The Alien Nation
It has been said that before you judge someone you should walk a mile in their shoes, because then you will be a mile away and they won't be to run after you without potentially hurting their feet. Hodson et al designed an experiment that is based on this principle as an intervention to fight overt anti-homosexual biases.
Participants imagine that they have crash landed on a foreign planet. Humans exist on the alien planet but face similar constraints that are inadvertently experienced by homosexuals on ours. That's because the aliens on the planet look like humans but don't allow any PDA, live in same sex housing, and reproduce via artificial insemination. Basically, these aliens are total prudes. The participants get into groups and discuss strategies for how they would cope with such a situation.
By taking the perspective of a gay person in a non-explicit way, the participants were exposed to the side of out-group while their guard was down. Participants in the Alien Nation group had average "intergroup perspective-taking" scores on a post-study questionnaire of 4.03 out of 7, as compared to students that listened to educational lecture on homophobia who had scores of 3.07 out of 7. Moreover, Alien Nation group members had attitudes towards homosexuals scored at 75.87 out of 100 as compared to 64.26 out of 100, another positive and significant difference. You can see the effect sizes for yourselves, which remained steady when attitudes were retested after one week.
There are a number of ways to explain the efficacy of this study, but I think its main advantage is that it minimizes negative backlash. It is very easy to tune out a lecture or dismiss a speaker, but when participants are forced to take a perspective themselves, they have no choice but to engage. As virtual reality tech improves and as more creative forms of therapy are devised, we should try to make such attitude interventions both more active and less antagonistic.
(HT: BPSRD. Ref: Hodson et al, 2009, doi: 10.1016/j.jesp.2009.02.010)