Don’t blame the lure of a glowing smartphone for keeping you up too late. Even people without modern technology don’t sleep the night away, new research says.

Members of three hunter-gatherer societies who lack electricity—and thus evenings filled with Facebook, Candy Crush, and 200 TV channels—get an average of only 6.4 hours of shut-eye a night, scientists have found. That’s no more than many humans who lead a harried industrial lifestyle, and less than the seven to nine hours recommended for most adults by the National Sleep Foundation.

People from these groups—two in Africa, one in South America—tend to nod off long after sundown and wake before dawn, contrary to the romantic vision of life without electric lights and electronic gadgets,