Mark and a Jacob are driving home on a college break. Mark is in the passenger seat. Bored, Mark gazes into the middle of an empty field. He notices that distant hilltops seem to move slowly in the same direction in which their car is moving; by contrast, mile markers on the side of the highway seem to whiz past them in the opposite direction. The difference in the apparent speed and direction of objects' motion serves as a depth cue termed motion:.

Parallax

Explanation: Parallax is usually an error which should be avoided when taking measurements. It is the observed difference in the apparent position of an object when viewed from different positions. Motion parallax is the change in the position of an object due to the viewer's movement. In motion parallax, the object distance to the observer's eye seems to affect the relative motion of the object. That is objects close by or near the observer's eye such as mile markers seems to rush or whiz past relative to the observer's direction while distant objects such as hills and mountain tops moves relatively slowly in the opposite direction.

either wyoming or idaho