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788: How to Work with Poisonous People, with Leanne ten Brinke
Brief
Poisonous people — those who score high on the "dark tetrad" of psychopathy, Machiavellianism, narcissism, and sadism — are common enough that leaders must learn how to manage them. In episode 788 (Coaching for Leaders, 2026-06-22), host Dave Stachowiak and guest Leanne ten Brinke (UBC, Truth and Trust Lab) map the landscape: clinical psychopathy is rare (~1%), but another 10–20% of people show elevated dark traits that make them callous, manipulative, and antagonistic. They discussed research demonstrating troubling organizational effects — Dave cites a study by Paul Babiak, Craig Neumann, and Robert Hare that found about three times as many people with psychopathy in senior management as in the general population — and Leanne explained why those people can be promoted (charisma, confidence, perceived creativity) despite often failing to follow through on work. They agreed personalities change slowly and rarely without the person’s motivation, so the practical question is how to manage relationships rather than fix the person.
The bulk of the conversation presents evidence-based rules for working with poisonous people. Leanne recommends making norms explicit (write boundaries, policies, and job expectations into email or Slack) because high-dark-trait individuals exploit unwritten social rules; she described an experiment where explicit rules led psychopathic participants to distribute money fairly. In negotiation, her UC Berkeley research found dark-trait individuals do well in zero-sum bargaining but perform poorly at integrative trade-offs, so she advises designing win-win trades that align with what the person values (attention, money, dominance). Communication medium matters: with these individuals, avoid face-to-face conflict—use written channels to blunt charisma, create records, and buy time. Finally, Leanne highlights neurological differences: they’re less punishment-sensitive but reward-sensitive, so reinforce desired behavior (praise, raises, visible recognition) while avoiding giving them power over others. The episode ends by urging listeners to weigh sunk costs and family spillover effects, and to use these concrete tactics when staying in a role is necessary.
Why it matters
Leanne ten Brinke (associate professor, University of British Columbia; director, Truth and Trust Lab) defines "poisonous people" as those with elevated levels of the dark tetrad: psychopathy, Machiavellianism, narcissism, and sadism.
Key details
- Prevalence on a spectrum: Dave Stachowiak and Leanne noted ~1% of people meet clinical psychopathy thresholds, while an additional ~10–20% show a dark personality profile (traits on a continuum, not a binary).
- A study cited by Dave (Paul Babiak, Craig Neumann, and Robert Hare) found roughly three times as many people with psychopathy per capita in senior management positions than in the general population, suggesting real leadership implications.
- Leanne’s practical rule: make norms explicit — write boundaries and rules (email/Slack/policies). Experimental evidence she cites showed people high in psychopathic traits behave fairly when explicit rules and monitoring are present.
- Negotiation insight from Leanne’s UC Berkeley research: people high in dark traits extract more in distributive/zero-sum negotiations but perform worse on integrative (trade-off) bargaining; when both parties score high on dark traits, dyadic outcomes are particularly suboptimal.
- Communication medium matters: Leanne recommends avoiding face-to-face conflict with high-dark-trait individuals — use written channels (email/text) to blunt charisma, preserve evidence, and give yourself time to respond; she contrasted this with Juliana Schroeder’s general finding that in-person usually helps conflict resolution.