Download Sensory and Perceptual Development

Sensory and Perceptual
Development
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Sensation: Detection of stimuli
by sensory means and
transmission of this information to
the brain.
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Perception: Interpretation of
sensory input
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All senses present at birth
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only have evidence that infants
show preferences (and aversions)
for taste and smell (and sometimes
hearing).
 these are the two most “dominant
senses” at birth.
3 senses
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Taste
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Infant can distinguish between
sweet, sour, salty, and bitter
Smell
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Can distinguish at birth (show
preference or aversion)
After only 6 days they show a
preference for mothers smell
(learned response)
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Touch
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Apparent at birth but the stimulus
needs to be stronger than older
infants
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Sensitive to extremes: pressure, pain,
temp.
4th and 5th
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Vision (at birth)
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Focal length: 8-10 inches
Very fuzzy image (20/600)
Newborns show a preference
for high contrast and patterns
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Initially look around the edge of
image to develop a unified
whole
Can only discriminate red and
green (not blue).
Vision
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Limitations
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At birth eye is only ~70% of adult size
Lens (of the eye)- Accommodation is not
functioning properly. It is not changing
shape as it should.
3 sets of muscles that move the eye
Immature neural system
Photoreceptors (rods and cones) are not as
densely packed at birth
Development of Depth Perception
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Tested using the “Visual Cliff”. Most 6 month
old infants will not crawl to their mothers
over the “cliff”
Visual Cliff video
Audition/Hearing
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Audition/hearing
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Begins developing in the fetus
Newborns prefer (and recognize)
mothers voice
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@26 weeks fetus begins to hear
(auditory system developed)
fetus hears moms voice (through the
body)
It develops hair cells in the inner ear
which are in the range of mom’s voicepreferential maturation of hair cells in
the chochlea
Audition/Hearing
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Sounds are muffled
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Caused by excess fluid in the ears
and the Eustachian tube
In adults these tubes are slanted
downward and drain
These are horizontal in newborns
and don’t drain easily, this is why
newborns get earaches often.
Limitations
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Eustachian tube- smaller (narrower) and
horizontal
Preferential development to hear sound
in female (particularly mothers) voice
range