[NonValueAdded]

That seems counter-intuitive; how can earlier social mixing hurt social development?

[Cathy]

Negative social interaction. Kids pick up some of their worst traits at school, and if they are stuck in preschool and daycare most of the time their parents have very little influence over their behavior.

[Born to Conserve]

"That seems counter-intuitive; how can earlier social mixing hurt social development?"

How can premature birth hurt physical development?

[ladiesview61]

"That seems counter-intuitive; how can earlier social mixing hurt social development?"

I see what you mean..but maybe some kids, especially shy little ones, might be so overwhelmed with all of the activity and noise, that they go into a shell. I've seen it with my own children. The oldest and youngest did very well in a pre school, but the middle guy was way too overwhelmed, so we took him out and kept him home until he was ready for kindergarten. Thankfully, they're all pretty well adjusted teenagers now..no problems with social development, that's for sure.

[NathanR]

Because they are picking up bad habits from other children, instead of good habits from adults.

It probably works best, when it is the adults with the bad habits, and children are picking up better habits at the preschool.