Children smile 400 times a day on average... adults 15 times. Children laugh 150 times a day... adults 6 times per day. Children play between 4-6 hours a day... adult only 20 minutes a day. What's happened?

Children smile 400 times a day on average... adults 15 times. Children laugh 150 times a day... adults 6 times per day. Children play between 4-6 hours a day... adult only 20 minutes a day. What's happened?