Change in play, change in kids

Alix Spiegel in Old-Fashioned Play Builds Serious Skills(via Evo. Psych. discussion group):
"But during the second half of the 20th century, Chudacoff argues, play changed radically. Instead of spending their time in autonomous shifting make-believe, children were supplied with ever more specific toys for play and predetermined scripts. Essentially, instead of playing pirate with a tree branch they played Star Wars with a toy light saber. Chudacoff calls this the commercialization and co-optation of child's play — a trend which begins to shrink the size of children's imaginative space.

But commercialization isn't the only reason imagination comes under siege. In the second half of the 20th century, Chudacoff says, parents became increasingly concerned about safety, and were driven to create play environments that were secure and could not be penetrated by threats of the outside world. Karate classes, gymnastics, summer camps — these create safe environments for children, Chudacoff says. And they also do something more: for middle-class parents increasingly worried about achievement, they offer to enrich a child's mind.

Change in Play, Change in Kids

Clearly the way that children spend their time has changed. Here's the issue: A growing number of psychologists believe that these changes in what children do has also changed kids' cognitive and emotional development.It turns out that all that time spent playing make-believe actually helped children develop a critical cognitive skill called executive function. Executive function has a number of different elements, but a central one is the ability to self-regulate. Kids with good self-regulation are able to control their emotions and behavior, resist impulses, and exert self-control and discipline.
....
Sad because self-regulation is incredibly important. Poor executive function is associated with high dropout rates, drug use and crime. In fact, good executive function is a better predictor of success in school than a child's IQ."
And much more.
See also Getting Serious About Play.