The moral psychologist Jonathan Haidt has shown that the moral foundations that undergird the political beliefs of conservatives and liberals are different from one another––that liberals tend to care more about whether a policy crosses thresholds of fairness or harm, for example, while conservatives tend to care more about loyalty and purity.

For Matt Feinberg and Robb Willer, who study effective persuasion across ideological lines, one challenge the U.S. faces is that today’s Americans aren’t good at working with others toward shared ends if the reasons for pursuing them are different.

"There's this tricky difference between moral difference and the absence of morality,” Feinberg said Monday during a panel at the Aspen Ideas Festival, which is co-hosted by The Aspen Institute and The Atlantic. “A Pew Research poll about a year ago asked Republicans and Democrats about the other side,” he explained. “And they found that about 50 percent of Republicans and Democrats thought that the people on the other side were immoral or amoral, that they didn't have morality. It's easy when you're in your bubble to think yours is the only morality. It's natural to think that the way you think about morality is the way that everyone either does or should, or else there must be something wrong with them.”

But experiments that Feinberg and Willer have collaborated on suggest that the exercise of trying to persuade others by understanding and appealing to their moral beliefs and concerns can help divided constituencies see merit in the same policies, even when underlying motivations for doing so remain as divided as ever.

Bear in mind that you needn’t agree with any particular position being advocated in the examples we consider to see the general potential for cross-ideological cooperation. Military spending is one issue the professors studied. As they explained:

We wanted to see if we could get liberals to be more supportive of military spending. The traditional argument from a conservative standpoint is all about patriotism and authority/respect. The military is what unites us at home and gets us respect abroad. We didn't think that would be too persuasive…

To get liberals to be more supportive of military spending we were curious if we could reframe it in terms of more egalitarian values. So we made an argument emphasizing that it's through the military that you can level the playing field, especially for the poor and minorities in the United States who get the raw end of the stick. By paying for the military you create a stepping stone for minorities to work their way into the middle class and beyond. And that was much more persuasive for liberals.

Another question they studied concerned making English the official language of the United States, a traditionally conservative position. “So we tested a traditional argument about patriotism and unity against a new message reframed to agree with liberal moral values––that learning English was helpful to the integration of society; for upward mobility, people would achieve higher wages; and minorities, especially Latinos, could do better and be less likely to get discriminated against.” Liberals confronted with reasons to support the policy that appealed to their moral foundations were more likely to support official English.

The tactic works on conservatives, too.

As my colleague Olga Khazan, who moderated the Aspen session where the professors spoke, has reported, they have found that “conservatives were more likely to endorse environmental protections when researchers activated their concerns about purity, rather than the more liberal concern about harm: A picture of a forest covered in rotting garbage, in other words, performed better with Republicans than a forest of tree stumps.”

And with respect to health care, the professors explained:

We were trying to get conservatives to be more supportive of universal health care and the Affordable Care Act. What we did is to have two randomly assigned conditions, either you read the more traditional argument of why you should have universal health care, about equality, how everyone desserves this, it's a right. Or for the morally reframed one, we tried to frame it in terms of purity. This time we emphasized that having sick people around us can be disgusting and impure and contaminated. That was effective in getting conservatives to be more supportive both of the Affordable Care Act and universal health care in general.

Again, I am not advocating for or against any of the particular positions that the professors chose to persuade people towards in their experiments. Rather, I am observing that for every position that ought to be adopted (however one determines that), there are likely people to whom it would appeal for very different reasons, themselves grounded in very different attitudes toward moral foundations.

Insofar as we value both living together in harmony and adopting good policies, we ought to relish opportunities to work toward the same ends for different reasons.