An individual is seated in a darkened room. What would you expect their pupils to look like? A light is shone onto their eyes and a change in their pupils is noted, what change would you expect and why?

In dark/dim conditions the human pupil dilates (diameter increases) to allow more light in.In bright conditions the pupil constricts (diameter decreases) and less light enters the eye.This is through a combination of circular muscles in the eye constricting and radial muscles relaxing.