Which of the following represents perceptual constancy?
1) We recognize the taste of McDonald's food each time we eat it.
2) In the photos with people, the people almost always are perceived as figure and everything else as ground.
3) We know that the brightness of a printed page has not changed as it moves from sunlight to shadow.
4) From the time they are very young, most people can recognize the smell of a dentist's office.
5) The cold water in a lake doesn't seem so cold after you have been swimming in it for a few minutes.