Perceptual Organization

Module 13

Overview

Perceptual Organization Form Perception

Depth Perception

Perceptual Constancy

PerceptionAoccudrnig to rscheearch at Cmabrigde Uinervtisy, it deosn’t mttaer in what oredr the ltteers in a wrod are, the olny iprmoetnt tihng is that the frist and lsat ltteer be at the rghit pclae. The rset can be a toatl mses and you can still raed it wouthit porbelm. This is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.

Perceptual Organization

How do we form meaningful perceptions from sensory information?

We organize it.

Perceptual Organization: Gestalt

Gestalt--an organized whole tendency to integrate pieces of information

into meaningful wholes a school of psychology founded in Germany

in the 1900s that maintained our sensations are processed according to consistent perceptual rules that result in meaningful whole perceptions, or gestalts.

Feature Pop Out

• The slanted line amongst vertical lines Pops Out, but the cross amongst horizontal and vertical lines does not pop out.

(a) (b)

Organization of the visual field into objects (figures) that stand out from their

surroundings (ground).

Figure GroundT

ime S

avings Suggestion, ©

2003 Roger S

heperd.

Laws of Perceptual Organization

Figure-Ground

Animated necker cubehttp://dogfeathers.com/java/necker.html

From MIND SIGHTS by Shepard © 1990 by Roger N. Shepard. Used with permission by W. H. Freeman and Company. Return

Figure 5.7: Reversible Images

Faces or Vases?

Grouping

After distinguishing the figure from the ground, our perception needs to organize the figure into

a meaningful form using grouping rules.

Grouping demo

• http://9gag.com/gag/aOqOYv6?ref=9g.m

Perceptual Organization: Gestalt

Grouping Principles proximity--group nearby figures together similarity--group figures that are similar continuity--perceive continuous patterns closure--fill in gaps connectedness--spots, lines, and areas are

seen as unit when connected

Laws of Perceptual Organization

Law of Continuity

Law of Proximity

Laws of Perceptual Organization

Law of Closure

Law of Similarity

Law of Proximity

The Law of Similarity

The Law of Continuity

Perceptual Organization: Closure

Gestalt grouping principles are at work here.

Reversible Dancer?

• Note which direction the dancer is rotating. Clockwise or counter?

http://www.news.com.au/heraldsun/story/0,21985,22556281-661,00.html

Grouping & RealityAlthough grouping principles usually help us

construct reality, they may occasionally lead us astray.

Both photos by W

alter Wick. R

eprinted from G

AM

ES

Magazine. .©

1983 PCS G

ames L

imited Partnership

Depth Perception

Visual Cliff

Depth perception enables us to judge distances. Gibson and Walk (1960) suggested that human infants (crawling age) have depth perception. Even newborn animals show depth perception.

Inne

rvis

ions

Figure 13.7 Relative sizeMyers: Exploring Psychology, Seventh Edition In ModulesCopyright © 2008 by Worth Publishers

Binocular Cues

Retinal disparity: Images from the two eyes differ.

Binocular Cues

Convergence: Neuromuscular cues. When two eyes move inward (towards the nose) to see near objects and outward (away from the nose) to see

faraway objects.

Monocular Cues

Relative Size: If two objects are similar in size, we perceive the one that casts a

smaller retinal image to be farther away.

Perceptual Organization: Depth Perception -- Relative Size

Monocular Cues

Interposition: Objects that occlude (block) other objects tend to be perceived as

closer.R

ene Magritte, The B

lank Signature, oil on canvas, N

ational Gallery of A

rt, Washington. C

ollection of M

r. and Mrs. Paul M

ellon. Photo by Richard C

arafelli.

Interposition

Monocular Cues

Relative Height: We perceive objects that are higher in our field of vision to be farther away than those that are

lower.

Image courtesy of S

haun P. V

ecera, Ph. D

., adapted from

stimuli that appered in V

ecrera et al., 2002

Tall Arch

Rick F

ried

ma

n/ B

lack S

tar

Monocular Cues

Relative motion: Objects closer to a fixation point move faster and in opposing direction to those objects that are farther away from a fixation

point, moving slower and in the same direction.

Motion Perception

Motion Perception: Objects traveling towards us grow in size and those moving away shrink in size. The same is true when the observer moves to or

from an object.

Apparent Motion

Phi Phenomenon: When lights flash at a certain speed they tend to present illusions of motion. Neon signs use this principle to create motion

perception.

Two lights flashing one after the other.One light jumping from one point to another: Illusion of motion.

Monocular CuesLinear Perspective: Parallel lines, such as railroad tracks, appear to converge in the distance. The more the lines converge, the

greater their perceived distance.

© T

he New

Yorker C

ollection, 2002, Jack Ziegler

from cartoonbank.com

. All rights reserved.

Perceptual Organization: Linear Perspective

Linear Perspective

Monocular Cues

Light and Shadow: Nearby objects reflect more light into our eyes than more distant objects. Given two identical objects, the dimmer one appears to

be farther away.

From

“Perceiving S

hape From

Shading” by V

ilayaur S

. Ram

achandran. © 1988 by S

cientific Am

erican, Inc. A

ll rights reserved.

In or Out?

Monocular Cues

Texture Gradient: Indistinct (fine) texture signals an increasing distance.

Perceptual Constancy

Perceiving objects as unchanging even as illumination and retinal

images change.

Figure 13.10 Shape constancyMyers: Exploring Psychology, Seventh Edition In ModulesCopyright © 2008 by Worth Publishers

Figure 13.9 Perceiving shapeMyers: Exploring Psychology, Seventh Edition In ModulesCopyright © 2008 by Worth Publishers

Link

Perceiving familiar objects as having consistent color even when changing illumination filters

the light reflected by the object.

Color Constancy

Color ConstancyLink

Moon Illusion

The moon just above the horizon typically appears to be unusually large because we perceive it as unusually far away from ourselves.

This illustrates the importance of context effects.

Size-Distance Relationship

The distant monster (below, left) and the top red bar (below, right) appear bigger

because of distance cues.

From Shepard, 1990

Alan C

hoisnet/ The Im

age Bank

Ponzo Illusion• Converging lines indicate that top line is

farther away than bottom line

From Perplexing Puzzles and Tantalizing Teasers, (p.75), by Martin Gardner, 1988, New York Dover.

Figure 5.2: Misperceiving Reality: Which Line Is Longer?

Size-Distance RelationshipBoth girls in the room are of similar height.

However, we perceive them to be of different heights as they stand in the two corners of the

room.

Both photos from S. Schwartzenberg/ The Exploratorium

Ames Room

The Ames room is designed to demonstrate the size-distance illusion. Ramachandran

explains the Ames room http://www.youtube.com/watch?v=Ttd0YjXF0no

Lightness Constancy

The color and brightness of square A and B are the same.Cou

rtesy

Edw

ard

Ade

lson

Visual Illusions

The Ponzo Illusion

The Müller - Lyer Illusion

EXPLORING PSYCHOLOGY(7th Edition in Modules)

David MyersPowerPoint Slides

Aneeq AhmadHenderson State

University

Worth Publishers, © 2008