“The president can’t have a conflict of interest,” Donald Trump told The New York Times in November. He appears to have meant that in the legal sense — the president isn’t bound by the same conflict-of-interest laws that loom over other executive branch officials and employees.

But that doesn’t mean the president’s interests can’t be in conflict. When he takes office Jan. 20, Trump will be tangled in a wide array of situations in which his personal connections and business coffers are pulling him in one direction while the interests of the American presidency and people pull him in another. For example, Trump is the president of a vineyard in Virginia that’s requesting foreign worker visas from the government he’ll soon lead. He’s also involved in an ongoing business partnership with the Philippines’ diplomatic trade envoy — a relationship that could predispose Trump to accepting deals that are more favorable to that country than he otherwise might. Once he’s in office, he will appoint some members of the labor board that could hear disputes related to his hotels.

Neither Trump nor his transition team replied to interview requests for this article, but his comments to the Times suggest that he genuinely believes he can be objective and put the country first, despite financial and social pressures to do otherwise.

Unfortunately, science says he’s probably wrong.

Numerous studies have shown how conflicts of interest affect human behavior, both in the real world and in laboratory settings. Most of these have been conducted in the context of the scientific and medical professions. For instance, we know pharmaceutical companies don’t have to pony up for luxurious vacations or hand over bags of unmarked bills in order to change doctors’ prescribing habits. Even a $20 meal — a high-end cheeseburger or a cheap steak — is associated with an increased rate of prescribing a particular treatment, according to a study published in August.

Although politicians have largely been left out of this research, experts say the studies of doctors and scientists can be extrapolated to politicians like Trump. And, they say, the research shows that conflicts of interest built on both finances and friendships are likely to affect decisions that Trump will face as president, even if he doesn’t believe they will, and even if he is no more aware of their impact than your doctor is aware of the link between Ruth’s Chris and Crestor.

There are three key findings that are particularly important to understanding the impact of conflicts of interest on politicians.

First: You can end up behaving in an ethically compromised way without being aware that you’re doing it. “The most robust phenomena that’s been demonstrated is that there’s a relationship between the funder of the study and the outcome of the research,” said David Resnik, a bioethicist and chair of the National Institute of Environmental Health Sciences’ Institutional Review Board. In other words, if a company funds a scientific study, the results are more likely to favor the company’s interests than if that study were funded by, say, government grants.

The reasons behind this are complicated, Resnik said, but only rarely involve overt malfeasance by the scientist. In some cases, the funder might simply choose to not publish unfavorable results or cut funding if it’s clear that a study isn’t going to turn out well for them. More insidiously, conflicts of interest seem to be able to create an unconscious bias that’s expressed in the experimental design and analysis. That’s in keeping with neuroscience data showing that favors and financial sponsorship alter recipients’ thinking, making them more prone to bias in favor of the gift-giver. That’s true even if the gift is cheap, or if it’s something intangible, like a favor.

That means President Trump could enter into a negotiation with the Philippines with intentions as pure as Jimmy Stewart’s Sen. Smith but still end up with a deal that reciprocates favors he’s received in the past or that feels more fair to him than it should because of longtime social bonds.

In his interview with the Times, Trump denied that this kind of thing would be a problem for him, but that’s contradicted by the second really robust empirical finding that science has come up with on conflicts of interest: “People vastly underestimate the impacts of conflicts of interest on their own behavior,” said George Loewenstein, a professor of economics and psychology at Carnegie Mellon University. “That’s pretty much incontrovertible.”

Take, for instance, a 2001 study that found that 61 percent of doctors surveyed thought pharmaceutical industry promotions didn’t affect their prescribing. But when the survey asked about their peers, only 16 percent believed other doctors to be unaffected by the literal free lunch. In a 2003 essay, Loewenstein noted that “it cannot both be true that most physicians are unbiased and that most other physicians are biased.”

