There’s a whole lot of cheating going on. More than 60 percent of college undergraduates, and more than 40 percent of graduate students, admit to cheating in some way on their written work, according to a national survey by Clemson University’s International Center for Academic Integrity. Now one graduate student has come up with a reason for all this: income inequality.

Lukas Neville, a doctoral student at Queen’s University in Ontario, reports in the latest issue of Psychological Science that there’s more evidence of academic dishonesty in U.S. states with bigger gaps between the rich and the poor. Those gaps, he speculates, erode trust among people—something that’s been found by other researchers—and less trust means more cheating.

The evidence in the paper has limits. For starters, it’s circumstantial, based on the frequency of Google searches for things that seem linked to cheating on papers. Neville looked at Google searches for phrases like “free term paper” and the names of Web sites like Essaytown that offer paper-writing services or pre-written papers. Google breaks statistics on these searches out by state, which is a big help. It means that Neville was able to compare the number of searches in each state to measures of income inequality from the U.S. Census Bureau. (He did balance things out, statistically, to account for different numbers of college students in each state, how large the colleges are, and other factors that could affect the frequency of searches.)

But circumstantial or not, the association was clear: Google searches for free term papers and other cheating hallmarks occurred most often where the rich were richer and the poor were poorer. Surveys by social scientists have also found those places to be the states where people were least likely to say they trusted other people. If students don’t trust one another, Neville suggests, they might be more likely to think their classmates are cheating—and thus more likely themselves to cheat to keep up.

That may be speculative, but the income gap-distrust connection is fairly well-grounded. Richard Wilkinson, professor emeritus of social epidemiology at the University of Nottingham, has found a similar link through his research, which he described last summer in a TED talk. How much people trust other people—as measured by social surveys—depends more strongly on income disparities than on other variables. He went through all 50 U.S. states and found that trust levels were highest—between 50 and 60 percent—in states like Iowa, New Hampshire, Utah, and Wisconsin where the gap between the top and bottom income levels was the lowest. In states where income inequality was highest, like Alabama, Mississippi, and West Virginia, trust levels were lowest, below 30 percent.

“The differences between us and where we are in relation to each other now matter very much,” he said. He found a similar pattern internationally. People in countries with high income inequality (Australia, Portugal, the United States) trusted others much less than did people from countries with less inequality, like the social democracies of Sweden, Norway, and Denmark.

Neville does not suggest moving all colleges to Denmark. But he does think that honor codes, which have been shown to promote academic integrity, could be a more practical solution because they enhance trust. The codes, and their penalties, reassure students that the people next to them are not cheating their way through school.