Recent research published in scientific report provide evidence that combining multiple small psychological differences can accurately predict a person’s gender in 80% of cases. The findings suggest that a combination of these differences in cognition, personality, and interests may also help explain why certain occupations tend to be dominated by men or women. This study provides new insights into how subtle psychological changes shape real-world career trajectories.
In psychological research, the differences between men and women generally tend to be small. When looking at individual characteristics, the range of scores for men and women overlaps widely. For example, women may have slightly higher average scores on tests of verbal memory, but many men still outperform many women on these particular tasks. This overlap has led some scholars to propose that psychological gender differences have minimal impact on people’s lives and society as a whole.
At the same time, there are significant disparities between men and women in certain real-world areas. One notable example is career choice, where certain fields remain highly segregated by gender. The authors wanted to understand how small individual differences accumulate to create these larger social patterns.
“We have been conducting research on sex differences in cognition for many years, with the aim not only to identify where such differences exist, but also to understand why they occur,” said Agnetha Herlitz, professor of psychology at the Department of Clinical Neurosciences at Karolinska Institutet. “Our findings generally show that there are small sex differences in most cognitive abilities, so small that some argue there is no effect.”
“This observation led us to consider a broader question: If we examine many small sex differences collectively, could their combined effects be more substantial and meaningful?” Herlitz explained. “Research therefore asks the question: Can we predict an individual’s gender and occupational sex ratio based on cognition, personality, and interests?”
To investigate this, scientists selected psychological measures that consistently showed minor gender differences across different cultures and age groups. These include cognitive skills such as episodic memory, which is the ability to remember specific past events, and spatial awareness, which involves visualizing and manipulating objects in your mind. They also tested verbal fluency, the ability to quickly generate words, and emotional recognition.
These also included five major dimensions of personality. These consist of extraversion, which measures sociability. Collaborativeness that reflects warmth and cooperation. Demonstrates integrity, organization and discipline. Captures neuroticism, a tendency towards negative emotions. An openness to experience that reflects curiosity and creativity.
Finally, we measured whether participants generally had a strong interest in interacting with people or handling physical objects. These basic variables were chosen because they represent well-studied psychological phenomena that are not trivially linked to biological sex. The researchers suspected that assessing these traits together might reveal a much wider range of psychological differences than examining a single trait alone.
Researchers recruited 2,767 participants from Sweden, including 1,465 women and 1,302 men. Participants were between 35 and 45 years of age, a narrow age range chosen to focus on individuals with established careers while reducing age-related variation in cognitive ability. People completed a comprehensive online assessment using their own computers in a quiet environment.
During the evaluation, participants completed 13 specific tasks and questionnaires. To measure verbal episodic memory, subjects were asked to memorize and later recall a list of words. Another memory task tested people’s ability to recognize pictures of faces they had seen previously. For spatial ability, participants matched the angles of different lines, rotated three-dimensional objects in their heads, and found matching shapes.
Language productivity was assessed by having participants write down as many words starting with a specific letter as possible within a limited amount of time. The scientists also tested emotion recognition by asking participants to identify people’s emotions based solely on pictures of their eyes. To assess personality, participants rated themselves on a standard 60-item questionnaire.
Regarding interests, participants indicated how much they enjoyed certain everyday situations. These include person-centered activities, such as listening to a conversation in a crowd, and object-centered activities, such as fixing a toaster. Finally, participants reported their current or recent occupation.
The researchers then matched these reported occupations with Swedish national register data. This allowed us to determine the general proportion of men and women working in each specific role. For example, kindergarten teachers are given a score that reflects the high representation of women in the profession nationally.
The authors found expected differences between men and women across individual tasks. Women performed better on average in verbal fluency, verbal episodic memory, facial recognition, and emotion recognition. They also scored high on all five personality dimensions and showed a strong interest in people.
Men tended to perform better on two spatial tasks: determining the angle of a line and rotating an object in your head. Additionally, men showed a much stronger interest in interacting with physical objects. Most of these individual differences were relatively small when viewed individually.
