in high school my friend always insisted that you can test better when you're tired. she never slept. and she managed to do pretty well. in high school i barely studied, and there was no way i needed eight hours to study that i would stay up all night.
but now I'm really tired. and kind of sleep deprived. and I'm going to take a test in a half hour. so I'll find out if my friend's theory is true, or if it only worked for her.