While riding on a train, David notices that the trees and telephone poles close to the tracks seem to flash by, while the buildings, trees, and mountains that are farther away seem to move by more slowly. This phenomenon is called _______________

A) aerial perspective
B) subliminal motion
C) motion parallax
D) motion differential

Answer: C
Rationale: Motion parallax is a monocular depth cue. This cue is used when you or your surroundings are in motion. For example, as you sit in a moving car and look out of the passenger window, you will notice objects closer to you, such as the roadside, parked cars, and nearby buildings appear to move rapidly in the opposite direction of your travel. However, the foothills and mountains in the distance appear to move much more slowly, indicating that they are further away.