The Republican majority in the U.S. Congress led by House Speaker John Boehner, along with Israeli Prime Minister Benjamin Netanyahu and President Obama, are engaged in a vital debate on how to deal with the Iranian nuclear program: Should we threaten Iran with more sanctions, supposedly the only thing that has brought it to the table? The congressional majority and Netanyahu think so. The president argues that we should try to reach an agreement before we undermine the negotiation process with threats.

As a social scientist, I tried to come up with an objective way to determine who is right, independent of all the fears, suspicions, preconceptions and lack of information that inevitably cloud our judgment on such complex matters. So I designed an experiment.

I tossed a pair of coins 50 times each. To avoid pro-negotiation bias, I used American coins rather than coins from Iran or any country that currently has diplomatic relations with Iran. I scored two heads as conciliatory, one head and one tail as neutral, and two tails as threatening. When the coins were threatening, I told them I was cutting off their access to the international banking system. When they were neutral, I reserved judgment. When the coins were conciliatory, I agreed they could have 10,000 centrifuges.

Here are the results:

The coins’ threatening behavior forced me to impose sanctions a total of 12 times. When I demonstrated strength and determination by imposing sanctions, the coins came to the table 11 out of 12 times, 92 percent. But the one time they resisted, another round of sanctions put them under so much pressure that they had no choice but to comply.

The coins’ pretense of reform tricked me into making a generous concession 10 times. But they misinterpreted my willingness to compromise as weakness and reverted to aggressive behavior eight out of those 10 times! Twice their behavior seemed at least to remain neutral, but the coins were not sincere. They soon went back to their old ways. Once I had to reimpose sanctions immediately.

The fact that an inanimate object behaving randomly produces results so similar to how Boehner and Netanyahu perceive Iran’s actions should lead us to question their inference that Iran responds only to pressure. Did the coin respond only to pressure, or is something else at work?

One Israeli-American has the answer: Professor Daniel Kahneman of Princeton University, who was awarded the Nobel Prize in Economics for his studies of how people frame options and make decisions.

Kahneman shows that a statistical phenomenon called “regression toward the mean” systematically biases perceptions in favor of sanctions rather than incentives as means to change behavior, even when no emotional issues are involved, as with the coin. To put it simply, any extraordinary event tends to become more ordinary the next time it occurs for no reason other than chance. Episodes of very bad performance are usually followed by more average and therefore better performance. Episodes of excellent performance are also usually followed by more average and therefore worse performance.

Kahneman illustrated this with an incident that occurred when he was lecturing to flight instructors in the Israeli air force. Based on his extensive research, including many controlled experiments on how to change behavior, he argued that praise is more effective than punishment. One of the instructors contradicted him, saying that in his experience when he punished trainees for bad performance, they improved, but when he praised them for good performance, they became overconfident, and their performance deteriorated.

Israeli air force pilots, who might end up bombing Iran if the negotiations fail, have more in common with Iran than one might think. Iran and Israeli air force pilots both respond to sanctions and incentives, but the random variations that also affect their behavior tend to make us overestimate the effect of sanctions and underestimate the effect of incentives. Kahneman and his many collaborators have compiled masses of experimental evidence documenting how regression toward the mean biases judgment in favor of sanctions and against incentives in a range of situations.

Of course, my narrative about the coins’ behavior, while far more riveting than a list of results of coin tosses, infers intentions from behavior, though coins have no intentions. But if Iran or any hostile entity behaved as the coin did, many defense strategists would infer precisely those motivations from behavior that could result from many other factors, even chance. The tendency to explain negative behavior as the result of hostile intention rather than circumstance or other factors is called the “fundamental attribution error.” This error also blinds actors in situations of conflict to possibilities of cooperation.

The “illusion of transparency,” another finding of Kahnemann’s confirmed by laboratory experiments, reinforces the fundamental attribution error by discounting how our actions are perceived as threatening by others. We view the sanctions against Iran as a response to Iran’s hostile actions and intentions. Hard-liners in Iran view the sanctions as proof of our hostile intent — our determination to overthrow or weaken the Islamic Republic, regardless of its nuclear policies. Hence hard-liners on both sides see little reason to make concessions.

Most dangerous of all is what Kahneman calls the “positive illusion”: “biased overconfidence [that] raises the probability of violent conflict occurring and of deadlock in negotiations (when the parties overestimate their bargaining position or ability).” The belief that threatening more sanctions will force Iran to concede its core interests depends on precisely such an overestimation of our bargaining position. Our Iranian negotiating partners have told us it will end the talks, and the current political tensions in Tehran suggest they are not bluffing.

Even worse, the positive illusion effect makes Netanyahu and Boehner overconfident about the effectiveness of military strikes on Iran. Military strikes will not destroy all Iran’s installations. They will not destroy its knowledge, no matter how many Iranian scientists Israel assassinates. Military action will, however, destroy the coalition we have formed and assure that Iran will accelerate building its nuclear capacity with international support, even if after some delay. Military action would have consequences far worse than a weak deal or even containment of a nuclear Iran. Only illusions about its success keep it “on the table.”

Sanctions, along with many other external and internal factors, probably contributed to the mood of the Iranian people that made them decisively elect Hassan Rouhani president in 2013 and made it impossible for the establishment to deny him victory. Rouhani does not argue that Iran has no choice but to give in to pressure: instead he proposes a different vision of Iran’s relationship to the world, a belief in the potential for cooperation. He faces a powerful establishment that sees the United States with pretty much the same cognitive biases through which Boehner and Netanyahu view Iran.

That establishment will interpret more threats as proof that the United States will not remove sanctions whatever Iran does. It is in our interest to prove Rouhani right by giving him the chance to prove the hard-liners wrong. Otherwise, we might as well settle matters of life and death by flipping coins.

During a news conference Tuesday, Speaker of the House John Boehner addressed "stumbles" Republican lawmakers have run into so far in 2015 and objections to his invitation of Israeli Prime Minister Benjamin Netanyahu to speak before a joint session of Congress. (AP)