Optical
Illusions
This page illustrates that our visual perception cannot
always be trusted. The components of an object can distort the
perception of the complete object.
Our mind is the final arbiter of truth.
Optical illusions have been studied for millenia. The ancient
Greeks used a technique known as entasis which incorporates
a slight convexity in the columns of the Parthenon to compensate
for the illusion of concavity created by parallel lines. Many
of the following illusions have been popularized by psychologists
and artists like Hering, Ehrenstein, Meyer, Zöllner, Müller-Lyer,
Poggendorf, and Escher.
1.
Moiré Patterns Moiré patterns are formed when two grids or line
drawings are superimposed. The intersections of the lines create
new patterns not present in the originals. This figure contains
two drawings consisting of lines radiating from a point. One
drawing is fixed and the other moves thus generating a changing
interference pattern of circles that cross both points. The
animation can be stopped or re-started by pressing SHIFT and
clicking on the pattern. You can also click-and-drag to control
the motion of the pattern manually.
2.
Word Color Test
In this test DO NOT READ the words, say aloud the COLOR of each
word.
YELLOW
BLUE ORANGE
BLACK RED
GREEN
PURPLE YELLOW
RED
ORANGE GREEN
BLACK
BLUE RED
PURPLE
GREEN BLUE
ORANGE
This is
a type of psycholinguistic test that poses some difficulty because
the portion of the brain that handles language has the conflicting
tasks of verbalizing the color of the written words while ignoring
the meaning of words representing colors.
3.
Three Streams. Apparent movement of the streams is created by
afterimages as our eyes shift to examine the picture.
