Human Lie Detector: The #1 Sign They’re Lying To You, Catch Liars Instantly! | Dr Leanne ten Brinke
Episode of The Diary Of A CEO with Steven Bartlett · September 7, 2026 · 1 h 44 min
Psychologist Leanne ten Brinke tells Steven Bartlett how to detect lies, explains the Dark Tetrad of personality traits, and offers rules for dealing with toxic people.
Summary
Steven Bartlett interviewed psychologist Leanne ten Brinke about her research on deception and so-called dark personality traits, drawing on her book Poisonous People. Ten Brinke described research showing observers can glean some sense of psychopathy from five-second clips, her PhD work on people who publicly pleaded for missing relatives they had killed, and the cues she considers reliable signs of lying: sparse or ambiguous detail, few verifiable details, and visible cognitive effort. She argued that gaze aversion is not a valid cue and that asking open-ended follow-up questions is the best lie-detection tool.
She then explained the Dark Tetrad of psychopathy, Machiavellianism, narcissism and sadism, stressing that these traits lie on a continuum, distinguishing grandiose from vulnerable narcissism, and citing prevalence estimates of about 1% for clinical psychopathy, 2–5% for narcissistic personality disorder, and roughly 10% of people agreeing with dark-trait items. She described roughly equal genetic and environmental contributions, the role of cold or abusive parenting and child overvaluation, brain differences in the prefrontal cortex and amygdala, and limited prospects for change.
Ten Brinke also discussed her research finding that being lied to reduces feelings of closeness, and her work with Dacher Keltner showing psychopathic traits were associated with less influence in government and lower hedge-fund returns. After analyzing mock dating profiles for red flags, she outlined seven rules for dealing with dark personalities, including clear boundaries, rewarding rather than punishing, emphasizing common identity, and avoiding face-to-face negotiations, as well as discussing gaslighting. She closed by arguing that the idea that success requires ruthlessness is a lie.
Chapters
- 1:47
Why study dark traits
Ten Brinke explained that she hopes understanding deception and dark personalities will make people less cynical about human nature.
- 4:06
Spotting psychopathy in seconds
She described research on thin-slice judgments of psychopathy and the Duchenne smiles and hand gestures of high scorers.
- 7:05
Deceptive pleaders and cues to lying
Ten Brinke discussed her PhD on false public pleas and the three most reliable signs of deception.
- 13:46
How to catch a liar
She explained that people detect lies at about 54% accuracy and that open-ended follow-up questions work better, with a role-play about cheating.
- 20:29
The eye contact myth
Ten Brinke argued gaze aversion is not a valid cue to deception and harms neurodivergent people and some cultures.
- 21:53
The Dark Tetrad explained
She defined psychopathy, Machiavellianism, narcissism and sadism, including grandiose versus vulnerable narcissism.
- 34:48
Myths, prevalence and origins
Ten Brinke debunked the violent-psychopath myth and discussed prevalence, genetics, parenting and brain differences.
- 46:06
Can dark traits change?
She discussed limited treatment effects, agreeableness challenges, and long-term persistence of psychopathic behavior.
- 51:32
Lies, closeness and warmth
Ten Brinke described findings that being lied to reduces connection and discussed warmth, competence and trust.
- 59:58
Dark traits and success
She reported that psychopathy predicted less government influence and lower hedge fund earnings, and that narcissists impress early but disappoint.
- 1:04:42
Red flags in dating profiles
Ten Brinke analyzed mock dating profiles and listed early warning signs of dark traits.
- 1:13:55
Seven rules for dark personalities
She outlined strategies including boundaries, withholding power, rewards, common identity, detection and text-based negotiation, with a digression on gaslighting.
- 1:37:54
Three mistakes and the outsized 10%
Ten Brinke described common mistakes and argued a small minority causes disproportionate harm.
- 1:41:11
The great lie about success
She answered the closing question by rejecting the idea that ruthlessness is necessary for success.
Key points
What was said, by whom, with the exact words. Timestamps jump to the moment.
- Leanne ten Brinke
Ten Brinke said research shows people can get a kernel of truth about how psychopathic someone is in about five seconds.
“you can get a kernel of truth about someone's personality, the extent to which they're psychopathic, in about five seconds”
- Leanne ten Brinke
Ten Brinke reported that four cues predicted with about 90% accuracy which TV pleaders were lying, though a later replication found more modest effects.
“we were able to use four different cues, so two verbal and two nonverbal, to predict with about 90% accuracy who was lying”
- Leanne ten Brinke
Ten Brinke said the most consistent difference between liars and truth tellers is that liars give fewer details.
“the most consistent effect we have that differentiates people who are telling the truth from people who are lying is the amount of detail that they give”
- Leanne ten Brinke
Ten Brinke said people detect lies at only about 54% accuracy on average.
“People are not very good at detecting these lies or really any kind of lies. On average, people perform at about 54% accuracy”
- Leanne ten Brinke
Ten Brinke argued that learning to ask good, unanticipated questions is an essential tool for detecting lies.
“learning how to ask good questions is actually a really kind of essential tool for detecting lies”
- Leanne ten Brinke
Ten Brinke said simply judging how verifiable a statement is beats trying to combine many unreliable cues.
“it is better to focus on one cue that works than to try to put together all of these little cues that mostly don't work at all”
- Leanne ten Brinke
Ten Brinke said there is no research supporting the common belief that sketchy eye contact signals lying.
“They will say sketchy eye contact. And there's no research to suggest that that is true”
- Leanne ten Brinke
Ten Brinke argued that dark traits exist on a continuum, so it is more accurate to describe people as having high levels of a trait than labeling them narcissists.
