In dystopian worlds like the one portrayed in the TV show Squid Game, people are pushed to do unconscionable things by extremities of inequality, greed, corruption, and violence.
While it’s tempting to say these stories are just fiction, a recent global study says there’s a kernel of truth to them.
The study says that dark personality traits, defined as those focused on maximising personal gain with little regard for others’ wellbeing, are linked to levels of societal conditions such as inequality, corruption and violence.
The results suggest that personality traits like narcissism or psychopathy might be viewed, at least partially, as the outcome of a person’s environment – making them, in other words, a kind of learned behaviour.
People with high levels of psychopathy, narcissism and Machiavellianism, the so-called ‘Dark Triad’ of personality traits, are often viewed as a product of both their genetics and their environments.
Nature and nurture act together to produce someone who shows little remorse for others, in the case of psychopathy, or who strategically manipulates people, a la Machiavellianism.
Studies have examined these relationships at a small scale, but the population-scale studies that could firm up the link are less common.
While genetic studies based on large datasets do show the ways in which our genes predispose us to dark traits, studying the environmental components is more difficult, as the variables can differ so widely as to make comparisons unhelpful.
But a study, published in 2025 in the journal Proceedings of the National Academy of Sciences by University of Copenhagen psychologist Prof Ingo Zettler and coauthors, gets around this.
How? By zooming out to encompass countries all over the world and using data on social conditions that are general enough to exist nearly everywhere, to some degree.
Their approach enabled a new look at a perennial question: Why do people do bad things?
The dark factor
In a twist of fate, the research paper was in part made possible by a shared global interest in the darker side of personality. In 2018, Zettler coauthored a study proposing the “dark factor” of personality.
It shares many similarities with the Dark Triad, though it’s a distinct metric, he says.
“The dark factor is the common core of all dark traits like those in the Dark Triad,” Zettler says.
That study attracted a lot of interest, so the researchers put the associated survey online where anyone could take it. The questions reflect a range of self-serving, vengeful and remorseless attitudes.
Sample statements and questions include: “Payback needs to be quick and nasty”; “Why should I care about other people, when no one cares about me?”; and “I would be willing to take a punch if it meant that someone I did not like would receive two punches.”
As Zettler’s survey became more popular, his team began asking participants for permission to use their data in future research.
Now, around eight years later, there are around three million survey responses (of which they used 1.8 million for their study) from around the world – a global snapshot of the darkness inside all of us.
To better understand where that darkness comes from, Zettler and his coauthors looked to things that could be found in any country on Earth, using World Bank data to rank countries on an ‘aversive societal conditions’ (ASC) index that included statistics on corruption, homicides, inequality and poverty.
This gave them one number that represented, in essence, how good or bad life was in each place.
Then, they compared the two numbers across 183 countries and all 50 states in the US, looking to see if they were at all correlated.
Crucially, they looked at societal conditions from 20 years before their survey took place to attempt to isolate the effects of the environment on personality, rather than the other way around.
In the US states and the countries, Zettler says they found a small, but statistically significant correlation between higher scores on the ASC index of societal dysfunction and dark personality traits.
In other words, the worse off a society was, the more likely people were to display behaviours that were self-serving or callous.
Dark places, light places?
In the US, Nevada ranked highest for dark personalities, followed by New York, South Dakota and Texas. Lowest-ranked, or ‘lightest’, were Vermont (by a good stretch), Utah, Maine and Oregon.
While levels of dark traits were generally higher as social conditions became worse, there were several outliers: both Louisiana and Mississippi were significantly less dark than their ASC scores would suggest, while South Dakota scored high for dark traits even though social conditions were reasonably good.
In the US, at least, dark traits seem to cut across the political spectrum, belying some recent headlines. States that reliably vote liberal, like New York and California, sat near the top of the dark personality list right next to those that typically vote conservative like Texas and Nevada.
It’s the same at the lighter end of the spectrum as well, where liberal-voting Vermont and Maine can be found near conservative-voting New Hampshire and Alaska.
When it came to countries, the researchers found the same relationship between societal conditions and dark personality traits, albeit with more outlier countries.
Asian countries like China, South Korea, Japan and Myanmar all scored quite high on the dark personality test, though many ranked only in the middle on the ASC index.
Meanwhile, Scandinavian countries like Denmark, Finland, and Sweden occupy the bottom of both the dark personality and ASC indices.
Both the US and the UK are found toward the lighter and socially positive end of the spectrum, though the UK does score a little bit higher for dark personality traits.
They both sit near countries such as France, Belgium, New Zealand, Canada and Cyprus in terms of dark traits.
Other intriguing outliers in the researchers’ data include Zambia, which scored very low on dark traits despite scoring high on the ASC index, and Singapore, which scored high for dark traits and quite low for societal risk factors.
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Survival instincts
The obvious takeaway from Zettler’s research is that bad environments condition people to act badly. That may be true, but the real question is why?
Zettler argues that it’s about social norms. After all, if most people around you cheat on their taxes, you’re more likely to see tax fraud as a reasonably normal thing to do, even if it’s not the most moral thing.
If your friends are doing it, it can’t be all that bad, right?
“People have different norms. And they can then make justifications based on the norms quite easily that result in more bad behaviour,” Zettler says.
When bad behaviour is common, there can be a higher cost to not engaging in it yourself, too. If your neighbours are all cheating on their taxes, you may need to indulge in a little fraud yourself just to keep up with the Joneses.
