Human sleep patterns were once controlled by circadian rhythms governed by day and night. But now, according to a new study, almost everyone in the United States has a sleep pattern that's controlled by when they watch TV. A massive survey on time management conducted by the U.S. Department of Labor Statistics shows that most people watch TV between 11 - 11:15, dropping off to sleep when they switch the tube off. The hour when nighttime falls affects this pattern very little. Human sleep patterns are therefore more malleable than believed, and it's possible people could change them as easily as changing channels.
According to the authors of the study, which comes out this week in the Journal of Labor Economics:
While natural daylight patterns have some effect on people's life patterns, the demands of global business—market openings, etc—and regular television schedule demarcate the boundaries of most Americans' lives . . . Individuals in early television zones (Central and Mountain) are 6.4 percentage points less likely to be watching television between 11 and 11:15 p.m. than those in later zones, but if the sunset is pushed back by an hour the probability of watching TV at 11pm only increases by about one percentage point. The implications for people who want to change their sleep patterns — to get up earlier, say, or go to bed at a regular time — are enormous. If you are somebody who watches TV, you can simply turn the TV off earlier and give your body a cue that it's time to sleep.
If you are in the "professional service" sector (finance, information, business services), you are more likely to follow the time zone cue, while you are in other services sector (education, health, leisure, and hospitality), you are probably more responsive to television cues.
I love it when science actually backs up common sense. Though the idea that our circadian rhythms have been replaced by late-night TV rhythms is sort of creepy.