A PSY 203 Lecture Notes - Lecture 3: Nystagmus, Visual Cortex, Evoked Potential
13 Jun 2018
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Day 3: How do we First Come to relate to the World?
While the development of visual sensation is based on genetics, the development of visual
perception is influenced by environmental factors
True because visual perception is influenced by environmental factors because on how you see things and
the way you focus on certain things and others may focus on other things
How do we First Come to relate to the World?
VISION
• Low level processing (brightness) happens in the retina
• Mid level processing. (color) happens in midbrain structures
• High level processing (identifying faces) happens in the visual cortex
Low level processing
• By 2 days, infants can detect differences in brightness
• By 4 months, infants can compare brightness levels
o But brightness perception is still not adult like
How would we know what a baby sees?
• Visual activity: the sharpness of vision
o Blurry vs. clear
• Preferential looking method
• Present 2 stimuli and see which one the baby prefers to look at
How would we know what a baby sees?
• Same image over and over until baby habituates
• Show a new image and see if the baby dishabituates
• Measure looking time
Optokinetic nystagmus method
• Measures the jumping of the eye when watching a series of objects moving
• Drag a panel of stripes and measure eye jumping
• When stripes are too close, the eyes stop jumping from stripe to stripe.
Visually evoked potential method
• Measuring brain response to visual stimulus
• Rapid alternation between gray background and stripes
• When stripes are easy to see, the brain will differentiate stripes from gray; otherwise it won’t.
What drives this development?
• Babies are born with astigmatism
• The eye gets bigger until image is in focus
• Eye growth is determining by visual input
Color
• Do infants perceive color on a continuum or in categories?
• How would u test this?
o Infants perceive and categorize color
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