One thing that's fairly obvious to me is that people (and children especially) are spending less and less time outdoors. If you want some research, here's a study that shows how people are moving away from outdoor recreation.
I see lots of explanations for why this is happening: It's not safe to allow children to play outside. Kids are busy with homework and structured activity. Neighborhoods aren't designed for walking and playing.
While these things may be true, they are relatively minor reasons for the decline. I think the cause is much simpler - in a word, electronics. This includes tv, video games, the internet, and other associated devices. All this even has a fancy name now, "videophilia", which is the "new human tendency to focus on sedentary activities involving electronic media."
What interesting to me is how this trend parallels the obesity crisis. Simple carbs are something the body is not capable of handling. They are superstimuli, similar to drugs and alcohol. They provide a temporary high that, over time, can lead to addiction.
Videophilia seems to work along the same lines. People get sucked into electronic media not because it's benefiting them, but because it provides a high level of stimulation. In comparison, nature can seem "boring".
I can attest to the seductiveness of videophilia. A few times at work I've had to turn off my computer in order to get my real work accomplished. Electronic distractions are too easily accesible nowadays.
Unfortunately, I don't see much to stop this trend. There is nothing that is built in by evolution that will lead people to make better choices about these things. Only the slow road of analysis, education and persistence will lead to change.
