Is Morality Genetic?

Where do your moral values come from? The intuitive answer—and a popular assumption both at large and within the field of psychology—is that you learn morality from your culture, usually by way of parental, peer, and institutional influences. Psychological theorists from Freud on have endorsed this idea. We therefore routinely assume that differences in moral positions between people are the result of their different upbringing, social circumstances, and experiences.

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Now clearly, differences in parental behavior and environmental conditions do exist, and both may impact one’s behavior across multiple domains. Yet along with reflecting our lived experience, our behavior always carries the imprint of our genetic inheritance.

Developmental research over the last 50 years has shown that many outcomes once attributed to the parenting or social environment are in fact strongly genetic. Some of these findings have enjoyed a positive reception. For example, the findings that autism, schizophrenia, and sexual orientation are coded in biology rather than the results of deficient parenting have helped to correct grave historical injustices.

Other such findings have been more difficult for the cultural intuition, and discourse, to absorb. For example, many people are surprised to hear that children of divorce are more likely to divorce themselves not because of their early experiences with divorced parents but rather due to inheriting from their parents those genes that make marital instability more likely. Likewise, many are surprised to hear that parental behavior—the way parents parent—generally has little to no effect on children’s personalities.

Either way, the fact remains that many things we used to believe are the product of upbringing and social environment are in fact under the strong control of our genetic inheritance.

One intriguing issue where old notions appear due for a revision is morality. For years, researchers and laypeople alike assumed that various moral sentiments are transmitted across generations socially—by environments' messaging, through rules that parents establish for their kids, through socialization agents such as teachers and the media, and through children’s modeling of the above.

Strategic interest hypothesis

Contemporary research is challenging this view. Evolutionary psychologists have proposed the so-called "strategic interest hypothesis" which argues that people’s emotional responses and behavioral choices are calibrated by evolution to serve our strategic interests, that is our survival and reproduction goals. Thus, we favor social behaviors that support our mating strategy, which is largely heritable. This logic applies to our moral positions as well, which are self-serving and work to maintain our fitness advantages.

In this view, then, sexual strategy dictates moral preference. Those who are invested in a mating strategy of long-term commitment (“dads” in evolutionary psychology lingo) will deem immoral those behaviors that undercut their position. Those who stand to benefit from a short-term, noncommittal mating strategy (“cads”) will tend to approve of behaviors that promote their position.

Reactive heritability

In looking to explain how genes play into our behavioral strategies, Stanford psychologists John Tooby and Leda Cosmides have advanced the idea of “reactive heritability,” arguing that certain behavioral traits emerge out of heritable aspects of an individual’s genetic makeup. For example, physically stronger individuals are more likely to benefit (in terms of survival and reproduction) from aggression than smaller ones, which means that size, a heritable physical feature, would predict aggressiveness—a behavioral trait—making it in effect heritable even if no specific genes directly encode for it.

The same mechanism may account for the development of moral positions, as the physically stronger person may opt to approve of the morality of economic inequality and aggressive military action. Research in support of this view has shown that sexual strategy predicts people’s moral views in the realm of sexual behavior, such as toward contraception, abortion, pornography, and same-sex marriage.

Yet the effects of sexual strategy on moral values may extend beyond sexual topics. For example, a new (2021) study by European researcher Annika Karinen and colleagues sought to apply this new perspective to attitudes about drug use. The authors correlated measures of drug condemnation and sexual strategy in a sample of over 8000 Finnish twins and siblings. (In studies like these, finding that correlations are stronger between twins than between siblings serves as evidence for genetic influence, since twins share all their genes and siblings only 50%).

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Indeed, the authors found that “approximately 75% of the phenotypic covariance between drug condemnation and sexual strategy was accounted for by genes.” Moreover, they found that, as predicted by the sexual strategy hypothesis, high-commitment-oriented individuals were more likely to condemn recreational drug use (in part, they suggest, since drug use is associated with casual, noncommittal sex). These effects remained even after controlling for personality, religiosity, and political ideology.

Finally, they detected “no influence of shared environmental effects—which presumably would include parental rearing, the influence of siblings, socioeconomic status, or childhood neighborhood—on either condemnation of recreational drugs or sexual strategy.” The authors conclude that “results are consistent with the proposal that some moral sentiments are calibrated to promote strategic sexual interests, which arise partially via genetic factors.”

These types of findings, providing support for the reactive heritability view, may have social implications beyond the lab. For one, they further undermine the popular notion that within-family similarities across a host of behavioral outcomes (such as aggressiveness) and moral sentiments (such as views toward drugs and sex) reflect chiefly a process of social transmission from parents to offspring. Rather, these findings suggest that much of what we intuit to be parenting or social effects can in fact be attributed more accurately to the powerful whisperings of our genetic heritage.

The notion that high-end human attributes such as moral values are under strong genetic control may unnerve some people. Yet, just as listening and understanding someone’s point of view does not imply agreeing with them, so does recognizing the predictive power of genes not imply surrendering to that power.

Moreover, contrary to popular belief, genetic effects are not impervious to environmental intervention. Your vision and eye color are under strong genetic control, yet environmental intervention (contact lenses) can change both. PKU is a rare inherited disorder that can lead to serious health problems. Yet it is treated effectively with a proper diet, an environmental intervention. Thus, recognizing properly the actual forces that shape our moral values may inform our self-understanding, as well as the societal conversation about morality. Such recognition may also help us avoid misplacing blame, and facilitate more effective persuasion and intervention efforts.