Final answer:
The monocular depth cue responsible for making cheekbones look higher or more prominent when blush is applied is called shading. It utilizes variations in light and color to mimic depth on a two-dimensional surface.
Step-by-step explanation:
The monocular depth cue of shading explains why blush makes cheekbones look higher or more prominent. Shading allows our visual system to perceive contours and variations in depth using only one eye. It is one of the many monocular cues we use to perceive depth in a two-dimensional visual field.
Others include linear perspective, interposition, relative size, and height in the visual field.
Shading helps in creating the illusion of a three-dimensional object on a two-dimensional surface by varying the tones and colors to mimic how light would naturally interact with the object, thus enhancing certain features to appear more raised or lowered than they really are.