First, I think people get to know each other through achieving a certain level of openness. But appropriate self-disclosure can help to reveal something of the person behind the name and position. I believe this helps. And someone has to break the ice. Second, I think a climate of mutual enquiry is much more helpful than one of competitiveness.
Some people thrive in a hothouse of belligerence, but others are rendered entirely quiet.
Combining openness with support seems to work well for mor people, including some of those who may otherwise lurk in the shadows. Third, some years ago I heard Reg Revans speak about action learning. One of the things he said stuck in my mind as particularly relevant. He said that action learning groups work when people are able to express their ignorance or confusion about what they are trying to do. They are then better able to learn, and to help each other to do so.