Research published in evolutionary psychology found that people who espoused more conservative social attitudes tended to report having more children across a large international sample, suggesting that these attitudes may be related to modern reproductive patterns.
Social attitudes are broad orientations toward social life, including views about religion, politics, class, gender roles, sexuality, and authority. In this article, “conservatism” is used in a broad sense to refer to tendencies common to a variety of attitudes, including right-wing ideology, religiosity, low support for gender equality, and preference for the religiosity of one’s romantic partner.
This study builds on previous research showing that these attitudes are often correlated and that many social attitudes exhibit some degree of heritability. That heritability is part of what makes it interesting from an evolutionary perspective, especially when it also relates to the number of children humans have.
Janko Medjedovic set out to find out just that. His motivation came from a gap in evolutionary behavioral ecology. Although researchers have extensively studied how personality, cognition, and religiosity relate to fertility, broader social attitudes have been largely ignored from the discussion. Given that conservative worldviews tend to emphasize family formation, traditional gender roles, religious commitment, and pronatalist values, Medjedovic wanted to test whether people with these attitudes actually reported having more biological children.
This study used a publicly available dataset originally collected for research on love and mate preferences. The full dataset includes 117,293 participants from 175 countries, and data was collected primarily online in 2021 (Algeria and Morocco used paper-and-pencil surveys, Russia used Toloka, and Iran used Google Forms). After removing participants with missing data on key variables and excluding countries with fewer than 100 respondents, the final analytic sample included 78,754 participants from 72 countries. Approximately two-thirds of the sample were women.
Participants answered questions about political ideology (single item ranging from far left to far right), support for gender equality (3-item scale with higher scores meaning stronger support), religiosity (11 self-reported items), religious preference for ideal romantic partner (11 parallel items), and number of biological children. They also reported their gender, age, education level, and social class. These variables can shape both attitudes and family formation in important ways.
Medjedovic found that conservative social attitudes were consistently associated with higher birth rates. Participants who reported stronger right-wing ideology, stronger religiosity, stronger preferences for religiosity in romantic partners, and lower support for gender equality were more likely to report having more children. This association was generally small, with age being the strongest predictor of how many children someone would have. But the association was consistent enough to show up reliably in a sample of nearly 80,000 people across 72 countries.
The magnitude of the relationship between conservative attitudes and fertility also varied considerably across countries, even reversing its direction in a few cases. This suggests that the relationship between attitudes and fertility is not a fixed and universal mechanism, but that national and cultural contexts shape it in meaningful ways.
Some more specific patterns also emerged. Right-wing ideology and low support for gender equality were more strongly associated with fertility for women than for men, suggesting that conservative attitudes may be particularly linked to reproductive outcomes for women in this dataset. Self-reported religiosity was strongly associated with preference for religious romantic partners, and interactions between these variables showed that people who were less religious and preferred nonreligious partners had particularly low fertility. Education further evaluated the findings. Right-wing ideology predicted higher fertility among less educated participants, but not among more educated participants.
The authors also found small quadratic effects, but explained these as small deviations from a linear association rather than strong evidence of an apparently nonlinear pattern.
Medjedovic points out that there are some important limitations. Female and highly educated participants were likely to be the majority, and many of the participants were young enough that they may not have yet completed their reproductive years (mean age for men = 31.5 years, women = 29.5 years). The cross-sectional design also means that this study cannot establish that conservative attitude cause They say they have a high reproductive capacity, or that they have definitely evolved through selection. Similarly, the reliability of the measurements is also limited because multiple attitudes were measured with only one item.
Still, the findings make a reasonable case for social attitudes to receive more attention in research on fertility differences, while also raising the possibility that attitudes are relevant to the evolution of modern human behavior.
The study “Conservative social attitudes are associated with fertility: the possibility of positive directional selection” was authored by Janko Medjedovic.
