For many years, scientists have known that sleep deprivation reduces the ability to maintain attention. When asked to monitor a computer screen and press a button whenever a red dot appears – a pretty simple task – participants who are sleep deprived are much more likely to have lapses in attention. They don’t notice a bright red dot and fail to respond within a half-second. These lapses in attention are due to a buildup in pressure to sleep and are more common at points in the 24-hour circadian cycle when the body expects to be sleeping.