But when the researchers combined scores from all 13 tasks and surveys into a single predictive model, a clear pattern emerged. The model accurately predicted whether participants were male or female in 80% of cases by assessing the individual’s overall psychological profile. The model was unbiased and predicted male and female identities with similar accuracy.
“While we expected the pattern, we were somewhat surprised by how accurate it was,” Herlitz told SciPost. “However, we could have further improved the prediction accuracy by including predictors that are strongly and directly linked to sex, such as sexual attractiveness or body shape, or by incorporating many other psychological variables with small gender differences. Alternatively, we could have further improved the prediction accuracy by using more fine-grained predictors, such as individual test items rather than composite domain-level data.”
The most accurate predictors of a person’s gender were performance on a mental rotation task, verbal episodic memory, level of neuroticism, performance on a line angle task, and interest in things. For example, we found that the higher the score on the Interest Questionnaire, the much less likely the participant was to be female. Even when scientists removed the three strongest predictors from the statistical model, they were still able to accurately predict participants’ gender with 70% accuracy.
Complex psychological differences also provided evidence for real-world career choices. Researchers found that a person’s cognitive, personality, and interest profile accounted for about 22 percent of the gender differences in occupations. For example, people with a strong interest in physical objects were strongly predicted to work in male-dominated fields, regardless of their actual gender.
To understand this effect, the authors examined the psychological profiles of hypothetical typical men and women. They calculated that a man with a typical female psychological profile would work in a workplace with about 10 percent more women than a man with a typical masculine profile. This suggests that a combination of psychological differences plays a notable role in guiding people into specific types of work.
“I think the most important thing is that we will be able to better understand why women and men appear to be more different in everyday life than the usually fairly small sex differences in basic psychological attributes would suggest,” Herlitz said. “The link between sex differences in cognition, personality, and interests and sex ratio in career choice is one way to anchor abstract questions about predicting gender into something more important and make it more than just a statistical exercise.”
Although this study provides robust data, the authors noted some limitations to their approach. A cross-sectional design means that the study examines only a single time point. Therefore, it cannot be proven that these psychological characteristics are the direct cause of people choosing particular jobs.
“It’s good to keep in mind that this is an observational study, so we can’t claim that sex differences in psychological attributes drive men’s and women’s career choices into male-dominated or female-dominated occupations,” Herlitz explained. This highlights a common limitation of survey-based psychological research.
Although it is unlikely that a job completely changes a person’s basic cognitive abilities or personality, the relationship between interests and career paths is likely complex and interactive. Another limitation involves the online testing environment. Because participants took the test at home, researchers could not control for distractions or changes in effort level.
However, this lack of control affects both male and female participants equally. Therefore, it is likely that the overall pattern of findings did not change. The authors also emphasized that their study was based on a binary view of gender, matching legal sex at birth to current legal gender.
They excluded a small number of participants who had transitioned or reported a different gender identity. This decision was made primarily because hormonal treatment can independently influence cognitive and behavioral outcomes. Future studies with larger samples could include non-binary individuals and people with different gender identities to provide a more comprehensive view of human psychology.
These findings are also easily misinterpreted as evidence of strictly male or female brains. Researchers explicitly caution against this view. Individual characteristics still show significant overlap between genders, so no single characteristic can definitively classify a person as male or female.
Rather, this study suggests that human behavior is shaped by a complex interplay of many small characteristics. By looking at these traits in combination, we can better understand how their nuanced differences influence our life choices. This finding provides a framework for exploring how fundamental psychological fluctuations contribute to larger social patterns.
In the future, scientists plan to build on these findings to better understand workplace disparities. Professor Herlitz said: “As well as continuing to investigate explanations for psychological sex differences, we will also address in more detail the question of why men and women tend to work in different occupations.”
The study, “The Power of Many Small Sex Differences in Cognition, Personality, and Interests,” was authored by Agnetha Herlitz, Joachim KE Frostegård, Martin Asperholm, Richard Brännström, Elisabeth Guest, Joachim Martinsen, Hedda Sonnegaard, Kimmo Sorjonen, Lisa B. Soler, and Björn N. Persson.
