Middle-school students were 18 percent more likely to report being bullied in if they lived in areas where voters supported Trump over Hillary Clinton. (Photo: Mandel Ngan/AFP/Getty Images)

During and immediately after the 2016 presidential campaign, numerous reports emerged of an uptick in bullying behavior. As the mother of a bullied elementary school student told CBS News just after the vote: "The man that won the election has been modeling that it's OK to bully people ... and now children think it's OK to be mean too."

Definitively proving such a dynamic is difficult, but a new study of Virginia schools provides the most compelling evidence yet that the 2016 campaign has coarsened kids' behavior. It reports that, in the spring of 2017, middle school students were 18 percent more likely to report being bullied if they lived in areas where voters supported Donald Trump over Hillary Clinton.

In previous surveys, there were no significant differences in bullying rates between Democratic- and Republican-leaning communities.

While the findings cannot prove cause and effect, "they do provide some credence to the widespread perception that some types of teasing and bullying have increased, at least in some localities," lead author Francis Huang of the University of Missouri said in announcing the results.

He finds the results troubling, given the "abundant evidence that peer victimization, especially bullying, is associated with a decline in student engagement and academic achievement," along with increased risk of mental-health problems such as depression.

The study used data from a statewide "school climate survey" taken by seventh- and eighth-graders throughout Virginia in the spring of 2013, 2015, and 2017. The kids—more than 60,000 in both 2015 and 2017—responded to about 100 questions regarding their experiences in school.

The researchers noted their responses to a series of statements, including "Bullying is a problem at this school" and "Students in this school are teased or put down about their sexual orientation." The students responded to each on a four-point scale, from "strongly disagree" to "strongly agree."

They were also asked whether they had been verbally, socially, or cyber-bullied in the past year—and if so, how often. Bullying was defined for them as "the repeated use of one's strength or popularity to injure, threaten, or embarrass another person on purpose."

The researchers noted the percentage of voters who supported Trump in the 2016 election in the city or county where each school resides. They then adjusted the numbers for other factors that could influence bullying, including neighborhood socioeconomic status and parents' educational level.

They found the rate of students who reported they had experienced bullying in some form was 18 percent higher in localities that voted for Trump compared with those that supported Clinton. Students in Trump territory were also 9 percent more likely to report having observed peers being teased or put down because of their race or ethnicity.

"It does not seem plausible that large numbers of school-age youth were closely following the president's statements," write Huang and co-author Dewey Cornell. "It seems more likely that there are multiple indirect effects and intermediate steps" between thuggish campaign rhetoric and actual bad behavior on the part of adolescents.

The results suggest that, while middle school students may not be watching Oval Office addresses, their young minds are nevertheless absorbing the message that bullying is acceptable behavior. And apparently, when the social environment allows it, at least some of them act accordingly.