Some kids engage at the right amount. Some too much. What about the kids who withdraw?
It is my thought-out position that, generally, kids who withdraw from interacting in a CI class have a reason to do so.
We all know that kids withdraw in traditional textbook classes from pure boredom. But when things are interesting (and they always are in a properly run CI class), then there is reason to respect the withdrawal of the kids in CI classes as more serious.
If we were to videotape hundreds of CI classes vs. hundreds of grammar classes we would see much more varied observable non-verbal authentic engagement in the CI classes than in the grammar classes. One thing is certain in CI classes – kids are listening more than they appear to be.