You show a child two tall and thin glasses filled with equal amounts of water. you pour the water from one glass into a short, wide glass and tell the child to take the glass with the most water in it. you are observing the child's capacity to
it's phycology, the study of the human's response to stimuli, which you are trying to find out whether or not the child can tell that they both have the same amount. hope this helps:)
