Some people tend to believe that increased pay or rewards can overcome fatigue by increasing the motivation of sleepy crews. Faulty views about the nature of fatigue were once pervasive, and many people still hold them today. There has long been the misconception that fatigue is simply a state of mind rather than something 'real'. The misconception that circadian rhythms can be overcome by sheer willpower is another factor that has produced problems in the workplace. The electric light, night-vision devices, and other technological advancements have been responsible for substantial progress in both the civilian and military worlds. Night-fighting strategies on the battlefield have increased the mobility and lethality of military forces while improving the defensive posture. Private lives that push the limits of human endurance for the sake of work and play at the expense of sleep and rest predispose individuals to poor health, psychological distress, social maladjustment, and risky job performance.