We teachers have been taught the importance of fostering a sense of safety in our classrooms. The "strong container" is Lakey's useful analogy for this.
He differentiates between comfort and safety. Learning involves discomfort. Learners must put themselves into unfamiliar situations and experiment with strange ideas. Their experiments may "fail". Of course, learning comes from analyzing such failures and trying again. We present our learners with opportunities, but they must decide to take the risks themselves. That's where the "strong container" comes in.
If I understand it correctly, a container is built of the group's goals and expectations. The facilitator makes sure that goals of the learning session are clear and that the group has an opportunity to negotiate ground rules (or norms). The facilitator then takes ownership of enforcing the norms, freeing the participants to focus on their own development. If these things are in place, then the container will be strong.
It's interesting to read about "enforcement" in a book based on a direct action approach! (Direct action is often associated with non-violence.) I agree with Lakey's use of the word, however. He says:
... participants have not entered a contract of mutual enforcement simply by agreeing to the ground rules. Their agreement is to live by the norms personally, not to enforce normative behavior on others.He points out that every group has a mainstream and margins and the mainstreamers are the ones who tend to "enforce". This can deny the voice of the margins. If the teacher owns the authority, it frees each individual to focus on his or her own contribution toward learning.
I've been thinking about this during class sessions now. I notice that containers aren't static. There are times when the room feels "warm", when people eagerly turn to each other to try new things. There are other times that feel "cool" and I sense that each person is in his or her own separate container.
(Note: post edited for clarification.)