Less intelligent people are more likely to hold discriminatory attitudes towards same-sex couples, according to new research from Australia.

The finding, which appear in the journal Intelligence, adds to a growing body of literature that indicates less intelligent people tend to express more prejudicial attitudes.

“Despite the significance and contemporaneity of the subject matter, few studies have specifically addressed the links between cognitive ability and attitudes towards LGBT issues,” said study author Francisco Perales of The University of Queensland.

The study analyzed data from 11,654 individuals who participated in the Household, Income and Labour Dynamics in Australia Survey.

Cognitive ability was assessed using three tests: the National Adult Reading Test, the Symbol Digits Modalities Test and the Backwards Digit Span test.

Perales found that those who scored lower on the tests were more likely to disagree with the statement “Homosexual couples should have the same rights as heterosexual couples do.” The link was strongest for verbal ability.

This association held even after controlling for a number of socio-demographic and economic variables — including education.

“Altogether, the findings provide clear evidence that cognitive ability is an important precursor of prejudice against same-sex couples,” Perales wrote in his study.

“The findings in this report suggest that strategies aimed at increasing participation in (higher) education and improving levels of cognitive ability within the population could act as important levers in counteracting prejudice towards same-sex couples and LGBT people.”

But the findings don’t mean that everyone who opposes rights for same-sex couples is unintelligent.

In addition, a 2016 study on racism in the United States found evidence that smart people could be just as prejudicial as their less intelligent peers — they were just better at concealing it.

The study was titled: “The cognitive roots of prejudice towards same-sex couples: An analysis of an Australian national sample“.