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A massive new study suggests that growing up in a society marked by corruption, inequality, poverty, and violence may influence how willing people are to behave selfishly—even if it comes at a cost to others. The findings, published in the Proceedings of the National Academy of Sciences, provide evidence that aversive societal conditions are linked to the development of personality traits associated with callousness, exploitation, and moral disregard.
In an analysis of more than 1.7 million individuals across 183 countries and over 140,000 people from all 50 U.S. states, researchers found a consistent, though modest, association between adverse societal conditions and higher levels of what psychologists refer to as the “Dark Factor of Personality.” This general factor reflects a tendency to prioritize one’s own interests while disregarding—or even causing—harm to others, often accompanied by beliefs that justify such behavior.
Dark personality traits refer to enduring patterns of thoughts, feelings, and behaviors that are socially and ethically aversive. These include traits like narcissism, psychopathy, Machiavellianism, sadism, and spitefulness. Although each trait emphasizes different features—such as callousness in psychopathy or manipulativeness in Machiavellianism—research over the past decade suggests they share a common core.
This shared disposition, termed the Dark Factor of Personality (or simply “D”), is thought to reflect a general tendency to pursue personal gain at the expense of others, underpinned by beliefs that such behavior is justifiable. For example, someone high in D might believe that “everyone looks out for themselves” or that “most people deserve what they get.”
Just as intelligence researchers have identified a “g” factor that underlies cognitive ability, personality researchers argue that D underlies all dark traits. People high in D are more likely to behave dishonestly, seek revenge, exploit others, and rationalize unethical behavior. But what shapes the development of this psychological tendency?
The authors of the new study hypothesized that certain adverse social environments might foster the development of darker personality profiles. They refer to these as “aversive societal conditions” (ASC), measured by four factors: corruption, economic inequality, poverty, and violence.
The idea is that in settings where exploitation, injustice, and insecurity are common, self-interested behavior might be perceived not only as acceptable but as necessary for survival. In such societies, people may learn that others cannot be trusted, that cheating pays off, or that harming others is a legitimate way to get ahead. Over time, such beliefs may become internalized and crystallize into stable personality traits.
The study was motivated by “an intertwining between theoretical and pragmatic reasons,” according to lead author Ingo Zettler of the University of Copenhagen. “Theoretically, there have always been ideas that societal conditions contribute to the proliferation of certain personality traits in a society, but research has not looked too much into very aversive (or antisocial) personality characteristics so far. Pragmatically, we were able to collect survey responses from close to two million people from more than 180 countries, which, we believe, is a good data set to explore whether aversive societal conditions also relate to the proliferation of aversive personality characteristics across societies.”
The researchers created an index of aversive societal conditions across countries and U.S. states using publicly available data. Importantly, they focused on how these conditions looked about 20 years before personality data were collected, to examine whether long-term exposure during formative years predicted later personality tendencies.
The researchers drew on a massive dataset of individuals who voluntarily completed the Dark Factor of Personality questionnaire through an online platform, which offers feedback on personality. (You can take the test here.) After applying various quality control checks and matching participants’ self-reported country with geolocated IP data, the final sample included 1,791,542 people from 183 countries, and a separate sample of 144,576 individuals across 50 U.S. states.
Each person completed a validated short version of the D questionnaire. Items included statements such as “My own pleasure is all that matters” and “People who mess with me always regret it.” Participants rated how much they agreed or disagreed with each item.
For each country and state, the researchers calculated an ASC index based on corruption, income inequality, poverty rates, and homicide rates from 2000–2004. These measures were combined using principal component analysis to create a single score reflecting how aversive the local societal conditions were at that time.
Multilevel regression analyses revealed that individuals living in countries or states with higher ASC scores tended to have higher D scores. While the effect sizes were small, the findings were statistically significant and consistent across both the international sample and the 50 U.S. states.
The researchers found that average levels of dark personality traits varied systematically across U.S. states, with certain regions consistently scoring higher on the Dark Factor of Personality than others. States such as Nevada, New York, Texas, Louisiana, California, Mississippi, Alabama, Georgia, North Carolina, and Tennessee were among those with the highest average D scores. These states also tended to have higher levels of aversive societal conditions.
In contrast, states such as Vermont, Utah, New Hampshire, Oregon, Maine, Alaska, Minnesota, Idaho, Montana, and Colorado had the lowest average D scores in the sample. These states generally exhibited more favorable socioecological conditions during the early 2000s, with lower levels of violence, corruption, and poverty.
“We did expect to find a link between aversive societal conditions and the proliferation of aversive personality characteristics, but it was nice to see this replicating within the same country,” Zettler told PsyPost.
These findings suggest that people’s personality traits—specifically those related to selfishness, moral disengagement, and interpersonal harm—are not only shaped by individual or genetic factors but also by the broader social environment. This supports the view that personality development is sensitive to socioecological conditions, particularly during adolescence and early adulthood.
In societies marked by widespread corruption and violence, people may learn that exploiting others is normal or even necessary. Over time, repeated exposure to such environments may promote beliefs and behaviors that align with the Dark Factor of Personality.
Interestingly, the researchers found that this association was stronger among younger individuals and in societies that emphasize individualism. These patterns suggest that cultural values and developmental timing may moderate the influence of aversive societal conditions.
The results also held up when using alternative measures of societal aversiveness, such as an index of rule violations (including tax evasion and fraudulent politics), providing further support for the link between harsh environments and the proliferation of dark traits.
“I would say there are two main take-aways,” Zettler said. “First, the average levels of aversive personality characteristics differ across societies. While there are also many differences between people within the same society, there are also differences between societies. Second, reducing aversive conditions in one’s society does not only facilitate the life for several people in the society, but might also reduce the likelihood of very aversive (or selfish) individuals in this society in the future.”
While the study’s scale is impressive, there are still some caveats to consider. First, the researchers used online convenience samples, meaning the participants were not randomly selected and may not fully represent the general population. Second, although the analysis accounts for time lags to reduce the risk of reverse causality, the data are still correlational. This means the findings point to an association—not a definitive causal link—between adverse environments and dark personality traits.
Another consideration is the potential variability in the quality of the societal data used to build the ASC index. For example, some countries may underreport corruption or violence, which could influence the accuracy of the index. The researchers also acknowledge that they do not know how long participants had lived in their stated country or state, making it difficult to determine the duration of exposure to aversive conditions.
The study opens the door to further research on how environments interact with personality development. “We are continuing in trying to better understand the development of the D factor, as well as how it expresses in certain behavior in certain situations (e.g., based on different situational affordances),” Zettler said.
The study, “Aversive societal conditions explain differences in ‘dark’ personality across countries and US states,” was authored by Ingo Zettler, Lau Lilleholt, Martina Bader, Benjamin E. Hilbig, and Morten Moshagen.