Another way to think about the link between social conditions and personality is to view these traits as adaptations, says Prof Peter Jonason, an evolutionary psychologist at VIZJA University in Warsaw, Poland.
“There are conditions in the world that generate ways of behaving that are optimised for those conditions,” Jonason says. In other words, there’s no payoff for being unkind or selfish in an equal, considerate society, and there may even be downsides.
But “it makes sense that in a competitive space, in a dangerous space, people should be more competitive, more risk-taking,” he says.
Jonason sees the three Dark Triad traits – psychopathy, narcissism, and Machiavellianism – as separate strategies in the pursuit of the same goal, which is to acquire resources.
A psychopath may bully others into getting what they want, a narcissist uses popularity, while Machiavellians use influence to achieve their goals.
In this view, the environment helps dictate the most successful strategy, pushing more people to display elements of a given personality trait.
In his own research, Jonason has examined the three components of the Dark Triad and their links to socioeconomic conditions, finding telling differences between the environments associated with each trait.
In a 2016 study, Jonason and his coauthors found that narcissism was actually associated with good socioeconomic conditions as a child, while Machiavellianism was associated with an upbringing that was privileged but unstable.
Psychopathy, by contrast, was associated with a harsh, stressful childhood.
Jonason says findings like these are evidence that we tune our personalities to our environments, based on signals received even very early in life, to yield the best outcomes for ourselves.
Whether those personality traits are good or bad, in this view, is less relevant – what matters is that they work.
It’s a dynamic that Prof Jonathan Schulz, behavioural economist at George Mason University, in the US, also saw in his research on honesty around the world.
He and his colleagues had participants roll a die and gave them rewards if they rolled certain numbers. The researchers couldn’t see the dice, so they had to rely on what the participants told them.
But, based on statistical probability, they could estimate in general whether people were lying or not.
“What we find is that countries that score higher on corruption indices, and higher on other measures that capture the prevalence of rule violations in those countries, you also see that people, on average, behave more dishonestly,” Schulz says.
“If you’re in a country where […] other people might cheat you more frequently, an adaptive strategy is also to be more dishonest in situations where you get an advantage,” he continues.
In a different light?
Though studies like the one Zettler recently carried out are illuminating, they do have their limitations. The first is simply the difficulty of gathering datasets that are both large and sufficiently representative of the places they come from.
For example, while Zettler’s roster of survey participants was almost two million strong, the authors were unable to fully assess who those responses came from.
Survey respondents could be predominantly upper class or urban or, as is likely, more interested than the average person in taking personality tests.
Another issue in large, global studies is what’s lost in translation, both linguistically and culturally.
In Zettler’s study, for example, Asian countries tended to score particularly high for the dark factor of personality, something that other studies don’t necessarily replicate.
In a different study coauthored by Jonason assessing Dark Triad traits in 49 countries, for example, only China showed up in the top four countries for any of the Dark Triad traits, and only for one of them.
While the reason for the disparity isn’t clear, it may be that things like narcissism or psychopathy are defined differently across cultures or perhaps are seen less negatively.
Schulz notes that things like selfishness can depend on the context. For example, nepotism – or prioritising the interests of your family first – might read as more virtuous in some cultures than others.
Machiavellianism may make for stronger, more capable leaders (albeit ones less likely to be fair and just), characteristics which may be desirable in times of strife or unrest.
Meanwhile, some of the most interesting insights from such large-scale studies of personality traits may lie at a slightly deeper level of analysis.
Jonason says that breaking participants out by gender has been particularly fruitful in his research. In a comparison of levels of narcissism between Turkey and Australia, for example, he says he found that men were about equally narcissistic in both places.
But women were significantly less narcissistic in Australia, potentially because the relative benefits of looking out for yourself are so much smaller there, he thinks.
In his study comparing the Dark Triad in 49 countries, Jonason also found differences in how the three personality traits correlated to societal factors.
In that paper, only narcissism was positively related to things like corruption and gender inequality, while psychopathy and Machiavellianism were unrelated to measures of societal health.
Machiavellianism, in fact, seemed to increase as gender equality went up, something Jonason and his coauthors suggest may result from a link between institutional complexity (where Machiavellians thrive) and the kind of societal development that also promotes gender equality.
Towards the light
Though Zettler acknowledges his study has some limitations, he says its ability to sum up dark personality traits clearly, as well as its size, nevertheless make its findings useful.
One of the most obvious questions, given the link between societal unwellness and dark personalities, is whether that relationship can be run in reverse.
Does making society better yield better humans?
Zettler says the theory holds up: make the environment more stable and more equitable, and people should behave more fairly and unselfishly. The study simply observed correlations, however, so it couldn’t examine the effects of changes, he says.
If true, that means we could break a fundamental feedback mechanism that may be at play in societies around the world in which bad conditions lead people to act badly, which in turn causes conditions to become worse.
It’s “a fundamental challenge,” Jonason says.
But the personality traits that dictate how we view and interact with the world are typically locked in relatively early – Jonason says by age 10 or so – meaning our window for creating change in people’s lives may be short.
Nevertheless, there may be hope. Schulz says that in research he’s conducted on cooperation there was a marked difference in how cooperative people wanted to be and how cooperative they felt they could be.
Comparing the United States to Morocco, he says he found that people in both places wanted to cooperate fairly at about the same rates. But in Morocco, they were less likely to believe the other person would be fair, leading them to be less cooperative as a protective measure.
“At the societal level, that can make a big difference,” Schulz says.
Change, after all, also starts from within.
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