1. Physical Development
In Infancy
Chapter 4
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2. 4 - 2
Patterns of Growth
• Cephalocaudal pattern: Sequence in which
the earliest growth always occurs at the top
• Proximodistal pattern: Sequence in which
growth starts at the center of the body and
moves toward the extremities
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

3. 4 - 3
Height and Weight
• The average American newborn is 20 inches
long and weighs 7 pounds
• Most of the newborns are 18 to 22 inches long
and weigh between 5 and 10 pounds
• Grow about 1 inch per month during the first
year
• By 2 years of age
– Infants weigh approximately 26 to 32 pounds
– Average 32 to 35 inches in height
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

4. 4 - 4
The Brain
• Contains approximately 100 billion neurons at
birth
• Shaken baby syndrome - Brain swelling and
hemorrhaging
• Positron-emission tomography - Scans pose a
radiation risk to babies
• Electroencephalogram - Measure of the
brain’s electrical activity
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

5. 4 - 5
The Brain
• Brain’s development
– Mapping the brain
• Brain has two halves
• Lateralization: Specialization of function in one
hemisphere of the cerebral cortex or the other
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

6. 4 - 6
Figure 4.4 - The Brain’s Four Lobes
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7. 4 - 7
Figure 4.5 - The Neuron
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8. 4 - 8
The Brain
– Changes in neurons
• Myelination
• Connectivity among neurons increases
– Changes in regions of the brain
• Blooming and pruning vary by brain region
• Peak of synaptic overproduction in the visual cortex
followed by a gradual retraction
– Heredity and environment influence the timing and course
• Pace of myelination varies
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

9. 4 - 9
Figure 4.6 - The Development of
Dendritic Spreading
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

10. 4 - 10
Sleep
• Typical new born sleeps approximately 18
hours a day
• Infant sleep-related problem – Night time
waking
• Cultural variations influence infant sleeping
patterns
• REM sleep - Eyes flutter beneath closed lids
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

11. 4 - 11
Sleep
• Shared sleeping
• Sudden infant death syndrome (SIDS): Occurs
when an infant stops breathing, usually at
night
– Suddenly dies without an apparent cause
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

12. 4 - 12
SIDS - Findings
• SIDS is less likely to occur in infants who use a
pacifier when they go to sleep
• Low birth weight infants are 5 to 10 times
more likely to die of SIDS than are their
normal-weight counterparts
• Two recent reviews concluded that breast
feeding is linked to a lower incidence of SIDS
• Infants whose siblings have died of SIDS are
two to four times as likely to die of it
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

13. 4 - 13
Figure 4.10 - Developmental Changes in
Rem and Non-Rem Sleep
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

14. 4 - 14
Nutrition
• Nutritional needs and eating behavior
– Should consume approximately 50 calories per
day for each pound they weigh
– As motor skills improve, infants change:
• From using suck-and-swallow movements
• To chew-and-swallow movements with semisolid and
then complex foods
– Need to have a diet that includes:
• Fruits and vegetables
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

15. 4 - 15
Nutrition
• Breast versus bottle feeding
– Breast feeding is better
• Benefits of breast feeding - Outcomes for the
child
– Gastrointestinal infections
– Lower respiratory tract infections
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

16. 4 - 16
Nutrition
• Benefits of breast feeding - Outcomes for the
mother
– Breast cancer
– Ovarian cancer
– Type 2 diabetes
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

17. 4 - 17
• Mother should not breast feed:
– When infected with HIV or some other infectious
disease
– If she has active tuberculosis
– If she is taking any drug
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.
Nutrition

18. 4 - 18
Reflexes
• Built-in reactions to stimuli
– Govern the newborn’s movements – Automatic
• Rooting reflex: Occurs when the infant’s
cheek is stroked or the side of the mouth is
touched
– Turns his or her head in an effort to find
something to suck
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

19. 4 - 19
Reflexes
• Sucking reflex: Occurs when newborns
automatically suck an object placed in their
mouth
– Enables newborns to get nourishment before they
have associated a nipple with food
– Serves as a self-soothing mechanism
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

20. 4 - 20
Reflexes
• Moro reflex: A neonatal startle response that
occurs in reaction to a sudden, intense noise
or movement
– It is believed to be a way of grabbing for support
while falling
• Grasping reflex: Occurs when something
touches the infant’s palms
– Responds by grasping tightly
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

21. 4 - 21
Gross Motor Skills
• Involve large-muscle activities, such as walking
• Development of posture
– Posture - Dynamic process linked with sensory
information in the skin, joints, and muscles, which
tell us where we are in space
• Learning to walk
• The first year - Motor development
milestones and variations
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

22. 4 - 22
Figure 4.15 - Milestones in Gross
Motor Development
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

23. 4 - 23
Gross Motor Skills
• Development in the second year
– Toddlers become more skilled and mobile
– By 13-18 months
• Toddlers can pull a toy or climb stairs
– By 18-24 months
• Toddlers can walk quickly
• