Chapter 6: Perception

Perception

•  The organization and interpretation of our sensations. It is how we create meaning for what we see, touch, hear, feel and smell.

Perception

•  Selective Attention: the idea that we are only aware of a small percentage of what we experience.

Selective Attention

•  The most famous example to illustrate selective attention is known as the “cocktail party effect.”

Red Green Blue

Yellow Orange

Red Yellow Black

Blue Red

Orange Green Blue

Green Yellow

Blue Yellow

Orange Yellow

Red Black Green Red

The Stroop Effect

The Stroop Effect

Selec%ve  A)en%on  Theory:  the  interference  occurs  because  naming  colors  requires  more  a)en%on  than  reading  words.    

Selective Attention

• Change Blindness* •  Inattentional Blindness*

Perception •  Visual Capture: refers

to the tendency for vision to dominate the other senses.

Does this picture help you remember the example from your book?

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Perceptual Organization •  Gestalt: an organized

whole. •  Gestalt psychologists

emphasize humans’ tendencies to integrate pieces of information into meaningful wholes.

•  Things are not seen as sum

of parts but immediately as wholes.

Gestalt Principle: Mind Always Wants to Make Stimuli Meaningful.

•  The fact that you can read this sentence… “it deosn't mttaer in waht oredr the ltteers in a

wrod are, the olny iprometnt tihng is taht the frist and lsat ltteer be at the rghit pclae”

…illustrates gestalt principles are at work to make

things a meaningful whole.

Gestalt Principle: Mind Always Wants to Make Stimuli Meaningful.

Gestalt Psychology l Grouping:    the  perceptual  tendency  to  organize  s%muli  into  coherent  groups  

 l Gestault/Grouping  Principles:      

l Proximity  l Similarity  l Con%nuity  l Closure  l Connectedness  

Proximity: tendency to group nearby figures together

• 

Similarity: tendency to group figures that are similar

• 

Continuity: tendency to perceive continuous patterns

• 

Closure: tendency to fill in the gaps in visual information.

Connectedness: spots, lines and areas are seen as a unit when connected

• 

Perceptual Organization

•  Figure-Ground Relationship: tendency to organize information into objects (figure) that stand out from their background(ground)

Figure Ground Illusion

Depth Perception •  Depth Perception:

the ability to see objects in three dimensions. Allows us to gauge distance.

•  Visual Cliff: illustrated

that crawling infants and newborns perceive depth.

Types of Depth Perception •  Binocular Cues: depth cues that rely on the

use of two eyes. •  Examples of Binocular Cues:

– Retinal Disparity: idea that images of an object from the two eyes differ. The closer the object, the larger the difference (disparity.)

– Convergence: extent to which the eyes converge inward when looking at an object that brain keeps track of to measure distance.

Retinal Disparity and the Sausage Illusion

Types of Depth Perception l Monocular  Cues:    distance  cues  that  are  available  to  either  eye  alone.    ODen  used  in  art.  

l Examples  of  Monocular  Cues  l Rela:ve  size:    smaller  image  is  more  distant  l Interposi:on:  closer  object  blocks  distant  object  l Rela:ve  Clarity:  hazy  object  seen  as  more  distant  l Texture:    coarse=close;  fine=distant            

James J. GIBSON

l Among  the  first  to  discover  the  importance  of  texture  gradient  for  perceiving  depth.    Most  surfaces  have  a  texture  but  it  becomes  less  detailed  as  the  surface  recedes  into  the  background.  

 

key name

Types of Depth Perception l Examples  of  Monocular  Cues  Con:nued:  

l Rela:ve  Height:  higher  objects  seen  as  more    distant  l Rela:ve  Mo:on:  closer  objects  seem  to  move    faster  l Linear  Perspec:ve:    parallel  lines  converge  with  

 distance  l Rela:ve  Brightness:    closer  objects  appear    brighter  l Light  and  Shadow:    nearby  objects  reflect  more    light  to  our  eyes.      

Monocular Cue?

Monocular Cue?

Who is closer: Snoopy or Woodstock?

Woodstock

How do you know? Woodstock blocks part of Snoopy. In other words, INTERPOSITION.

Monocular Cue? • 

Mor

e de

tail

Less

det

ail

Closer

Further away

Monocular Cue?

Highlights  and  shadows  can  provide  informa%on  about  an  object's  dimensions  and  depth.    

Because  our  visual  system  assumes  the  light  comes  from  above,  a  totally  different  percep%on  is  obtained  if  the  image  is  viewed  upside  

down.      

Monocular Cue?

Real Quick: Phi Phenomenon

•  Motion Perception: Illusion of Movement with Blinking Lights

What  concept  is  illustrated  in  this  video?  

(h)p://www.youtube.com/watch?v=OIGaDXH9v2o&feature=player_embedded)  

Perceptual Constancy

l Perceptual  Constancy:    perceiving  objects  as  unchanging  despite  changes  in  re%nal  image  

l shape    l size  

Interplay Between Perceived Size and Distance

•  Using monocular cues for distance can often cause us to perceive incorrect information.

Muller-Lyer Illusion Involves Misperception of Line Segments

Muller-Lyer Illusion is Culturally Specific to Western Architecture

Poggendorf's Optical Illusion*

The single line if

continued joins with the _______ line.

Impossible Object

Sensory Deprivation and Perception

Ki)ens  raised  without  exposure  to  horizontal  lines  later  had  difficulty  perceiving  horizontal  bars.    Remember  that  sensory  depriva%on  affects  infants  worse  than  older  animals  and  humans.    

 

Perceptual Adaptation l Perceptual  Adapta:on    

l (vision)  ability  to  adjust  to  an  ar%ficially  displaced  visual  field  

 l prism  glasses  

Perceptual Set – the power of expectancy

l Perceptual  Set    

A  situa:on  where  a  person  is  predisposed  (more  likely)  to  perceive  one  thing  over  another.  

Bill Clinton and ?

Power of Expectancy/Set

Perceptual Set

Usually See Saxophone Player Now Instead of…

Woman

Perceptual Set*

Provide  punctua%on  that  will  make  the  words  below  meaningful:    TIME  FLIES  I  CANT  THEYRE  TOO  FAST    

Is there Extrasensory Perception?

•  Extrasensory Perception: claim that perception can occur apart from sensory input. – Telepathy – Clairvoyance – Precognition

•  Parapsychology: study of paranormal phenomenon, including ESP and psychokinesis.