David Elkind is yet another demagogue engaging in faith-based science. Sweeping generalizations about any group of children larger than one borders on criminal negligence. The wide range of ages, genetics and environments any group of children represent is a value that defies any unit of measure. I really don't this guys help with my children. In fact, I resent having to work around some one like this just to ensure my children have a "constructive and joyful" experience at recess or in life.