ReThinking: How to spot psychopaths and narcissists, with Leanne ten Brinke

What It Covers

Social psychologist Leanne ten Brinke joins Adam Grant to examine the dark tetrad — psychopathy, narcissism, Machiavellianism, and sadism — covering how to detect these traits through behavioral cues, why roughly 10% of people qualify as poisonous, and concrete strategies for managing dark personalities at work and home.

Key Questions Answered

• •Psychopathy detection via contagion: People with high psychopathic traits fail to yawn in response to others yawning — a measurable empathy deficit rooted in diminished automatic emotional contagion. They retain cognitive empathy (understanding others' thoughts) but lack affective empathy (catching others' feelings), which researchers describe as knowing the words but not the music of emotion.
• •Behavioral red flags in conversation: An interpersonal psychopathy checklist developed by David Causon identifies specific signals: frequently interrupting others while refusing to be interrupted, ignoring stated conversational boundaries, using complex vocabulary incorrectly to impress, and displaying mismatched emotions — such as smiling broadly while speaking hostile or angry words — detectable in as little as five seconds.
• •Dark traits in leadership — accurate base rates: CEOs are roughly three times more likely than the general population to have clinical psychopathy (3% vs. 1%), but 20% of incarcerated individuals meet that threshold, meaning psychopathy far more reliably predicts prison than executive success. Ninety-seven percent of CEOs are not psychopaths, and dark-trait politicians measured on C-SPAN proved less influential, not more.
• •Managing dark colleagues without manipulation: Two evidence-backed tactics reduce conflict with dark-trait coworkers: establish minimal common ground (shared team, birthday, or interest), which reduces narcissistic blowups to negative feedback, and reframe feedback as questions rather than statements. Asking "What do you think about changing the report this way?" feels less threatening to dominance than direct correction.
• •Personality change through agreeableness challenges: Nathan Hudson's 16-week study showed that participants who received daily behavioral prompts — expressing gratitude to unfamiliar people, performing kind acts, perspective-taking when annoyed — reported measurable increases in agreeableness and reductions in dark traits. Personalities are stable but not fixed; consistent, structured behavioral practice shifts them over time.