Being a "Glass half full" kind of person, might help you sleep better at night.
Researchers from the University of Illinois studied the sleeping Habits of more than 35-hundred people.
They were also asked to fill out a survey in order to measure their level of optimism.
Those who were more optimistic were more likely to get between six and nine hours of sleep a night.
They were also less sleepy during the day and had fewer symptoms of insomnia, than those with a negative attitude.
The scientists believe that positivity may reduce the effects of stress, allowing optimists to sleep peacefully.