Week 5: Perceptual development

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Week 5 Perceptual development

• Visit website!
• Midterm in two weeks!

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Perceptual Development

• 3 Methods of determining infant perception
• Visual Preference
• Developed by Fantz
• Infant in chamber with peephole, what do they
  look at most?

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Perceptual Development

• 4 Methods of determining infant perception
• Visual Preference
• Evoked potentials

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Perceptual Development

• 4 Methods of determining infant perception
• Visual Preference
• Evoked potentials
• High Amplitude sucking
• Habituation/dishabituation

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Senses of the Newborn
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Senses continued

• Infants legally blind at birth
• 20/600 at birth, by 12 months, down to 20/100
• Auditory perception good
• Esp speech perception
• Have likes and dislikes re. Food
• Have sweet tooth like many of us
• Show aversion to unpleasant smells
• Wrinkle their noses at bad smells
• Babies like to be touched
• Massaged preemies grow faster

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Pattern Perception (0-2 months)

• Prefer moderately complex stimuli over highly
  complex stimuli
• Like a lot of contrast, like black on white

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Examples Which will babies prefer?
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Examples Which will babies prefer?
This one, due to high contrast!
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Pattern Perception (0-2 months)

• Prefer moderately complex stimuli over highly
  complex stimuli
• Like a lot of contrast, like black on white
• Show externality effect

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Externality Effect
Seen at 1 month!
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Externality Effect now Obsolete!
Gone at 2 months
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Pattern Perception (0-2 months)

• Prefer moderately complex stimuli over highly
  complex stimuli
• Like a lot of contrast, like black on white
• Show externality effect
• Like curvy things, contours

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Which will babies prefer?
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Which will babies prefer?
This one!! Its curvilinear
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Pattern Perception (0-2 months)

• Prefer moderately complex stimuli over highly
  complex stimuli
• Like a lot of contrast, like black on white
• Show externality effect
• Like curvy things, contours
• Vertical symmetry

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Which will babies prefer?
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Which will babies prefer?
This one! Its symmetrical!
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Later Form Perception 2 4 months

• Are scanning whole objects
• Start to show a preference for the human face ?

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Face perception

• Babies seem to like to look at faces Why?
• Contrast
• Curvy
• Symmetrical

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Take all features into account
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Face perception

• Babies seem to like to look at faces Why?
• Contrast
• Curvy
• Symmetrical
• Will track a face-like picture over something
  else

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Guess which baby prefers?
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Guess which baby prefers?
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Face perception

• Early on, spend more time looking at edges and
  contours than at middle of face
• By 3 months clearly prefer normal faces, and that
  of own mother, and that of attractive people
• By 7 months, can categorize and remember faces
• By 8-10 months, can interpret emotion in faces

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Meaning of face preference

• Could be simply a result of stimulus preferences
• Could be social
• Dannemiller Stevens, 1988
• Data from eye gaze studies
• We as adults have a face processing area

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Intermodal Perception

• Enrichment vs differentiation theory
• Senses separate must integrate vs. senses
  integrated must differentiate
• Former is probably correct
• Bahricks research

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Integrating modalities

• Babies need to achieve three tasks
• Attending
• At 5-7 months, sight and sound well integrated
• Identifying
• Can integrate two sense to identify source or
  objects
• Locating
• They can integrate visual and grabbing
  information to time a grasp properly

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Infants spatial abilities

• Chapter 8

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Babies 3D vision

• Have binocular vision, or stereopsis, by 3 months
• Can only use 2D pictorial cues at 7 months
• Show evidence of perceiving depth by 1 month, but
  do not interpret it until they are actively
  crawling

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Visual Cliff

• Gibson and Walks animal study
• Crawling infants wont cross to mom!
• If placed on visual cliff at 2 months, heart rate
  DEceleration, i.e. interest
• Richards Rader (1981)

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Interaction

• Babies who move understand principles of movement
  better
• Will search for objects that have changed
  location whether due to objects movement, or to
  own movement
• Bai Bertenthal (1992)

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Other spatial/ pictorial cues

• Have depth perception
• Show size constancy to some extent, esp with
  motion between 1 and 3 months, but not fully
  until 6 months
• Cant use linear perspective until 7 months
• See subjective contours at 3 months

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Subjective Contours
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Other spatial/ pictorial cues

• Have depth perception
• Show size constancy to some extent, esp with
  motion between 1 and 3 months, but not fully
  until 6 months
• See subjective contours at 3 months
• Appear to have mature understanding of objects

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Spelkes Rod and Frame test
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Spelkes Rod and Frame Test, cond
Babies know that it is not 2 separate rods, but
rather one whole!
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Childrens Knowledge of Objects

• Baillargeons work Babies seem to have knowledge
  about objects at a very young age
• Uses Violation-of-Expectation paradigm to infer
  4 month old infants knowledge about occluders

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Violation of Expectation Habituation Event
Screen moves through 180 degree plane until baby
gets bored
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Violation of Expectation Test Event 1 Possible
Event
Screen moves through 112 degree plane and stops
at occluder
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Violation of Expectation Test Event 2
Impossible event
Screen moves through 180 degree plane despite
occluder
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Violation of Expection Results

• Babies are surprised by the impossible event
• Find the same thing with other object properties
  like containment and support
• Spelkes research with the moving rod is the same
  idea

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What does it mean?

• Babies may be born with principles of cohesion,
  continuity and contact
• Maybe not innate knowledge about objects per se,
  but innate constraints
• Possess tools to build cognition from birth
  object concept present early on!

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Later Form Perception 6 months to 1 year

• By 7 months get linear perspective
• By 9 months can extract whole from a random dot
  pattern
• By 12 months, they watch a single point of light
  trace an object, then act like theyve seen the
  whole object

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Summary

• Infants are born with fairly strong capabilities
• Infant perception develops rapidly over the first
  year of life
• By 12 months, they can see well and are moving,
  and are largely able understand their
  environment!

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How old is this woman?
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What do you see here?
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Ambiguous Figures

• Physiological perception is done early cognitive
  perception develops later
• They cant shift back and forth between pictures
  until they are 10-11 years old!

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Later Perceptual development, cond

• Children also have trouble telling some letters
  apart
• M W
• b d h

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Spatial orientation

• Children before 3 have a hard time keeping track
  of their environment
• Tend to view things in a straight line
• Poor cognitive mapping

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Spatial Cognition

• Herman, Shiraki, Miller, 1985
• Examined 12 younger (3 4) and 12 older (4.5
  5.5) nursery school children who had been at the
  same school for the same amount of time
• Brought them to 3 locations and asked them to
  point out 5 landmarks
• Older a bit better than younger, but still not
  great
• Very young children have difficulty inferring
  spatial relationships, even in familiar
  environments

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More Spatial Problems

• Field Dependence / Independence
• Have trouble with this until they are 10
• Embedded Figures Task

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Embedded Figure 1
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Embedded Figure 2
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More Spatial Problems

• Field Dependence / Independence
• Have trouble with this until they are 10
• Embedded Figures Task
• Role of Inhibition and Cognitive Flexibility,
  hard to separate figure and ground

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Summary of Perception and Spatial Cognition

• In infancy, focus is on what infants can or
  cannot see, i.e. colours, patterns, depth, etc
• How much is present at birth? How much develops?
• Once they see, they improve in how flexibly they
  see items
• They also improve in how they mentally represent
  the space around them