Simply telling people that their opinions are based on morality will make them stronger and more resistant to counterarguments, a new study suggests.

Researchers found that people were more likely to act on an opinion – what psychologists call an attitude – if it was labeled as moral and were more resistant to attempts to change their mind on that subject.

The results show why appeals to morality by politicians and advocacy groups can be so effective, said Andrew Luttrell, lead author of the study and a doctoral student in psychology at The Ohio State University.

“The perception that an attitude we hold is based on morality is enough to strengthen it,” Luttrell said.

“For many people, morality implies a universality, an ultimate truth. It is a conviction that is not easily changed.”

The key finding was how easy it was to strengthen people’s beliefs by using the ‘moral’ label, said Richard Petty, co-author of the study and professor of psychology at Ohio State.

“Morality can act as a trigger – you can attach the label to nearly any belief and instantly make that belief stronger,” Petty said.

Other co-authors of the study were Pablo Briñol of the Universidad Autónoma de Madrid in Spain and Benjamin Wagner of St. Thomas Aquinas College. The results are published in the July 2016 issue of the Journal of Experimental Social Psychology.

In one experiment, 183 college students read an essay favoring the adoption of a senior comprehensive exam policy at their university. They were asked to provide their thoughts in response to the essay.

The students were then told by the researchers that the views they expressed seemed to be based on morality, tradition or equality.

Participants were then asked to rate how willing they would be to sign a petition in favor of the exam policy and to put their names on a list of students who favor the exam policy, and which way they would vote on the issue.

The results showed that the attitudes of students who were told that their views on the exam policy were based on morality were more likely to predict their behavior than the attitudes of students who were told their views were based on equality or tradition.

“Morality had a lot more impact than the values of tradition and equality,” Luttrell said.

“Students were more likely to act on their opinion of the student exam policy if they thought it had to do with morality.”

Two other experiments involved a more universal issue – recycling. One of these studies involved college students and the other involved older adults who were not in school.

In these experiments, participants read a brief introduction to the topic of recycling and then were asked to list the thoughts they had about the issue.

In this case, the researchers told the participants that their thoughts related to either morality or to the practicality of recycling. Participants then reported their attitudes toward recycling.

Nearly all of the participants had positive views on recycling. So the researchers then asked them to read a short persuasive essay with arguments against the benefits of recycling.

Then, the researchers again measured the participants’ views on recycling.

Results showed that participants who were told their views on recycling were based on morality were less likely to change their minds than those who were told their views were based on practical concerns.

“People held on to their moral beliefs in a way they didn’t for other values we studied, like tradition, equality and practicality,” Luttrell said.

“But what was remarkable was how easy it was to lead people into thinking their views were based on moral principles.”

The results suggest that appeals to morality can be very effective to groups and political candidates trying to appeal to their supporters.

“People may be more willing to vote for a candidate or give money to an advocacy group if they believe it is a matter of morality,” Luttrell said. “They’re also less likely to be swayed by the opposition.”