I CAN
• Use Gestalt Psychology to explain optical
illusions.
Perceptual Ambiguity and
Distortion
Ambiguous figures
Images that are
capable of more than
one interpretation
Illusions
The incorrect
interpretation of a stimulus
pattern
(shared by others in the same
perceptual environment)
Copyright © Allyn and Bacon 2006
Perceptual Illusions
Do you see
or
?
Copyright © Allyn and Bacon 2006
The Gestalt Laws of Perceptual
Grouping
• Max Wertheimer (1923)
These laws suggest how our
brains prefer to group
stimulus elements
together to form a percept
Closure
Similarity
Proximity
Continuity
Common fate
Prägnanz
Closure
Tendency to fill in
gaps in figures and
see incomplete
figures as complete
• Similarity
We tend to group similar
objects
• Proximity
We tend to group objects
together when they are
near each other.
• Continuity
– We prefer perceptions of
connected and continuous figures
over disconnected and disjointed
ones
• Common Fate
– We tend to group similar objects
together that share a common motion
or destination
• Prägnanz
• We perceive the simplest
pattern possible
• This is what makes things
such is
as reduced
proofreading
text
Reality
to aits
simplest
so difficult
form
Law of Pragnanz and the ‘face’
on Mars
• People mentally
process visual
information
that…
– is symmetrical
– contains the
simplest shapes
possible
– contains the
fewest number
of shapes
CAN I?
• Use Gestalt Psychology to explain optical
illusions.
Necker Cube
14
• There are only white circles at the
intersections
Who is this
a picture of?
If you said Clinton you
are correct. If you said
Clinton and Gore, you
Are wrong. Its a picture
of Bill Clinton in the foreground and the
same picture of him in the background, but
with a different haircut.
The rows of black and white squares are
all parallel.
The vertical zigzag patterns disrupt our
horizontal perception.
The center circles are both the
same size.
• Warped Squares?
There are no curved lines in these figures. You
can use a ruler to check it out.
The diagonal patterns created by the tiny
squares distort the perception of the pictures.
Various Illusions
Expanding spiral
http://www.michaelbach.de/ot/mot_adapt/index.html
Moving color dots
http://www.michaelbach.de/ot/mot_silencing/index.html
Motion Induced Blindness
http://www.michaelbach.de/ot/mot_mib/index.html
Kaleidoscope Motion
http://www.michaelbach.de/ot/mot_kaleidoscope/index.html
Can you find "the hidden tiger"? Not the
obvious one that everyone sees. Look for
words in stripes
Can you see both the frog
and the horse on this
visual illusion?
You probably see Albert
Einstein on this picture.
However, if you stand up and
step 15 feet away, you will see
Marilyn Monroe on the same
picture.
Old and Young - Crazy Optical Illusion Painting
Can you find the man’s face in the coffee beans?
1000
20
30
1000
1030
1000
+ 20
______
4100
Dogs in the yard– black & white/color
http://www.illusions.org/dp/color.htm
Beach scene – color/black and white
http://www.grandillusions.com/opticalillusions/colour_illusion/
High Society, or a Donkey?