Republican presidential frontrunner Donald Trump is renowned for making no apologies for his many provocative statements and new research may show that he is right to never say “sorry.”

Writing in The Washington Post Wednesday, Richard Hanania, a political science and statistics graduate student the at University of California – Los Angeles, shared his findings on what effects a public figure’s apology has for making up for remarks some find offensive.

Hanania surveyed over 500 people to get their response to two statements made by Rand Paul and former Harvard University President Larry Summers. Respondents were shown Rand Paul’s skepticism of parts of the Civil Rights Act and half of them read a statement where Paul didn’t back down and the other group read a statement that made it appear that the senator apologized. (In real life, he never apologized.)

Hanania found that the apology had virtually no effect on whether a respondent would vote for Paul.

However, an apology made a notable difference in the case of Larry Summers. In 2005, the then-Harvard president got in hot water for saying genetics play a role in why there’s so few female scientists. Half the respondents read a statement where Summers appeared to double-down on the remarks and the other half read his apology for the comments. Sixty-four percent of those surveyed said Summers should be punished after reading the apology, while only 56 percent of those who read the non-apology said he should be punished.

In other words, the apology seemed to have a negative effect for the Harvard official.

“Given these results, why would politicians apologize at all?” Hanania wrote. “To be sure, my experiments certainly don’t suggest that it is always inadvisable to apologize. Nor can my findings speak directly to Trump. Nevertheless, my findings offer a cautionary tale to anyone who assumes that the best remedy for controversial statements is ‘I’m sorry.'”

While the UCLA researcher does say his particular research can’t be directly tied to the Trump phenomenon, he does mention two other scientifically-proven theories that may explain why the billionaire mogul’s no-apology bravado is proving so popular among GOP voters.

Hanania points to research that shows that participants who back down in disputes usually lose support among observers, who then become more likely to demand punishment. He also brings up studies that show people favorably view overconfidence that’s willing to go to the point of breaking rules.

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