http://www.universityofcalifornia.edu/news/article/7616
How Much Is Too Much
The report - "The Influence of Preschool Centers on Children's Development Nationwide: How Much Is Too Much?" - also examined whether long hours in preschool centers lead to diminishing returns in children's early development.
Most surprising, according to the researchers based at the University of California, Berkeley, and Stanford University, is that the social skills of white, middle-class children suffer- in terms of cooperation, sharing and engagement in classroom tasks - after attending preschool centers for more than six hours a day, compared to similar children who remain at home with a parent prior to starting school.
"The biggest eye-opener is that the suppression of social and emotional development, stemming from long hours in preschool, is felt most strongly by children from better-off families," said UC Berkeley sociologist and co-author Bruce Fuller.
