Immigration Doesn't Necessarily Reduce Social Cohesion and Trust

(Bloomberg View) -- Immigration opponents often struggle to come up with a good rationale for keeping people out of the country. With illegal immigration having essentially halted a decade ago, and with low-skilled legal immigration having tapered off as well, the traditional justifications have evaporated.

Undeterred, “restrictionists” have found another reason to reject hard-working, enterprising newcomers. In a recent op-ed, New York Times columnist Ross Douthat claimed that “as mass immigration increases diversity, it reduces social cohesion and civic trust.” This argument is gaining popularity, but it's deeply flawed and should not be guiding our thinking.

The idea that diversity decreases trust has an intuitive appeal to many who note, as my colleague Megan McArdle points out, that the high “cohesion of mid-century America coincided with a trough in the foreign population.” There's some serious research behind it as well. About a decade ago, celebrated sociologist Robert Putnam found evidence that:

In the short run … immigration and ethnic diversity tend to reduce social solidarity and social capital … In ethnically diverse [American] neighbourhoods residents of all races tend to ‘hunker down.' Trust (even of one's own race) is lower, altruism and community cooperation rarer, friends fewer.

Putnam isn't alone in his finding -- studies in Denmark, the United Kingdom, the Netherlands, and Europe have found similar results.

But this doesn't mean that it's a scientific fact that diversity decreases trust. There are plenty of studies that don't support Putnam's conclusion -- or even find the opposite. For example, another study in the UK found no correlation between diversity and trust, while a third found that the negative relationship disappears after controlling for economic variables. Another Europe-wide study found no correlation, while yet another found that diversity is actually associated with a long-term increase in trust.

A casual look at international survey measures will show that -- as McArdle notes -- ethnic homogeneity is no guarantee of a trusting society. Among rich countries, Scandinavia is the most trusting region, but diverse, immigrant-friendly places like Canada, Australia, New Zealand and Singapore actually score higher than homogeneous, low-immigration countries like South Korea, Russia, Japan and Poland:

What's more, even if diversity does decrease trust, the effect might not be that strong. Economist Bryan Caplan examined Putnam's research and found that even if the sociologist's numbers are completely correct, huge changes in diversity would reduce measures of trust only by a few percent.

An economist would also note that aside from simply asking people survey questions, researchers should look at how people actually behave. Ethnic diversity in Southern California has been linked to lower crime and higher home values. Studies reliably find that immigration reduces crime in the U.S., and this also appears to be true in Canada. Meanwhile, recent evidence on migration patterns show that Americans have tended to move to diverse neighborhoods since around 1990 -- voting with their feet rather than their survey answers.

Finally, it's important to note that there is more than one kind of social trust. Putnam measured what he called a “hunkering” effect -- how much contact people have with their neighbors. Though neighborliness is certainly important, there are other kinds of trust that could be even more important -- for example, trust among people of different ethnic groups.

There's a theory that prolonged, positive contact with people of other races reduces racial tensions. This “contact hypothesis” has plenty of support in the literature -- studies show that having college dorm-mates of a different race, or serving in an integrated military, reduces discrimination. This suggests that over the long term, diverse neighborhoods will have a positive impact on society-wide trust. A recent survey of 90 papers found:

People in ethnically heterogeneous environments are less likely to trust their neighbors or to have contact with them. However, this [effect] does not spill over to generalized trust, to informal help and voluntary work, or to other forms of prosocial behavior and attitudes … Rather, heterogeneity is positively related to interethnic contact and (consequently) to interethnic trust.

In other words, while an increase in diversity might initially cause people to avoid interacting with their strange new neighbors, over the long term it makes them realize that people of other races aren't so scary after all.

So people who go around claiming that diversity decreases trust, as if this is some sort of established scientific fact, are badly mistaken. There's plenty of evidence pointing in the other direction.

What's more, changing U.S. immigration policy based on the theory that diversity decreases trust is a bit crazy. The United States is already a very diverse nation -- less than half of the kids born in the country are white. If restrictionists think that racially engineering the U.S. population to be a few percent whiter would generate any kind of meaningful increase in social trust, they should think again. The U.S. will either succeed as a multi-racial nation, or it won't succeed at all.

“Successful immigrant societies,” Putnam himself writes, “have overcome [ethnic] fragmentation by creating new, cross-cutting forms of social solidarity and more encompassing identities.” This -- not racial engineering, but unity in diversity -- is the way forward for the U.S.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.

Noah Smith is a Bloomberg View columnist. He was an assistant professor of finance at Stony Brook University, and he blogs at Noahpinion.

To contact the author of this story: Noah Smith at nsmith150@bloomberg.net.

To contact the editor responsible for this story: Mark Whitehouse at mwhitehouse1@bloomberg.net.

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