Nature vs. nurture has long been up for debate, and new research has put another tick in one particular camp.
A huge international study has found a link between how difficult a country’s living conditions are and how common certain dark personality traits become among its people. Traits like narcissism, manipulation, and a lack of remorse toward others seem to be shaped, at least partly, by the environment someone grows up in—and that’s not all researchers discovered.
Scandinavia and parts of Asia sat at opposite ends of the scale.
Countries like Denmark, Finland, and Sweden landed firmly at the calmer end of the results, pairing stable, fair social conditions with low average scores for dark personality traits. Several Asian countries, including China, South Korea and Japan, told a different story, scoring surprisingly high for dark traits despite only middling scores on the underlying measure of social hardship.
A handful of countries broke the pattern entirely. Zambia scored remarkably low on dark traits despite facing tough social conditions, while Singapore scored high for dark personality traits despite comparatively low levels of everyday hardship. Both the US and UK sat toward the calmer, more socially stable end of the spectrum overall, though the UK scored slightly higher for dark traits than its American counterpart.
Nevada topped the list within the United States.
Breaking the data down by individual US state, Nevada scored highest for dark personality traits, followed by New York, South Dakota and Texas. Vermont sat at the opposite end by a wide margin, followed by Utah, Maine, and Oregon.
The pattern didn’t split along political lines the way you might expect. Liberal leaning New York sat close to conservative leaning Texas near the top of the rankings, while liberal Vermont and Maine turned up near conservative leaning New Hampshire and Alaska close to the bottom.
Researchers built a single measure to score every country.
To make comparisons possible across such different places, the research team combined World Bank data on corruption, violence, inequality, and poverty into a single number for each country and US state, reflecting how difficult everyday conditions were there overall. This got compared against personality data collected from an online test measuring what’s known as the dark factor, essentially the shared core running through traits like psychopathy, narcissism and manipulative behaviour.
Close to two million survey responses from around the world went into the final analysis. Crucially, researchers compared personality scores against social conditions from twenty years earlier, a deliberate choice that helped separate cause from effect and made it more likely that tough environments were shaping personality, rather than the other way around.
Tough environments seem to reward selfish and manipulative behaviour.
An evolutionary psychologist based in Poland suggests these traits work as adaptations, strategies people develop to succeed within whatever environment they happen to grow up in. In a fair, cooperative society, being selfish or manipulative simply doesn’t pay off, but in a harsher, more competitive one, those same traits can become useful tools for getting ahead.
Research into childhood backgrounds supports this idea. Narcissism tended to develop in children raised with solid financial security, Machiavellian traits often emerged from a privileged but unstable upbringing, and psychopathy was more strongly linked to a harsh, stressful childhood overall.
Social norms may explain why bad environments spread bad behaviour.
The study’s lead researcher points to social norms as a big part of the explanation too. If cheating or dishonesty feels common within your surrounding community, it becomes far easier to justify doing the same thing yourself, even while knowing it isn’t strictly the right thing to do.
There’s a competitive pressure at play as well. If people around you regularly cut corners to get ahead, choosing not to do the same can put you at a real disadvantage, creating pressure to match everyone else’s behaviour just to keep up.
A dice game revealed how corruption shapes everyday honesty.
Separate research involving a simple dice rolling game, where participants earned rewards for reporting certain numbers, found a clear pattern. In countries scoring higher on corruption indexes, people were statistically more likely to lie about their results to claim a reward they hadn’t actually earned.
The researcher behind this study describes it as a reasonably rational adaptation to a dishonest environment. If you expect people around you to cheat you regularly, behaving a little more dishonestly yourself becomes a logical way to protect your own interests within that same system.
These studies come with real limits worth understanding.
Large-scale surveys like this one inevitably struggle to fully capture who’s actually responding. Participants may skew toward people who are more urban, more educated, or simply more drawn to taking personality tests in the first place, which could shift the overall results in ways researchers can’t fully account for.
Cultural and language differences complicate things further. Traits like narcissism or selfishness may be understood, or judged, quite differently depending on cultural context, which could partly explain why some countries scored unexpectedly high or low compared to other research covering similar ground.
Gender differences added another layer to the findings.
Breaking results down by gender uncovered some telling patterns, too. Comparing narcissism levels between Turkey and Australia, men scored about equally in both places, but women in Australia scored noticeably lower, possibly because looking out only for yourself carries fewer advantages in a more equal society.
A separate comparison across 49 countries found that narcissism specifically was linked to corruption and gender inequality, while psychopathy and Machiavellianism showed no clear connection to those same measures. Oddly, Machiavellian traits actually increased as gender equality rose, possibly because the kind of complex institutions where manipulation thrives tend to develop alongside broader social progress.
Personality traits form early, but there’s still room for hope.
Personality traits tend to become fairly fixed by around the age of ten, meaning the window for shaping someone’s behaviour through their environment is limited once childhood has passed. That’s a real challenge for anyone hoping to reverse this pattern on a large scale.
Even so, separate research into cooperation offers some encouragement. People in different countries generally wanted to cooperate with each other at similarly high rates, but in places with lower trust, people expected others to behave unfairly and became more defensive as a result. This suggests that rebuilding trust within a society, even gradually, could help push behaviour in a more positive direction over time.
