The Five-Second Kernel of Truth
People may form surprisingly informative impressions of dark personality traits from only a few seconds of behavior, according to research described by ten Brink. In studies involving short video clips of criminal offenders, psychology students rated traits such as callousness and manipulation after viewing as little as five seconds of an interview.
Those snap judgments showed some correlation with assessments from trained clinicians, although a brief impression is not the same as a reliable diagnosis of psychopathy or deception.
When ten Brink's lab partnered with Lilienfeld to code the same videos, two behaviors stood out. People higher in psychopathic traits flashed Duchenne smiles (genuine-looking smiles with telltale activation around the eyes) while saying strikingly hostile things, creating a strange emotional mismatch. They also used frequent hand gestures, which researchers call illustrators. Random observers picked up on these cues, even with almost no information to go on.
She cautions that personality exists across time and context, so more data across situations always yields better judgments.
Red Flags and Ember Flags in the Wild
- Embedded liesA long story dense with verifiable detail, then suddenly sparse and vague at the crucial part, like a prepared interviewee expanding freely on true tangents while going vague where the alleged lie lives.
- Asymmetric interruptionInterrupting often but refusing to tolerate being interrupted signals impulsivity and dominance, per ten Brink's early-warning list.
- Weirdly calmShallow emotional affect (no fear or concern where you'd expect it) links back to psychopathy, as does intense eye contact clinicians describe as peering into your soul.
- One interaction, one cautionShe treats self-promotion in a dating profile or job interview as an 'ember flag': worth storing, worth testing later with pointed questions about teamwork, but not enough for a personality verdict.
- The gaslighting lineArguing about facts is argument; denying someone's perception of their own experience (telling them they shouldn't feel what they feel) is what crosses into gaslighting, a control tactic people with these traits endorse in research.
The Myths We Bring to Lie Detection
The public's favorite lie-detection cue doesn't survive contact with the evidence. Ask people worldwide what signals a liar and they will say it's someone who can't look you in the eye, and, as ten Brink puts it, there is no research to suggest that's true. The stereotype is self-defeating anyway: because everyone knows it, liars simply control their gaze.
She adds that some people on the autism spectrum struggle with eye contact while telling the truth, and some cultures consider direct eye contact disrespectful, both leading to false accusations.
What actually works is detail. In her PhD research on people pleading on TV to find missing loved ones (some of whom had killed them) she and colleagues used four cues to predict with about 90% accuracy who was lying, though a replication attempt found more modest effects. The most consistent finding across her work: liars give fewer details, speak in tentative and ambiguous terms, and offer specifics that are hard to verify.
Liars also face increased cognitive load (inventing facts, avoiding contradictions, remembering the story for next time) which can surface as visible effort, slow speech, and furrowed brows.
The sobering baseline is that without training, people are barely better than chance: roughly 54% accuracy, about six or seven correct out of twelve videos in her lab's experiments. What helps more than watching for tells is asking better questions, open-ended, unanticipated ones. 'Tell me more about that' forces liars to invent details truth-tellers already have, and simply asking how verifiable a statement was beats every fidget-based algorithm.
The Dark Tetrad and Its Outsized Footprint
The so-called dark triad is now a tetrad: psychopathy, Machiavellianism, narcissism, and the newest addition, sadism. What the four share is callousness, manipulativeness, and hostility toward others. Psychopathy brings superficial charm, shallow emotion, impulsivity, and rule-breaking; Machiavellianism adds strategic, three-dimensional-chess manipulation in pursuit of power; narcissism contributes entitlement and relentless self-focus; sadism means taking pleasure in others' pain, from sexual homicide down to everyday online trolling.
The numbers are striking because the traits exist on continua. Ten Brink cites clinical psychopathy at roughly 1% of the population, narcissistic personality disorder at 2 to 5%, and (using self-report questionnaires) about 10% of people who on average agree with items measuring these traits. The 1% with clinical psychopathy, she notes, account for about 50% of all serious crime: an outsized footprint.
She also pushes back on the movie villain image (most people with high psychopathy are not violent) and notes men score higher on average than women across these traits, though with substantial overlap.
Where does it come from? Roughly half genetics, half environment, per the research she cites. Cold, uncaring, or abusive parenting raises the risk, and for narcissism there's an unsettling twist: a longitudinal study found that the more parents told their children they were special and better than other kids, the more narcissistic (but not more self-esteeming) the children became later.
The silver lining is early intervention: parent training built on warmth and rewards, rather than punishment, can reduce the likelihood that children with early callous-unemotional signs develop high psychopathic traits.
The 'Successful Psychopath' Who Isn't
The persistent cultural claim is that these traits pay off, that ruthless charm wins promotions, elections, and fortunes. Ten Brink went looking for proof. With Dacher Keltner, she studied whether psychopathic traits could increase influence in government and earnings as a hedge fund manager, two hyper-competitive contexts where backroom tactics and risk appetite might plausibly shine.
The results ran the other way: higher psychopathy was consistently associated with less influence in government and less money in hedge funds.
Narcissism and Machiavellianism show a subtler pattern: they can help people rise in rank and earn more, per some research she cites, but the teams underneath suffer. In a Del Paulhus study, narcissistic students dazzled in first group meetings (confident, leadership-hungry) then over the term were seen as hostile, lazy, and difficult.
The initial appeal, ten Brink argues, rests on our confusion of confidence with competence: saying you can do something convincingly is not the same as doing it. High-psychopathy managers talk a great game but report being terrible bosses who bully subordinates and create stress that follows their teams home.
Living Alongside What You Cannot Cure
Can these people change? Ten Brink's answer is that some change is possible, with heavy emphasis on some. Incarcerated offenders with clinical psychopathy are rarely motivated to change (the people they hurt are others) though consistent cognitive behavioral therapy can reduce recidivism. In her book, she cites a study of more than a thousand people who knew psychopathic individuals long-term: 93% said behavior after age 50 was just as bad or worse than before.
For lower levels of the traits, Nathan Hudson's agreeableness challenges (daily smartphone prompts to give compliments and buy coffee for strangers) did lower self-reported dark traits over four months among those who followed through.
That reality forces a management playbook rather than a cure. Ten Brink's rules include making boundaries explicit, since research shows rules reduce selfish behavior even when they aren't guaranteed to hold; withholding power over others; using the carrot rather than the stick, because people high in psychopathy are reward-sensitive but their brains process punishment poorly; and emphasizing common identity, since narcissists take negative feedback less angrily from those they believe share something with them.
One unexpectedly practical move: avoid face-to-face negotiations. In a University of British Columbia study, dark-trait negotiators dominated in person but lost their edge over text, which also leaves a written record and buys thinking time.
The three mistakes she flags are believing there's nothing you can do, assuming these people share your inner experience, and waiting for them to change. Behind all of it is a question of arithmetic she wants readers to hold onto: if about 10% of people carry elevated levels of these traits, 90% are, by her framing, good and kind and honest.
The small minority causes hugely outsized harm, and learning to mitigate that damage (at work, at home, in the family group chat) may, she argues, dramatically improve daily life.