*This is the fifteenth post in a series on Michael Livermore and Richard Revesz’s new book, Reviving Rationality: Saving Cost-Benefit Analysis for the Sake of the Environment and Our Health. For other posts in the series, click here.

About a decade ago, as a result of some unexpectedly icy roads between Illinois and Tennessee, my spouse and I were four hours late to Thanksgiving dinner. My aunt, who was hosting, had held dinner back. She had also (as we found out later) left her famous deviled eggs out on the counter waiting for us the whole time, incubating assiduously in the oven-warmed house. When we arrived—harried from a frightening drive—my aunt pushed us to start with some eggs. Guilty at our lateness, and hungry after too many hours subsisting on a bag of salted pretzel sticks, we each politely ate two—though they tasted a bit off. We all ate dinner. Then my spouse and I spent the rest of our visit sick with food poisoning.

My aunt insisted—with complete and wholehearted sincerity—that we must have gotten sick on the salted pretzel sticks, or on something else we had eaten the prior day. For her, the horrible idea that she could have poisoned us with her lovingly concocted canapés simply could not be true—and so it must not have been. She was not trying to deceive us by insisting that we could not have gotten sick from her deviled eggs: she fervently believed what she was saying. Indeed, for years afterwards she continued to offer us deviled eggs (on her special deviled egg serving tray) before Thanksgiving dinner—though we could never after bring ourselves to partake.

My aunt is not Donald Trump, and cost-benefit analysis is not a canapé. And yet the comparison may help illuminate the two puzzles I found myself pondering after reading Michael Livermore and Richard Revesz’s brilliant and provocative Reviving Rationality. Let’s begin with the eggs and save President Trump’s policies for dessert.

Consider, then, the real possibility that regulatory cost-benefit analysis is like deviled eggs: while it may be appropriate to many occasions where many people are involved, it is also unfortunately prone to spoilage when not handled carefully, or when asked to manage under unusual circumstances. If so, the procedural safeguards that Livermore & Revesz spend the last third of their book detailing are necessary as a kind of minimum sanitary baseline, and the high risk of spoilage suggests that those standards should be treated, followed, and audited as a form of regulatory “hygiene.” On this line of thinking, not only would agencies and the President do well to establish hygienic standards and audits, but courts should be particularly unforgiving at violations of those basic standards.

As with spoiled eggs, however, the impacts of the recent proliferation of spoiled analyses under the Trump administration—chronicled so compellingly in the first and second parts of Livermore & Revesz’s book—may have emotional as well as analytical impacts. In particular, it is worth worrying that once people have had an experience with spoilage, cost-benefit analysis may disgust them for some time. This may be especially true for those who already felt uneasy at the memory of early forms of cost-benefit analysis used in the Reagan administration, when modern standards had yet to be developed. This is one way to understand the arguably cooler embrace of cost-benefit analysis by the Biden administration than was characteristic of the Obama administration.

This is not a small point. Disgust is a complex emotion, easily transferred from object to object, with substantial power to shape people’s perceptions, preferences, and behavior. Increasingly, studies suggest that it can even influence our opinions of what is morally wrong and right. This phenomenon works even when the emotion of disgust is unrelated to the moral judgment in question: for example, inducing disgust (by having people smell something repellant, or associating a word with something disgusting) makes people more likely to condemn actions like accepting bribes.

Unfortunately, disgust is also strikingly difficult to cognitively override—so much so that psychologists have argued that the difficulty of inhibition is evidence of the emotion’s evolutionary roots. That’s not to say that it’s entirely hopeless to combat disgust—one recent study, for instance, found that having people eat ginger works as a kind of moral as well as physical anti-emetic, and makes people measurably less disgusted both by moderately gross images and by morally questionable behavior. (Interestingly it had no effect on people’s perceptions of extremely disgusting behavior, like eating one’s own dog; people still found those behaviors extremely disgusting.)

Eating ginger, however, is a markedly different remedy than re-establishing deliberative methodological standards in cost-benefit analysis—the remedy that Livermore & Revesz so intricately emphasized in that third part of their book. But even if reestablishing basic standards is critically important to preventing future spoilage, as suggested above, it may also do literally nothing to address the disgust many people feel at being offered (even hygienically-prepared) cost-benefit analysis on the equivalent of my aunt’s deviled egg serving tray.

So long as emotional and motivational responses inform policy, perhaps we would do well to consider emotional and motivational remedies alongside analytical ones. Yet it remains a legitimately open question how, exactly, we are supposed to do this. It seems silly, maybe even disrespectful, to prescribe serving ginger ale at policy meetings, or to write cost-benefit executive orders only after snacking on some candied Gin Gins. If remediation is difficult—as it is—perhaps it makes sense to start, as Livermore & Revesz have, with setting out analytical safeguards that can prevent future disgust. Like a restaurant that posts a banner bragging that it is “Now much cleaner!” after a health department closure, however, we should expect some entrenched hesitancy in re-embracing even so useful a policy tool as regulatory cost-benefit analysis. This hesitancy is likely to be emotional at least as much as it is deliberative, so that even such thoughtful deliberative arguments as Livermore & Revesz’s may struggle to penetrate it.

