Leanne ten Brinke: Poisonous People

Leanne ten Brinke is an Associate Professor at the University of British Columbia, where she directs the Truth and Trust Lab. Her research investigates trust, deception, and dark personality traits across diverse populations—from incarcerated individuals to hedge fund managers and politicians. She reveals how dark personality traits shape our institutions and relationships, while offering practical strategies to recognize and counteract their harmful influence. Her book is titled Poisonous People: How to Resist Them and Improve Your Life (Amazon, Bookshop)*.

If you are a leader, you are going to deal with poisonous people. Sometimes they will show up as clients, sometimes your boss, sometimes your peers, and sometimes the people you manage. Regardless of where they show up, this conversation with Leanne will help you handle this tough dynamic.

Key Points

• Dark traits exist on a spectrum. While only 1% of the population rises to a clinical level of psychopathology, 10-20% of the population has a dark personality profile.
• There are many more people with psychopathy per capita in senior management positions than in the general population.
• Poisonous people generally aren’t interested in shifting their personality. As such, you will not change them. Given that reality, aim to better manage the relationship.
• Establish clear boundaries with poisonous people and put things in writing you might normally assume. Dark personalities are really good at exploiting unspoken norms.
• Find ways to create win-wins with poisonous people. They don’t do well with trade-offs, because they don’t like to lose anything.
• Avoid face-to-face negotiations with them. Their charm and charisma will win you over in the moment. Text-based dialogue will help you objectively negotiate better.
• Use the carrot instead of the stick. Reward good behavior when it happens (just not by giving them power over others).

Resources Mentioned

• Poisonous People: How to Resist Them and Improve Your Life by Leanne ten Brinke (Amazon, Bookshop)*

Interview Notes

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Related Episodes

• How to Handle a Boss Who’s a Jerk, with Tom Henschel (episode 164)
• How to Start Better With Peers, with Michael Bungay Stanier (episode 635)
• How to Show Up Authentically in Tough Situations, with Andrew Brodsky (episode 727)

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