French police forces block Lies Hebbadj, who is wearing a full-face veil known as a niqab, from entering the court of justice in Nantes in August 2012 because she refused to show her face. France and Belgium are the only two countries in the world to ban the full-face veil in public. (Frank Perry/Getty Images)

A team of economists and political scientists — Claire Adida, David Laitin, and Marie-Anne Valfort — are about to publish their new book “Why Muslim Integration Fails in Christian-Heritage Societies.” The Monkey Cage has featured their research before, but this is clearly an important moment to delve into the book’s broader argument. The authors answered my questions via e-mail. A lightly edited transcript is below.

Your book begins with a look at discrimination against French Muslims in employment and hiring. What are the most important findings about this form of discrimination?

We show that Muslims are discriminated against in the French labor market, and it is because they are Muslims. Previous work has shown that discrimination exists against people who originate from Muslim-majority countries; but this work doesn’t isolate the source of discrimination. Is it Islamophobia or is it xenophobia? Our study, relying on a population of Senegalese immigrants to France that is both Christian and Muslim, and that is similar in all other regards, successfully isolates religious-based discrimination.

And some research that came after the book research shows the same phenomenon, even outside of this Senegalese population, correct?

That’s right. Between September 2013 and September 2014, Marie-Anne Valfort partnered with the Institut Montaigne to conduct the largest résumé experiment ever fielded, with over 6,000 résumés submitted to actual job openings in the French labor market. This experiment involved male and female candidates of Lebanese origin and still found significant anti-Muslim (as well as anti-Jewish) discrimination in France. While a Christian male applicant must on average submit 5 résumés to receive a call-back for an interview, an identical Jewish male applicant must submit 7, and an identical Muslim male applicant must submit 20.

There is a chapter on what you call “rational Islamophobia.” People might be surprised to hear Islamophobia described as “rational.” What is your argument here?

We think it’s critical to distinguish between “rational” and “legitimate.” We use the term rational in the way economists use it when they distinguish between what’s called “taste-based” and “rational” discrimination.

Taste-based discrimination means that employers discriminate against Muslims because they prefer not to interact with them, even if it means suffering from a lower-quality workforce. They are paying a price for their distaste, and need not hold any beliefs about the quality of Muslim applicants to justify their discrimination.

“Rational” discrimination, however, is based on beliefs: employers discriminate against Muslims because they believe that Muslims, on average, are less capable workers even if their paper qualifications are equal to non-Muslim applicants. Because it is based on beliefs, it is rational discrimination — although illegitimate and illegal .

But at the same time, you also see a lot of “taste-based” discrimination, correct?

Yes, indeed. Even when French people do not hold any particular beliefs about how Muslims behave, they discriminate against Muslims.

In our research, we organized a set of experimental games designed to observe French citizens with no recent history of immigration interacted with Senegalese Muslims and Christians. One of these is a trust game, a game in which both players (who have never met) can win a substantial prize if they trust one another. But in the way we set up the game, players can also betray the trust afforded them and keep all the winnings to themselves.

In play between the French and the Senegalese players, the French were less likely to repay the trust afforded them to the Senegalese Muslim players as compared to the Senegalese Christian players. This can only be due to distaste.

You talk about how these various forces constitute a “discriminatory equilibrium”? What does that concept mean?

Muslims exhibit cultural differences — such as more conservative views toward women and a higher degree of religiosity — that threaten (legitimately or not) their French hosts. The French, partly in response to this threat but also purely as a matter of taste, discriminate against Muslims. Facing no incentives to integrate, Muslims withdraw even more, thereby exacerbating the threats perceived by their French hosts.

This concept captures the fact that both parties act in a way that reinforces the status quo of failed Muslim integration, and that neither has incentive to change its behavior. Muslims experience taste-based discrimination on the part of their hosts, thus facing no incentives to try to integrate. The French hosts see a Muslim community in withdrawal, which confirms and reinforces their prior beliefs about an immigrant community that cannot or will not integrate.

Is the French case unique? Have other countries managed to integrate Muslims more successfully than France has?

France is not unique. We show that the discriminatory equilibrium exists in the United States and in Europe more broadly.

Using various surveys, we examined the experiences of Arab American Muslims and Arab American Christians in the Detroit area, as well as first- and second-generation Muslim and Christian immigrants to Europe from Muslim-majority countries, with a special focus on Bosnian Muslims and Catholics.

In both cases, we find that Muslims are less successful than Christians in the labor market and report higher levels of discrimination from host nationals. Alarmingly, these differences persist over time.

But the reason to focus primarily on France is because it has the largest Muslim community in Western Europe — approximately 7 percent of France’s population. This heightens the fear the French have about Muslims’ inability — what they see as refusal — to integrate into French society. Moreover, French “republican” myths — in which ethnicity is not formally recognized (and data not officially collected) — has allowed French society to ignore the levels of discrimination that their Muslim citizens experience.

The title of the book sounds pessimistic. Do you think there are any concrete steps that might help Muslims integrate into predominantly Christian countries?

We spent a long time reflecting on this, because none of us are pessimists by nature. So our book offers concrete steps for achieving a better integration outcome at the individual, societal, and macro levels. We believe that most of our efforts should focus on the societal level. Here are three examples that we elaborate in the book:

First, the job market. Here, we envision a set of diversity training programs that would highlight to recruiters their current discriminatory behavior, as well as the demonstrated benefits of diversity for a firm’s reputation and productivity. Muslims, for their part, will need to make some compromises in their cultural practices when at work or in school when worker safety or the esprit de corps of the workforce is at stake. Waiters in restaurants will need to serve wine even if they think it immoral to drink it; workers must obey orders from superiors no matter the gender of their superiors; and technicians should not work while fasting if fatigue is a threat to fellow workers.

Second, the educational system in France remains harmfully elitist: it leaves far more children behind than that of most other Western democracies. It has truly failed in attaining its goal of equality of opportunity. We offer suggestions for significant reforms at this level aimed at enhancing the integration experience of France’s immigrant communities.

Finally, Islamic representatives in France play an important moderating role, and this needs to be emphasized. Currently, the Ministry of the Interior estimates that only 10 percent of France’s 1,800 imams are trained in France. The French government must prioritize the training of imams in France and in French, in collaboration with the French Council of the Muslim Faith (CFCM).

The title of our book reflects the current state of Muslim integration in France and other Christian-heritage societies. For that reason, it sounds pessimistic. But a better integration outcome is not impossible. It will necessitate action on both sides of a growing cultural divide.