PERCEPTION

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Chapter 5

• PERCEPTION

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Sensations vs. Perceptions

• Perception
• Our interpretations of the real world
• How do Sensations Become Perceptions
• A perception begins with some stimulus which
  activates sense receptors
• Once activated, a sense organ transforms energy
  into electrical signals or impulses that travel
  to the brain

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Sensations vs. Perceptions (continued)

• Parts of the Brain transform electrical signals
  into basic sensations
• Sensations are your first experiences of outside
  stimuli
• They consist of meaningless bits of sensory
  information
• Each of us has a unique set of experiences that
  may automatically add meanings, feelings, or
  memories to our perceptions

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Sensations vs. Perceptions (continued)

• The brain automatically assembles many thousands
  of individual sensations into a meaningful
  pattern or image which is called perception
• Personalized interpretations rather than true
  copies of things in the real world

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Enduring Issues in Perception

• Role of Learning
• Newborns senses are all functional and some
  degree of perceptual ability is probably innate

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Enduring Issues in Perception (cont)

• Parts vs. the Whole
• Feature Analysis
• The theory that we perceive a form on the basis
  of a relatively small collection of features,
  which can be combined, rotated and expanded
  (Structuralism)

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Enduring Issues in Perception (cont)

• Gestalt School
• Psychologists who believe that a meaningful
  overall pattern (Gestalt) is perceived before its
  parts are recognized
• The whole is more than the sum of its parts

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Enduring Issues in Perception (cont)

• Perceptual Illusions
• Used to determine how people process perceptual
  information
• Bottom-Up vs. Top-Down Processing
• Bottom-Up sensory receptors to brain
• Top-Down perceivers expectations context play
  a role from the beginning
• Perceptual Sets
• learned expectations that are based on our
  personal social or cultural experiences. These
  expectations change or bias what we see.

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Functions of Perception

• Where is it? Location
• Attention
• Automatic distinguishing object from background
• Deliberate allocation of attention
• Depth Perception
• Ability to experience depth in visual perception
  (relative absolute distances)

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Functions of Perception Depth Perception
(continued)

• Binocular Depth Cues depend upon the movement
  of both eyes
• Convergence based on signals sent from the
  muscles that turn the eyes
• Binocular (Retinal) Disparity depends on the
  distance between the eyes
• Stereopsis
• 3-D Glasses

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Functions of Perception Depth Perception
(continued)

• Monocular Depth Cues
• Depend upon the signals sent from one eye
• Determined by how objects are arranged in the
  environment

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Functions of Perception Depth Perception
(continued)

• Motion Parallax
• Relative Size
• Constancy
• Linear Perspective
• Texture Gradient
• Aerial Perspective
• Occlusion (Interposition)

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Functions of Perception (continued)

• Illusions of Depth
• Muller-Lyer, Ponzo, Ames Room, Vista Paradox (pg.
  146)
• If our perceptual cues are changed, our otherwise
  reliable perceptual processes can be deceived

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Functions of Perception (continued)

• Auditory Localization
• Differences in how and when a sound reaches the
  two ears enable the brain to compute the location
  of its source

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Functions of Perception (continued)

• Is it Moving? Movement
• Motion Perception
• We distinguish between changes in environment
  that are caused by movements in the environment
  and changes that are caused by our own movements

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Functions of Perception (continued)

• Illusions of Motion
• Apparent Motion (Phi Phenomenon)
• Induced Motion (moon appears to move through
  clouds)
• Motion Aftereffect (train stops and objects
  outside appear to move backwards)

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Functions of Perception (continued)

• What is It? Form
• Feature Analysis
• Involves the recognition of features (lines,
  intersections corners) as well as location,
  orientation, contrast, and fuzziness.
• Features are grouped into clusters

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Functions of Perception (continued)

• Gestalt View (Principles)
• Figure-Ground Distinction
• In organizing stimuli, we tend to automatically
  distinguish between a figure and a ground
• The figure with more detail, stands out against
  the background, which has less detail

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Functions of Perception (continued)

• Gestalt View (continued)
• Grouping
• Similarity
• Proximity
• Continuity
• Simplicity
• Closure

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Subliminal Perception

• Subliminal Messages
• Brief auditory or visual messages that are
  presented below the absolute threshold, which
  means that there is a lt50 chance that they will
  be perceived
• Although subliminal messages may be ineffective
  in changing behavior, there is evidence that
  emotions may unknowingly or subliminally
  influence perception

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Cultural Diversity Changing Perceptions

• Besides affecting social and personal values,
  cultural influences can also affect our
  perception of color depth, constancy, and motion

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ESP Extrasensory Perception

• A group of psychic experiences that involve
  perceiving or sending information outside normal
  sensory processes or channels
• Includes 4 general abilities
• Telepathy
• Precognition
• Clairvoyance
• Psychokinesis

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ESP Extrasensory Perception (cont)

• Most academic psychologists do not yet accept the
  existence of psychic powers or extrasensory
  perception, which are collectively called psi
  phenomena
• Trickery
• Questionable methodology (unreliable scientific
  procedures)

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Application Creating Perceptions

• Creating Reality
• Virtual Reality
• A perceptual experience of being inside an
  object, moving through an environment, or
  carrying out some action that is entirely
  simulated by a computer

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Application Creating Perceptions (continued)

• Creating Impressions
• Social psychologists have concluded that facial
  features have a significant affect on our first
  impressions of people
• First impressions are also influenced by racial
  stereotypes, both positive and negative, based on
  physical features such as skin and hair color

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Life-Span Changes in Perception

• Sensory World of Infant
• A newborns distance senses (sight hearing) are
  not as developed as the sense of touch, smell
  taste
• Sight is probably the least developed sense
• They have poor depth perception and are unable to
  see the full color spectrum
• By the age of 7 months, babies vision hearing
  are acute

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Life-Span Changes in Perception

• The Aging Senses
• Sensory systems begin aging during the 40s and
  may become severe by the 70s and 80s
• Life in a noisy environment may contribute to
  hearing loss
• Medication may reduce taste sensitivity