same as the first except that it was framed as the return-leg of the interstate train trip: “You are now traveling back home alone on your return interstate train and you end up sitting next to the following individual … ” The partner order was counterbalanced between participants: If the partner was an ingroup majority member in the first-leg of the trip, he or she was an outgroup minority member in the return-leg of the trip, and vice-versa.[...]

Intervention and control materials
Participants received information about “evidence-based strategies and techniques” for intergroup interactions (intervention condition), marital relations (active control), or healthy eating (passive control). The intervention condition included strategies and techniques that could be used by majority group members to improve intergroup interactions with a minority group member [...] Specifically, these strategies and techniques were thinking about similarities one has with one’s interaction partner [...], acknowledging partner race or group identity in discussion [...], approaching the interaction as an opportunity to have an enjoyable intercultural dialogue [...], and thinking about positive personal intergroup interaction experiences from the past [...]. Similarly, the information provided in the marital relations material [...] and healthy eating material [...] included strategies and techniques drawn from the literature that were aimed at fulfilling their respective goals. For example, the marital relations material included strategies such as creating fairness in housework [...], whereas the healthy eating material included strategies such as choosing good carbohydrates instead of complete abstention from them [...]. The materials were matched to include four guidelines, and each of the guidelines included an explanatory paragraph outlining its rationale and cited a study that supported it. The number of words in each material ranged between 540 and 591 (not including the references and title).

Potential confounding variables
The 20-item positive and negative affect schedule [...] was administered to participants to examine if there was a significant difference between positive and negative affect aroused by reading the intervention and control materials [...]. Further, to examine whether there was a significant difference between the materials in how interesting they were perceived to be, participants were asked to indicate “how interesting [entertaining, boring] did you find the information you just read?” on a 7-point scale (1 = very slightly or not at all, 7 = extremely)[...].

Manipulation check
Participants were asked to indicate on a 7-point scale how relevant, applicable, and helpful the guidelines they read in the intervention and control materials would be for their interaction with their ingroup majority or outgroup minority partner in each of the hypothetical scenarios (e.g., “how helpful do you think these techniques and strategies would be for you in your interaction with Fatima [Emily] given in the scenario?” 1 = not at all helpful, 7 = extremely helpful).

Threat appraisals
[...] demand appraisals was assessed by “I would expect this discussion to be a negative experience for me [to result in negative outcomes, to have a negative impact on me, to get heated, to turn into an argument],” and resource appraisals was assessed by “I would think I can handle the demands of the discussion [can contribute to the discussion as much as my partner, have a sense of control over the discussion, have enough knowledge to have a good discussion]” and “My partner has control over the discussion” [...]. From these measures a threat appraisal ratio (demand/resource) was created to examine the degree to which participants appraised the interaction as a threat in the context of their perceived ability to cope, as is common practice in the stress and coping literature [...] All items were rated on 7-point scales (1 = strongly disagree, 7 = strongly agree).

Anxiety expectancy
Adapted from frequently used items to measure intergroup anxiety [...], we measured how anxious participants expected to feel in the interaction using 14 items (e.g., “How stressed [worried, uneasy, nervous, etc.] would you expect you would feel in the discussion?” 1 = not at all, 7 = extremely; [...]).

Avoidance
Desire to avoid interaction was measured using five items adapted from Plant and Devine ([...] e.g., “I would rather not have this discussion,” 1 = strongly disagree, 7 = strongly agree[...]).