Development

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Development Learning

• Kimberley Clow
• Office Hours Mon 10am-12pm
• kclow2_at_uwo.ca
• http//instruct.uwo.ca/psychology/215a-570

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Outline

• Development
• Development of the Visual System
• Methodologies
• Different Perceptual Developments
• Beyond Vision
• Experience
• Deprivational Effects
• Critical Periods
• Restored Vision

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Visual System Develops
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Retinal Development
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Acuity
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Contrast Sensitivity
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Developmental Differences
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Colour
1 Week
2 Months
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Other Eye Developments

• Eye Movements
• Saccades
• Smooth Pursuit
• Accommodation
• Near-Sighted

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Infants are born with astigmatism
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Methodologies

• Unlearned Responses
• eye movements (fixation and scanning)
• reflex responses (startle, avoidance)
• preferential looking
• Learned Responses
• habituation
• Infant Psychophysics
• Forced-choice preferential looking
• Topic Specific

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Fixation Scanning
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Age Differences
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Face Perception
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Reflex Responses
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Preferential Looking
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What Do They Prefer?
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When Paired
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Habituation
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Forced-Choice Preferential Looking
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Form Perception
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Perception of Motion
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Depth Perception
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(No Transcript)
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Monocular Depth Cues
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Stereoscopic Depth Perception
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Overview
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Not Just Vision
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Experience
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The Oblique Effect
Poorer Acuity
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Anomalous Early Experience

• Naturally occurring conditions that can interfere
  with normal vision
• Cataracts
• Strabismus
• Astigmatism
• Major Consequences are
• Amblyopia
• Stereoblindness

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Strabismus
Esotropia Exotropia
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Consequences
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Astigmatism
Goggle Rearing
Cylinder Rearing
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Results
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Monocular Deprivation
Experience with just one eye
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Results
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Normal Vision
Deprived Vision
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Binocular Deprivation
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Whats Going On?

• Normal cells compete for synaptic contact
• End up getting equal shares
• When a deprivation occurs (naturally,
  temporarily, or otherwise), there is no
  competition
• Loses its share of cortical space

Cortical neuron
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Critical Periods

• When these deprivations occur is important
• Early in life
• Can be reversed if corrected soon enough
• Examples
• Cataracts must be corrected within 5 months
• Astigmatisms must be corrected within 2 years
• Stereopsis requires retinal disparity from 3 ½-6
  months

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Perceptual-Motor Development
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Adapting to Displaced Vision
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Restored Vision

• Molyneux asked whether a man born blind who had
  his sight restored later in life would recognise
  by sight an object that he had previously only
  known by touch
• Nativists say yes Empiricists say no
• Several studies have examined this question
• What does research say

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The Case of SB
Elephant
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3 months
Immediate
6 months