Where Human Sleep Went Wrong

David Samson observed that the Hadza of Tanzania sleep in fragmented, short, low-efficiency bouts yet report high satisfaction, contradicting the Paleo sleep hypothesis and medical assumptions that uninterrupted sleep is essential. He notes humans sleep the fewest total hours of any primate while allocating a disproportionately large share to REM sleep, a pattern linked to evolutionary shifts such as ground-based sleeping, shelter construction, fire use, and seasonal camp organization.