According to laughter research, you're not as funny as you think.
Did you ever make up a joke? Most likely you have not. Learn more on this Moment of Science.
Laughter research has found that less than 20% of laughter is a sincere response to someone's humor. In fact, it's primarily a social signal.
The back of your eye, called the retina, has two kinds of cells: rods and cones. In bright light the cones are what we use, while in dim light the cones are less active and the rods take over.