Final answer:
The visual cliff is a laboratory device used to test depth perception in infants. It helps researchers understand if infants can perceive depth and whether they can perceive the visual cliff as a drop-off.
Step-by-step explanation:
The visual cliff is a laboratory device for testing depth perception in infants. It consists of a platform with a Plexiglas surface that creates the illusion of a drop-off. By placing an infant on the platform and observing their behavior, researchers can determine if the infant can perceive depth and whether they are able to perceive the visual cliff as a drop-off.