Dr. Leanne ten Brinke’s research focuses on dark personality traits. She has just published a book providing guidelines on how to live and work with “poisonous people”.
Most people know someone like this: a friend who suddenly turns on you, a co-worker who smiles while undermining your work or a romantic partner who seemed so perfect until it all went sour.
While there are many words for such people, including bully, bad apple or simply difficult, personality researchers call them “dark tetrad”—people with narcissistic, psychopathic, sadistic or Machiavellian tendencies.
Dr. Leanne ten Brinke is an associate professor of psychology at UBC Okanagan and directs the Irving K. Barber Faculty of Arts and Social Sciences‘ Truth and Trust Lab. Her research focuses on psychopathic personality traits. She calls people high in dark tetrad traits “poisonous people” because they can have a broad, harmful influence on those around them. She recently published a book, Poisonous People: How to Resist Them and Improve Your Life.
She discusses the science behind the book, why recognizing dark personality traits matters, and how to lessen their influence.
What led you to this type of research?
I grew up in the small town of Antigonish, Nova Scotia. One day, my high school sociology teacher played a Nature of Things documentary on psychopathy, and I was immediately fascinated. I went to Dalhousie University in Halifax for my undergraduate degree. There, I volunteered at the Halifax Parole Office and attended weekly treatment sessions for sexual offenders in the community.
It was during one of those sessions that a parolee threatened me, implying that I might be next on his list of victims. That interaction turned out to be pretty pivotal in my career—I decided I would study psychopathic personalities, but not treat them. So, I later pursued a doctoral degree in experimental, not clinical, psychology. I’ve studied deception, dominance and dark personalities ever since.
Can you describe the red flags of a dark personality?
The dark tetrad of traits share a core of callousness, manipulation and antagonism. In other words, they tend to be hostile to other people.
Each trait has unique qualities, too. Psychopathy also involves impulsivity and rule-breaking behaviour. Machiavellianism is more strategic. They tend to use manipulation in pursuit of power. Narcissism involves grandiosity and entitlement, while sadism involves experiencing joy from others’ pain.
Our ability to understand someone’s personality tends to improve the more that we interact with them, but there can be early red flags. For example, highly narcissistic people are more likely to talk about themselves and be overly concerned with their appearance. Highly psychopathic personalities may use hostile or angry language while smiling, or be weirdly calm when others would show signs of stress.
It’s helpful to be aware of red flags, but also to treat your impression of their personality as a running theory that you can update with more evidence.
If someone has dark personality traits, can they change?
Common wisdom is that these traits—and personality, in general—are set in stone, but research in prison settings shows that people with clinical levels of psychopathy are less likely to re-offend after release if they take part in treatment.
In less extreme cases, taking on agreeableness challenges consistently over the course of 16 weeks can also reduce dark traits. Those challenges might include sending an encouraging text to a friend, listing three things you’re grateful for, or trying to take someone else’s perspective in an argument.
Consistency and follow-through are key. Change is slow, but we can all learn to turn down the dial on our dark traits if we commit to it.
How can someone cope with a poisonous boss, friend or co-worker?
When people with dark personalities become part of our workplaces, friend groups or families, they can have a poisonous effect. People with these traits are more likely to bully subordinates at work, leading to high stress and turnover. They are more likely to cheat on their romantic partners and tend to think that gaslighting in relationships is acceptable. In political contexts, candidates with these traits hurl more insults and increase polarization. In this way, one bad apple really can spoil the bunch.
To cope, put explicit rules in place about what behaviour is permitted and what is not. Setting boundaries doesn’t guarantee good behaviour, but research finds that people with psychopathic traits are less likely to break clear rules than the fuzzy ones we don’t write down or enforce. And when rules are broken, rewards can work better than punishment for shaping the behaviour of someone with psychopathy.
One other practical tip is to negotiate with a dark personality over text or email instead of face-to-face. Dark personalities lose some of their power of persuasion when reduced to written words on a page.
Of course, leaving safely may also be a wise option.
Is it possible to take back the power and control?
Absolutely. Dark personalities can seem confident and strong—qualities that align with our stereotypes of leadership. But research shows that narcissism, callousness and manipulation in leadership actually decrease performance. If we can learn to correct our false assumptions about what it takes to be a leader, we can reduce the damage caused by having dark personalities in power.
Another underrated aspect of taking back power is a simple mindset shift. A few bad apples can make us cynical about human nature as a whole, but the vast majority of people do not score particularly high on these traits. Don’t let a malevolent few distract you from the power of a benevolent majority.
