Consider the classic hypothetical scenario: Your house is on fire and you can take only three things with you before the entire structure becomes engulfed in flames. What would you take? Laptops and external hard drives aside, people’s responses to this question differ wildly. This diversity results from people’s flexibility in ascribing unique value to objects ranging from a hand-scrawled note from a loved one to a threadbare t-shirt that others might consider worthless.

The critical quality that leads people to treat rookie cards like rosaries is that of the sacred, whereby an object becomes worthy of boundless reverence, commitment, and protection. As diverse as people are in ascribing sacred status to possessions, they are equally varied in which values they consider sacred, a diversity that can breed substantial conflict. The abortion debate, for example, often presents a divide between those who consider woman’s “right to choose” sacred versus those who consider a fetus’ “right to life” sacred.

A recent study in the journal for Judgment and Decision Making assessed how the Iranian nuclear defense program has become a sacred value and how this affects negotiation over Iranian disarmament, an issue of growing global concern. Just last month Iran defied the United Nations in beginning to enrich its uranium supply to bolster its nuclear program. The recent study on this topic by Morteza Dehghani and colleagues, offers two key insights. It demonstrates how a relatively recent issue, one that—unlike abortion—lacks any longstanding historical or religious significance, can become sacred. And it suggests, surprisingly, that offering material incentives in exchange for sacred values may backfire badly. The work is a reminder that sacred values are tremendously influential in disputes both international and interpersonal, but that our negotiating instincts can lead us away from common ground.

What truly distinguishes sacred values from secular ones is how people behave when asked to compromise them. When people are asked to trade their sacred values for values considered to be secular—what psychologist Philip Tetlock refers to as a “taboo tradeoff”—they exhibit moral outrage, express anger and disgust, become increasingly inflexible in negotiations, and display an insensitivity to a strict cost-benefit analysis of the exchange. What’s more, when people receive monetary offers for relinquishing a sacred value, they display a particularly striking irrationality. Not only are people unwilling to compromise sacred values for money—contrary to classic economic theory’s assumption that financial incentives motivate behavior—but the inclusion of money in an offer produces a backfire effect such that people become even less likely to give up their sacred values compared to when an offer does not include money. People consider trading sacred values for money so morally reprehensible that they recoil at such proposals.

Psychologist Jeremy Ginges and his colleagues identified this backfire effect in studies of the Israeli-Palestinian conflict in 2007. They interviewed both Israelis and Palestinians who possessed sacred values toward key issues such as ownership over disputed territories like the West Bank or the right of Palestinian refugees to return to villages they were forced to leave—these people viewed compromise on these issues completely unacceptable. Ginges and colleagues found that individuals offered a monetary payout to compromise their values expressed more moral outrage and were more supportive of violent opposition toward the other side. Opposition decreased, however, when the other side offered to compromise on a sacred value of its own, such as Israelis formerly renouncing their right to the West Bank or Palestinians formally recognizing Israel as a state. Ginges and Scott Atran found similar evidence of this backfire effect with Indonesian madrassah students, who expressed less willingness to compromise their belief in sharia, strict Islamic law, when offered a material incentive.

Common to both of these cases is that the research focused on values rooted in deep historical and religious traditions. However, Dehghani’s study demonstrates how this pattern of behavior has emerged for the Iranian Nuclear program, a relatively new development. In this study, the researchers asked 75 Iranians how they would feel about the possibility of Iran giving up its nuclear program, giving them four response options ranging from disarmament “definitely needs to happen” to disarmament “shouldn’t be done no matter how great the cost.” Those who chose the latter response option were classified as treating the issue of Iran’s nuclear program as a sacred value whereas those who chose other options were not.

After giving their opinions on Iran’s nuclear program, all participants were asked to consider one of two deals for Iranian disarmament. Half of the participants read about a deal in which the United States would reduce military aid to Israel in exchange for Iran giving up its military program. The other half of the participants read about a deal in which the United States would reduce aid to Israel and would pay Iran $40 billion. After considering the deal, all participants predicted how much the Iranian people would support the deal and how much anger they would feel toward the deal. In line with the Palestinian-Israeli and Indonesian studies, those who considered the nuclear program a sacred value expressed less support, and more anger, when the deal included money.

A more successful tack for negotiating over sacred values, as it turns out, is to simply use the right words. Whether discussing nuclear disarmament or reluctance to sell one’s lucky mug at a garage sale, using specific rhetorical strategies can make trade-offs seem less taboo and can facilitate conflict resolution. Tetlock and other psychologists have experimentally tested a number of strategies to demonstrate their effectiveness. One tactic is to describe tradeoffs in terms of “costs and benefits” and “analysis” rather than in terms of sacred values and money. This vague utilitarian language appears to mask the emotion-laden taboo nature of the exchange. Another strategy is to emphasize the dire, obligatory nature of the trade-off. For example, people are more willing to sell their body organs for medical transplants when told it is the only way to save lives because this framing posits the exchange as one sacred value for another. In an age where many of the most volatile conflicts stem from sacred causes, and politicians have questioned effectiveness of diplomacy, understanding how to best negotiate about these issues has never been more critical.

Are you a scientist? Have you recently read a peer-reviewed paper that you want to write about? Then contact Mind Matters co-editor Gareth Cook, a Pulitzer prize–winning journalist at the Boston Globe, where he edits the Sunday Ideas section. He can be reached at garethideas AT gmail.com