Electricity is dramatically different from torches/candles. It's brighter and safer, so it got used more. It affected how we sleep: http://aeon.co/magazine/psy

Electricity is dramatically different from torches/candles. It's brighter and safer, so it got used more. It affected how we sleep: http://aeon.co/magazine/psychology/why-broken-sleep-is-a-golden-time-for-creativity/ http://aeon.co/magazine/psychology/why-broken-sleep-is-a-gol... > Prior to Edison, says the Virginia Tech historian A Roger Ekirch, author of At Day’s Close: Night in Times Past (2005), sleep had been divided into two distinct segments, separated by a period of night-waking that lasted between one and several hours. The pattern was called segmented sleep. > Sleep patterns of the past might surprise us today. While we might think that our circadian rhythm should wake us only as the sun rises, many animals and insects do not sleep in one uninterrupted block but in chunks of several hours at a time or in two distinct segments. Ekirch believes that humans, left to sleep naturally, would not sleep in a consolidated block either.