MULLER LYER
ILLUSION: EXPLAINED
Dr. Shalini Mittal
Depth Perception
◦ One explanation of the Muller-Lyer illusion is that our brains perceive the depths of the
two shafts based upon depth cues. When the fins are pointing in toward the shaft of
the line, we perceive it as sloping away much like the corner of a building.
◦ When the fins are pointing outward away from the line, it looks more like the corner of a
room sloping toward the viewer. This depth cue leads us to believe that this line is closer
and therefore longer.
Confusion Theory
Size Constancy explanation
◦ According to psychologist Richard Gregory, this illusion occurs because of a
misapplication of size constancy scaling. In most cases, size constancy allows us to
perceive ob
◦ In the three-dimensional world, this principle allows us to perceive a tall person as tall
whether they are standing next to us or off in the distance. When we apply this same
principle to two-dimensional objects, Gregory suggests, errors can result.jects in a
stable way by taking distance into account