A new study from Australia has found that less intelligent people are more likely to express discriminatory views toward same‐sex couples. The research, published in the journal Intelligence, examined data from over 11,500 Australians and adds to a growing body of evidence suggesting that cognitive ability plays a role in shaping our social attitudes. In particular, the study found that individuals who scored lower on tests of mental ability were less likely to support equal rights for same‐sex couples, with the strongest connection appearing in tests of verbal ability.
Researchers undertook the study to better understand the factors that contribute to negative attitudes toward same‐sex couples. While previous work in countries like the United States, Canada, and parts of Western Europe has linked lower cognitive performance to more prejudicial views against various groups—including ethnic minorities, migrants, and women—only a few studies had examined these associations in relation to lesbian, gay, bisexual, and transgender issues.
Given that many non-heterosexual individuals continue to experience discrimination in areas such as income, health, and social inclusion, the study sought to identify whether differences in cognitive ability could help explain why some people oppose equal rights for same‐sex couples.
“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.
To explore this connection, Perales used information from the Household, Income and Labour Dynamics in Australia Survey, one of the world’s largest panel studies. This survey has been collecting detailed data every year since 2001 from Australians aged 15 and older, using a careful and representative sampling method to ensure that the findings accurately reflect the broader population. For this study, the researchers focused on responses from 11,654 individuals.
Data on cognitive ability were gathered in 2012, and three different tests were used to capture a range of mental skills. Later, in 2015, the survey asked participants about their views on whether same‐sex couples should have the same rights as heterosexual couples.
The study measured cognitive ability using three distinct tests, each designed to assess a different facet of mental performance. The first test was a shortened version of the National Adult Reading Test, in which respondents were asked to correctly pronounce 25 irregularly spelled words. This test is widely used as an estimate of verbal ability because it reflects the skills and knowledge accumulated over a person’s lifetime.
The second measure was the Symbol Digits Modalities Test, which required participants to quickly match symbols to numbers based on a printed key within a 90-second period. This test focuses on a person’s speed of visual processing and their ability to manage multiple pieces of information at once. The third test was the Backwards Digit Span test, a measure of working memory that involves listening to a sequence of numbers and then repeating them in reverse order.
Attitudes toward same‐sex couples were gauged using a single, straightforward question: respondents were asked to rate how much they agreed or disagreed with the statement “Homosexual couples should have the same rights as heterosexual couples do.” Answers were given on a seven‐point scale, where higher scores reflected stronger support for equal rights.
On average, responses indicated a generally favorable view toward same‐sex couples; however, when the researchers compared these responses to the cognitive test scores, a clear pattern emerged. Individuals who scored lower on the cognitive tests were more likely to disagree with equal rights for same‐sex couples, even when other factors such as age, gender, and education were taken into account.
To isolate the effect of cognitive ability on social attitudes, Perales controlled for factors such as gender, age, sexual identity, religiosity, parental education, and even the remoteness of the area where respondents lived. But the link between cognitive ability and attitudes held strong even after adjusting for these socio-demographic and economic variables.
Even when educational attainment was included in the analysis—a factor that itself is known to be linked with more liberal or inclusive views—the connection between lower cognitive ability and less supportive attitudes toward same‐sex couples remained significant. This suggests that while higher education is associated with more tolerant views, the impact of cognitive ability runs independently of education.
One interesting aspect of the study was the finding that the relationship between cognitive ability and support for same‐sex couple rights was strongest when measured by the verbal ability test—the National Adult Reading Test. This indicates that the ability to understand and use language, and the knowledge accumulated over one’s lifetime, may be particularly important in shaping one’s social attitudes.
People who excel in language-related skills might be better equipped to process complex ideas and may be more open to alternative viewpoints. In contrast, tests that measure other aspects of cognitive function, such as visual processing speed or working memory, showed weaker associations with attitudes toward same‐sex couples. This finding aligns with previous research suggesting that verbal skills share a substantial amount of overlap with general intelligence, and that these skills can be a powerful indicator of how people approach and interpret social issues.
“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.”
It is also important to emphasize that the study does not suggest that every person who opposes equal rights for same‐sex couples lacks intelligence. Prejudice is a multifaceted issue influenced by a wide range of factors, including cultural background, personal experiences, and political ideology.
Other research, such as a 2016 study on racism in the United States, has found that individuals with higher intelligence can also harbor prejudicial views—they may simply be more adept at concealing them in social settings. These findings highlight that while there is a statistical relationship between cognitive ability and discriminatory attitudes, intelligence is only one of many factors that contribute to how people form their opinions.
The study was titled: “The cognitive roots of prejudice towards same-sex couples: An analysis of an Australian national sample“.
