It was found that the duration of sleep of the ancient and modern man almost does not vary. Previously, it was assumed, noise and artificial lighting reduce the time to sleep.
Primitive people, devoid of all the joys of civilization, the researchers found, was given to sleep the same time as modern humans. This writes the Current Biology. The average duration of sleep in ancient times was about six hours a day.
To such conclusion scientists have come, having traced the life of the authentic tribes living in the jungles of Tanzania, near Bolivia and Namibia. These people still do gathering and hunting to feed himself and his family. For hunting they use spears and bows, means of technical communication with the rest of society inaccessible to them.
The average duration of sleep in these tribes was 6 hours 25 minutes per day. About the same on sleep isolated people living in Metropolitan areas. Apparently, the parameters for sleep is inherent in the process of evolution. To change will take millions of years.