Google's Project Aristotle describes "psychological safety" as what matters the most for teams to effectively work together. The study cites another, Psychological Safety and Learning Behavior in Work Teams, where psychological safety is defined and its impact in the workplace studied. In the latter, team psychological safety is defined as follows (page 6, emphasis mine):
a shared belief that the team is safe for interpersonal risk-taking.
(...)
Team psychological safety involves but goes beyond interpersonal trust; it describes a team climate characterized by interpersonal trust and mutual respect in which people are comfortable being themselves.
The challenge, I feel, is to ensure people are comfortable being themselves while also behaving professionally. How to address individual misbehaviours while preserving the team psychological safety?
Here is a concrete example with a colleague in my team. He's one of the senior engineers in the team and often behaves similarly to what is described in the opening paragraph of this blog post:
Most folks have worked with someone who thinks they’re never wrong. In each discussion, they lean in, broaden their shoulders and breach their way into the role of the decider. They’ll continue debating until their perspective wins the day or time runs out. They are often right, but right in a way that sucks the oxygen out of the room.
When I tried to bring this to his attention, he replied that he felt uncomfortable changing because he wouldn't feel like he was being himself anymore. The way I addressed this was saying who he is cannot get in the way of other team mates feeling uncomfortable discussing any topic with him. He disagreed and felt he "needed to be convinced" (his exact words) before he could change his attitude. We had reached a deadlock and that was end of the conversation.
What do suggest as next steps in the above case?