When the Gang of Eight authoring the Senate immigration reform bill, which would be the first major overhaul since the 1980s, recently announced a new provision to create a “human wall” at the U.S.-Mexico border, tensions rose in D.C.

The move would double the number of U.S. Border Patrol agents and funnel more than $46 billion to border security in the Southwest. Since then, Arizona Sen. John McCain has said that the plans for a human wall might need to be tweaked, but an increase in border enforcement will continue to be central to the debate over this bill.

As deliberations continue, a new study for the American Sociological Review puts a new spin on the fundamental question of why there are so many (around 11 million) undocumented immigrants in the U.S. to begin with.

According to the new research, the danger of arrest and punishment at the border is not that big of a deterrent for many Mexicans considering whether to cross into the U.S. illegally. And as they weigh the decision, they have a lot more on their minds than just finding a better job. Many Americans assume that the decision to cross illegally is a purely economic one, since jobs in the U.S. often pay better. Yet values and social norms in the communities that Mexican immigrants come from may play a larger role in the decision to hop the border than previously realized. The study offers a gentle reminder—not to mention empirical evidence—that undocumented Mexican immigrants have the distinctly human trait of not being automatons.

“The view of would-be migrants as atomistic, utility-maximizing opportunists diverts our attention away from the complex and wide-ranging moral systems within which prospective migrants are embedded,” writes the study’s author, USC law professor and former Stanford research fellow, Emily Ryo.

Yet U.S. immigration policy in recent decades has been based largely on the premise that undocumented Mexican immigrants make decisions based solely on economics, Ryo says. Thus, the assumption has been that undocumented immigrants see any law as worth breaking—if it will help them earn a living. Yet a 2007 study shows that “incarceration rates for young men in the U.S. are the lowest for immigrants, especially for (first-generation) Mexicans, Salvadorans and Guatemalans—the groups that make up the bulk of the unauthorized population.” In other words, if these immigrants made decisions based solely on economics, they’d be breaking laws all over the place, even when they get to the U.S.—which they are not. Similarly, Ryo’s new work indicates that the premise that crossings are driven by purely economic factors just is not true.

Ryo found that in many communities across Michoacán, Morelos and Jalisco, when family or friends have attempted an illegal crossing before, subjects are three times more likely to attempt the journey themselves. An individual’s perception of the American justice system is also a big factor, though not in the way you might think: People who believe the system is unfair to darker-skinned immigrants are half as likely to have moral reservations about crossing illegally. Those who think the system is fair are 75 percent more likely to say they will not enter the U.S. illegally.

If Ryo’s research is accurate, U.S. policymakers could take a hint from it: Improving the reputation of our justice system could be one novel way to deter undocumented immigration. The more respect prospective immigrants have for the system, the less likely they are to try to break its rules.

The other suggestion that policymakers in Washington, D.C., might glean from Ryo’s work—and from what she says is a wider, growing body of research among academics—is that resources poured solely into apprehension at the border may not be the wisest allocation of tax dollars. (Last year, the U.S. government spent more on immigration enforcement than on all other main criminal federal law enforcement agencies combined.) U.S. investment in Mexican communities that aims to increase employment rates might be one way to deter the onslaught of attempted crossings—but not just because it may improve the economic situation in those areas. “It might make staying at home … a morally acceptable option for prospective migrants,” because it could improve international perception of the legitimacy of U.S. laws, Ryo says.

Piecing together intriguing data like Ryo’s is one thing, but applying it to policy and making it politically palatable is unlikely to happen any time soon.

Tay Wiles is the online editor for High Country News, the site from which this was cross-posted. The author is solely responsible for the content.