My friend Donna Bethell, physicist and killer cyclist, responds to my previous post:
"My sister Linda, a developmental pediatrician, was telling me recently about some truly hyperactive kids that she sees. These boys are more than just antsy. They are almost literally bouncing off the ceiling - jumping off furniture, oblivious to risk, can't be stopped. She says that at international conferences, physicians from Europe say they never see this problem and think the Americans are exaggerating. We hit on the explanation: the syndrome is highly inheritable and from the 16th to the 19th centuries, just about everyone in Europe who had it immigrated to the New World. What else would induce anyone to get on a leaky old boat, cross a stormy ocean, plow into the wilderness, face savage warriors, and keep going until stopped by another ocean? It's the scientific underpinning of the old adage: the ones with get up and go got up and went.
"The gene pool of Europe has been depleted of the hyperactive, risk-taking, but ultimately constructive and inventive genotypes. The few that didn't immigrate were selectively killed off in two World Wars, the crowning disasters for Europe."
Anybody got any better ideas?