Class breaks are good for all involved. They help people to go to the bathroom, get a drink, and just rest the brain for a few minutes. They also allow the brain a break to go over what it has been trying to process. Class breaks also allow the children to socialize in a less structured environment. This helps develop social skills which help with collective group development.
Kids need class breaks to take a minute and collect themselves. They need to let out that stress and pent up energy, it helps to encourage a better environment for learning. This way hyper students will be able to run and get rid of the energy and behave better in class.
Yes, class breaks contribute to a child's collective group development, because collective group development is not that important for a child. A child needs to learn to do more than follow the group. Spending time away from the group helps the child learn prospective. They can learn when peer pressure is a good thing and when it is a detriment.
Breaks during the school day are necessary for childrens' collective group development. Recess and similar breaks encourage students to interact and play with each other, which is always a positive thing. Without a doubt, these breaks contribute to a child's development in invaluable ways that people cannot and should not ignore.
I do not think that class breaks help create a collective group identity. I think that people tend to associate and want to be around people their own age or maturity level and class breaks contribute to that. It is a symptom of correlation, but not causation. Kids just want to hang out with like minded peers.