Nevada has landed at the top of a new national ranking measuring so-called dark personality traits, according to a University of Copenhagen study that scored all 50 states on a scale built to capture self-interested and antagonistic tendencies. The state posted a D-score of 2.26 out of 5, edging out New York, Texas and South Dakota by just a few hundredths of a point, while Vermont came in lowest nationally at 1.96.
The study, led by University of Copenhagen personality and social behavior professor Ingo Zettler and published in the Proceedings of the National Academy of Sciences in May 2025, drew on personality survey responses from roughly 144,600 voluntary U.S. participants as part of a broader global dataset of 1.8 million responses spanning 183 countries, according to Las Vegas Weekly. Nevada's sample included nearly 1,600 participants, compared with just 347 in Vermont. The Dark Factor, or D-factor, concept itself traces back to a 2018 framework Zettler and collaborators proposed in Psychological Review, describing D as the general disposition to maximize one's own interests even at others' expense — the common thread underlying traits like narcissism, psychopathy, Machiavellianism, sadism and spitefulness.
How Researchers Built the Adversity Score
To test whether environment shapes these traits alongside genetics, Zettler's team cross-referenced each state's D-score against an Aversive Societal Conditions Index built from corruption, income inequality, poverty and violence data. Poverty carried the largest influence on the index, with corruption weighted less than half as much as poverty, inequality and violence combined, the researchers said, per the same account from Las Vegas Weekly. Zettler explained that combining four variables rather than relying on any single measure helped reduce statistical noise.
That societal-conditions data, notably, was pulled from 2000 to 2004 — a snapshot Nevada has since outgrown by nearly one million residents, per the outlet's reporting. Nevada posted an Aversive Societal Conditions score of just 43 out of 100, ranking it below average nationally on societal hardship even as it led the country in D-score. Louisiana, by contrast, recorded the nation's worst societal conditions score but landed only near the middle of the D-score rankings, underscoring that the two measures don't move in lockstep.
A UNLV Psychologist Urges Caution
Stephen Benning, a UNLV associate psychology professor and psychopathy researcher, told the outlet the narrow spread separating U.S. states — just three-tenths of a point between Nevada and Vermont — may carry limited real-world impact. Benning also said the “dark personality” framing itself risks sensationalizing the findings and stigmatizing the broader field of research. Still, he agreed that poor societal conditions may help shape dark personality traits, noting that poverty and trauma can influence genetically predisposed characteristics such as psychopathy.
Benning pointed to Nevada's mental healthcare shortages as a compounding factor, saying a lack of access may make it harder for antagonistic people to manage negative emotions. That concern echoes a separate report describing Nevada as the worst state for mental health.
Poverty and Housing Pressures Persist
Nevada's official poverty rate stood at 11.6% in 2024, or 374,033 residents below the federal poverty threshold, according to U.S. Census Bureau data reported by USAFacts.
Housing costs add another layer of strain. Hoodline has reported on Nevada's housing affordability challenges.
Global Comparisons and Open Questions
Zettler's team also built a global version of the adversity index using World Bank data, cross-checking results against separate press freedom and gender inequality measures. China posted the highest national D-score at 2.86, while Sweden recorded one of the lowest globally at 1.95, according to Newsweek's reporting on the study.
Researchers were careful to frame the findings as correlation rather than proof of direct causation. Zettler suggested that certain societal conditions might attract certain kinds of people to a place like Nevada in the first place, rather than shaping their personalities after arrival, and both he and Benning declined to draw a firm line between the state's social conditions and its D-score. Benning has separately studied fearless dominance — a low-fear, high-confidence trait tied to risk-taking and social boldness — and said it is not strongly associated with gambling broadly, though it might be overrepresented among people drawn to face-to-face table games. Zettler added that improving quality of life could theoretically affect how antagonistic traits develop over time, though he said strong supporting research on that question doesn't yet exist.