There is evidence of the same phenomena happening among people who aren’t scientists or doctors — for example in laboratory experiments in which people were tasked with acting as agents advising business owners who were selling or buying a corporation. In these experiments, both buyers’ and sellers’ agents were aware that their estimates of a company’s worth were probably biased, but both also wildly underestimated the degree of that bias. The sellers’ agents, for instance, thought they were overvaluing the company by about $900,000. In reality, according to the assessments of outside experts, they had overvalued to the tune of $2.9 million.

These two phenomena work together. Imagine a situation in which subconscious bias in favor of his own business interests drives Trump’s appointments to the National Labor Relations Board and, simultaneously, he believes he is less conflicted and less corruptible than other politicians.

Although social science research has shaped the way professional organizations for doctors and scientists frame their conflict-of-interest and ethics rules, it hasn’t really been used to formulate conflict-of-interest rules for government officials and definitely not for the presidency, said Richard Painter, a professor of corporate law at the University of Minnesota and a former chief ethics lawyer for President George W. Bush.

Painter is concerned about Trump’s potential conflicts of interest and said laws should incorporate what we know from science. “There needs to be more effort to address underlying psychological biases,” he said.

But here we come to the third big finding from social science research on conflicts of interest: The rules and laws we set to combat them don’t necessarily work, and they can have unintended negative consequences.

Consider, for example, the idea of disclosure. Scientific journals typically require research papers to include information about the authors’ potential conflicts of interest, like whether their research is funded by anyone with a financial stake in the outcome. On the surface, that seems to be a pretty good idea. (Trump has tweeted that his business conflicts don’t matter because the public that voted for him already knew they existed — the disclosure was obvious.) But, Loewenstein said, “there’s all sorts of reasons why [disclosure] backfires and ends up benefiting the person with the conflict and leading them to be more biased.” That includes rebound effects, when experts whose conflicts have been disclosed feel free to offer more biased advice than they normally would because they feel their cards are on the table. “Disclosure is really for the birds, in my view,” Loewenstein said.

That isn’t the only place where attempts to whack a conflict-of-interest mole can result in the mashing of our own metaphorical hands. We can see evidence of this in politics. “My frustration with reforms is that they keep incentivizing more opaque structures,” said Lara Brown, interim director of the graduate school of political management at George Washington University. The 2002 Bipartisan Campaign Finance Reform Act (aka McCain-Feingold), for example, did away with so-called “soft money,” contributions to national parties that could get around legal donation limits by not being earmarked for any one candidate. Some big donors received access to politicians — a soft, fluffy pillow on a White House sleepover in exchange for soft money, in a famous instance. But banning that funding track also led to the rise of super PACs, committees that ostensibly operate independently from the candidates they support and that can raise unlimited amounts of money. The difference, Brown said, is that in the era of soft money, the parties had to publicly record where it was coming from. Super PACs don’t. The money is still being donated, but now it’s happening behind a wall of mist.

We are stuck with a lot of evidence showing that conflict of interest is a serious problem and really does affect behavior — and not a lot of evidence telling us how to fix it.

Loewenstein and Brown both favor eliminating conflicts of interest, rather than trying to manage them through tools like disclosure. “People have a really hard time playing two roles at one time,” Loewenstein said. So it’s better to just give them one.

For Trump, eliminating conflicts of interest would almost have to mean divestment, Brown told me, because of the size and scale of his business and because of how involved his children — who he has said will be his successors in running it — have been in his campaign and transition team. After all, Rex Tillerson, Trump’s nominee for secretary of state, recently cut his financial ties with Exxon Mobil, the company he used to lead. Doing that means that Tillerson is losing millions in stock value, bonuses and benefits and that some of his money will be held in a blind trust. (This is similar to what some ethicists, including Painter, have said Trump must do.) If Tillerson returns to the oil and gas industry in the next decade, he’ll lose it all. If you have to do all that to become secretary of state, Brown said, “one would think that the president is going to have to divest himself of all of those holdings within his Trump empire.”