I wanted to post a bit more on the video game question. The same applies to any screen-type activity.
This article by Deborah Scott gets to the heart of the issue.
A Confession. For a fleeting moment one morning I thought, “You know, if I just used the internet as a reward, I could get my son to do anything.” Wow, that would be controlling. The idea was canned immediately.
Then came a stark realization that you may discover lurking in your house, too. If I could get my son to do anything I wanted him to do just so long as I gave him internet access, so could anyone else. I was allowing my son to put a ring in his nose. Like a bull, his strong, abundantly useful self could be led anywhere by anyone. I was footing the bill for this ugly situation!
Read the rest of the article here.
I have posted below two articles on how the brain works. An understanding of how the brain works will help you in making your decisions about screen time for your child.