We love our sleep here at Education Quizzes. What time do you go to bed? Are you an early-rising lark or a late night-loving owl? Well, new research published this week in the Proceedings of the Royal Society of London B, suggests that it’s our ancestors’ fault that we all have different sleep patterns.
Sleep is a difficult thing to study. Most research done into the subject requires a special ‘sleep lab’ which is not a natural place to lie down and relax! This new study is unique in that it observed people’s time spent sleeping during their everyday (and night!) lives.
Anthropologists went to Tanzania in Africa to study the Hadza people. They have a hunter-gatherer lifestyle almost unchanged for tens of thousands of years, so very similar to that of our ancestors. A group of 20 people were given devices to monitor when they were awake or asleep, and observed for 20 days.
What the scientists discovered was that, for 99.999% of the time there was at least one person awake. The whole group was asleep at once for just 18 minutes over the whole 20 day period. That suggests that there is probably a good reason why we don’t all sleep at the same time.
Our circadian rhythms determine when we are tired or lively and these are controlled, mostly, by our DNA – some of us wake early and go to bed early (larks) whilst others sleep in and stay up late (owls). Whilst this may be unsuited to our modern lifestyles, it must have given us an evolutionary advantage. But what?
Our ancestors, as well as being hunters, were also hunted. A group of us all sleeping would have been easy pickings for a sabre-toothed tiger. But if there is always someone awake then the group has a pair of eyes and ears to warn them of approaching danger. Rather than us choosing to set a guard, it seems that evolution pre-programmed us so we didn’t have to, and it’s a habit we just haven’t managed to kick.
Teenagers and young adults seem to stay up the latest, and the aged wake up earlier -just as the youngsters are going to bed! So, next time mum tells you to go to sleep at 3 in the morning, tell her it’ not your fault – the ancestors made you do it!