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
Sense Newborn Capabilities
Vision Least developed sense accommodation and visual acuity limited sensitive to brightness discriminates some colours tracks moving targets
Hearing Turns to a sound can differentiate loudness, direction, frequency very responsive to speech recognize mothers voice
Taste Prefers sweet discriminates between sour, salty, bitter, sweet
Smell Detects odours turns away from unpleasant ones Breast-fed babies can tell own mothers breast and underarm odor
Touch Responsive to touch, temperature change and pain
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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