“I think it's more accurate to say they have relatively high levels of narcissism or psychopathy or whatever the case is”
- Leanne ten Brinke
Ten Brinke said about 10% of people on average agree with self-report items measuring dark traits.
“if you just look at the people who on average agree with the items that we use to self-report, assess these traits, it's about 10 percent of the population”
- Leanne ten Brinke
Ten Brinke said variation in psychopathy and narcissism is about half genetic and half environmental.
“the variation in someone's score on that personality trait is about 50% genetic and about 50% environmental”
- Leanne ten Brinke
Ten Brinke said early intervention training parents in warm, responsive parenting can reduce development of psychopathic traits in children.
“early intervention with kids is. really can help reduce the likelihood of them developing high levels of psychopathic traits as they grow older”
- Leanne ten Brinke
Ten Brinke reported that people feel less close to conversation partners who lie to them, even without suspicion.
“we keep finding these pretty small but consistent effects that people feel less close to their interaction partner when someone is lying to them”
- Leanne ten Brinke
Ten Brinke said her research with Dacher Keltner found psychopathy was linked to less government influence and lower hedge fund earnings.
“consistently, we found that high levels of psychopathy was associated with less influence in government. It was also associated with making less money as a hedge fund manager”
- Leanne ten Brinke
Ten Brinke argued that narcissists seem like leaders because people confuse confidence with competence.
“the thing that can make narcissism look good at the outset is our confusion of confidence and competence”
- Leanne ten Brinke
Ten Brinke defined gaslighting as a pattern of denying someone's version of reality that functions as a control tactic.
“it's a pattern of denying someone's version of reality”
- Leanne ten Brinke
Ten Brinke recommended rewarding good behavior in people with psychopathic traits because they are reward-sensitive but not punishment-sensitive.
“people, particularly with high levels of psychopathy, very reward sensitive, but not very punishment sensitive”
- Leanne ten Brinke
Ten Brinke cited research showing people with dark traits obtained better deals in face-to-face negotiations than over text, advising text-based negotiation.
“whenever those negotiations occurred face-to-face, the person with the high level of psychopathic traits or any of these dark traits, they got a really good deal”
- Leanne ten Brinke
Ten Brinke said offenders with clinical psychopathy, about 1% of the population, account for about half of serious crime.
“offenders with clinical levels of psychopathy account for about 50% of all serious crime”
- Leanne ten Brinke
Ten Brinke argued it is a lie that success requires looking out for number one and displaying dark traits.
“one great lie we've all been told is that to be successful, you have to be in it for number one”
People
In the conversation
- Steven BartlettBritish entrepreneur and host of The Diary Of A CEO podcast
- Leanne ten BrinkePsychologist, director of the Truth and Trust Lab at the University of British Columbia, and author of Poisonous People
Discussed
- Scott LilienfeldAmerican psychologist whose research examined thin-slice judgments of psychopathy
- Dacher KeltnerAmerican psychologist and ten Brinke's collaborator on psychopathy and success research
- Ted BundyAmerican serial killer newly linked by DNA to a 1974 Utah victim
- Jussie SmollettActor convicted over a staged hate crime, who appeared at a Harlem Pride event
- Niccolò MachiavelliItalian Renaissance author of The Prince, namesake of Machiavellianism
- Bernie MadoffAmerican financier whose Ponzi scheme prompted ten Brinke's turn to business research
- Nathan HudsonPsychologist who studied agreeableness challenges to reduce dark traits
- Delroy PaulhusPsychologist whose study showed narcissists make strong first impressions that fade
- Tali SharotNeuroscientist who studied disagreement, previously a guest on the show
- Vanessa Van EdwardsBehavioral researcher, bestselling author, and founder of Science of People
Topics
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From the publisher
Are you dealing with a master manipulator? Learn how to identify the hidden red flags of liars, psychopaths and narcissists before they cause lasting damage. Dr. Leanne ten Brinke, a renowned psychologist and director of the Truth and Trust Lab at the University of British Columbia, breaks down the science of deception and toxic behavior. Drawing from her extensive peer-reviewed research and her eye-opening book, Poisonous People, she shares practical, evidence-based strategies to help you recognize dark personality traits and protect your mental well being. In this episode, she explains: ■ The Warning Signs: How to spot the early behavioral red flags of the "Dark Tetrad" (psychopathy, narcissism, Machiavellianism, and sadism) before you get hurt. ■ The Manipulation Playbook: The exact psychological tactics toxic individuals use to control and deceive others, including what gaslighting actually means. ■ The Lie-Detector Myth: Why relying on eye contact, fidgeting, and body language is actually a terrible way to catch a liar. ■ The Two Faces of Narcissism: How to identify the different types (including why one completely crumbles at the slightest criticism), and the devastating toll of working for a psychopathic boss. ■ Defense Strategies: Proven techniques to outsmart dangerous personalities, set ironclad boundaries, and dramatically improve your life. Chapters 00:00:00 Intro 00:02:21 Why This Research Into Psychopathy Matters 00:02:58 Why Psychopathy Is Getting More Attention 00:04:05 Can You Spot a Psychopath in 5 Seconds? 00:05:30 How Facial Expressions Reveal What People Really Feel 00:08:56 Can You Predict If Someone Is Guilty? 00:09:59 Three Signs Someone Might Be Lying 00:13:46 Can Anyone Learn to Spot a Liar? 00:20:29 Why the Eye Contact Myth Gets Body Language Wrong 00:21:53 Psychopathy, Narcissism, Machiavellianism and Sadism Explained 00:34:49 The Biggest Myths About Psychopaths Debunked 00:36:28 How Common Are Dark Personality Traits? 00:38:05 Are Dark…
Summary, chapters and key points were generated from the episode transcript on October 3, 2026. Quotes are checked word for word against the transcript.