Which takes us back to the puzzle of finding emotional arguments for emotional objections. One emotional mitigator of disgust is familiarity. People find their own body odor less disgusting than other people’s, for instance, and mothers find the poop of their own babies less stinky. Sometimes this connection is dangerous: it may lead people to underestimate the risks of communicable diseases passed by loved ones, or the dangers of familiar pollution. But maybe there is opportunity here too: a psychological justification for emphasizing, as Livermore & Revesz periodically do, that cost-benefit analysis is a familiar baseline standard, a kind of old beloved friend now fallen on hard times. It feels strange to suggest that these passing characterizations may carry as much persuasive power as all of Livermore & Revesz’s knowledgeable accounts of the deliberative benefits of (appropriately safeguarded) cost-benefit procedures. But I do suspect they may.

Familiarity also generates other impacts beyond mitigation of disgust; it can also help to form the foundation for thicker networks of trust. Consider again my aunt’s deviled eggs. I have said that I trusted that my aunt was wholly sincere in her belief that she did not poison us—sincere, but biased. The bias in this case—the motivation to find any even unlikely alternative explanation to the upsetting conclusion that she had caused us harm–came from good intent, even if it led to implausible and arguably self-serving conclusions.

Indeed, psychological and behavioral research provides a slew of supportive explanations for how my aunt’s perceptions of the deviled egg scenario were likely skewed. In particular, motivated reasoning likely distorted her ability to see and process facts that were inconsistent with her strong preference not to have made us sick. (If anything, she likely held to the belief that she had not poisoned us more strongly because she cared so much for us!) The power of motivated cognition is such that people literally perceive and process the world differently depending upon what they wish to believe, remembering information that is consistent with their preferred positions better than that which is inconsistent; seeking out consistent but not inconsistent information; and accepting conclusions they prefer more readily than those that conflict with their pre-existing beliefs. In some cases, prior convictions actually strengthen with counter-evidence.

What has this to do with the future of cost-benefit analysis, or for that matter with the repeatedly and sometimes horrifically botched cost-benefit analyses of the Trump administration? Potentially a lot. In their book, Livermore & Revesz give a richly resourced account of the political history of cost-benefit analysis, including a detailed history of the partisan shift in support for cost-benefit analysis over time. They document Republican support eroding for cost-benefit analysis just as cost-benefit analysis increasingly quantifies the significant benefit of many expensive regulations, and they tell a narrative about that shift that is political and instrumental.

But motivated reasoning blurs the lines between what is instrumental and what is sincere, and creates challenges in distinguishing sincere bias from purposeful deceit. When the source of a harm or mistake is a loved one, it is easy to see even dangerous errors that flow from motivated cognition as good-hearted and sincere. Where trust has been undermined or where mistrust has been fostered, however—as inside our partisan politics—the same errors may appear pretextual, deceptive, or even evil. Was the Trump-era obsessive focus on regulatory costs—to the exclusion of regulatory benefits—a “charade,” as Livermore & Revesz contend, or was it the sincere product of motivated reasoning? Is Republican support for cost-benefit analysis eroding because Republicans seek to pretextually reject any form of reasoning that is inconsistent with their core ideological commitments—or because Republicans struggle (as all humans do) to actually perceive the virtue in anything that is inconsistent with their core ideological commitments? These questions are legitimately difficult to answer; both political and psychological accounts are consistent with the facts that Livermore & Revesz have so painstakingly gathered. And yet the implications are potentially different, and different predictions (and perhaps prescriptions) should follow.

In choosing between these accounts, I find myself noting what seems a potentially telling fact: that many of Livermore & Revesz’s rich examples stem from an area within the vast regulatory state that is peculiarly vulnerable to motivated reasoning: namely, environmental law. As Kenworthey Bilz and I have argued at length in our book on The Psychology of Environmental Law, environmental harms are distinctively hard for people to perceive, understand, and value, and thus particularly subject to influence by motivated cognition, as well as by other simplifying heuristics meant to impose sense where none is apparent. These cognitive, motivational, and emotional phenomena may be perfectly reasonable from an evolutionary perspective—but peculiarly distorting for individuals seeking to understand the types of diffuse, complex, and nonhuman harms addressed by modern environmental regulation. If we expected to see motivated reasoning on cost-benefit analysis skew any type of policy, we are wise to look to environmental policy for that distortion—and indeed, that is where Livermore & Revesz find it so often to be.

What if the Trump-era focus on costs and the shifting partisan landscape on cost-benefit analysis is best understood as (at least partly) psychological, rather than merely political? In that case, continued improvements in benefits quantification—while methodologically laudable—are likely to make it ever more cognitively and motivationally costly for Republicans to support regulatory cost-benefit analysis . . . even as they make it increasingly easy for Democrats to offer their support. Whether that motivational benefit is enough to overcome a feeling of general disgust with the entire enterprise of cost-benefit analysis remains an open question.

Arden Rowell is a Professor of Law at the University of Illinois, and the co-author of The Psychology of Environmental Law, A Guide to U.S. Environmental Law, and A Guide to EU Environmental Law.