Marle, not to correct you but pupils are SUPPOSED to be small in sunlight and large in darkness, like the lens of a camera,--to control the amount of light that gets in. The only time this isn't true (when the subject isn't on drugs) is when the person is very frightened.
You can observe this is animals of prey too: when a cat is on the hunt their pupils get big to let in more light so they can detect the prey's movement more easily.