Sleep is also an interesting example of pathologies in American high schools. Why do they start so insanely early though every teacher knows that first period is a waste of time and every parent knows what happens to teenagers' circadian rhythms? The answers always seem to come down to the incentives: high school isn't actually about learning but is more about daycare and sports and the convenience of organized groups like teachers or parents, and when push comes to shove, the latter win.