What the graph reveals is that exceptional minds generally have entirely un-exceptional sleep schedules. As you can see, most were in bed around 10:00pm and up not too long after dawn. And most were getting a solid seven or eight hours of sleep. There are studies that suggest that people are more creative at night or when they're tired, but clearly, even the world's greatest minds couldn't run on empty. Other than Balzac (who made up for his night-owlish ways during the evening and morning), very few geniuses were pulling all-nighters (although, we can't speak for their college years).