Meanwhile, the military is going straight to the brain in search of wakefulness: It is researching a process called transcranial direct current stimulation (tDCS), which more or less zaps the brain with electricity, in the hope that it will keep soldiers constantly at the ready. Andy McKinley, an in-house researcher for the U.S. Air Force, helped publish a study on the phenomenon. “When we kept people up for 30 hours, we found that tDCS improved their vigilance performance twice as much as caffeine, and the effect lasted twice as long. Caffeine lasted two hours, tDCS lasted about six.” For the sleep-unhappy public, unregulated and unapproved tDCS-applying devices have already found their way onto civilian markets.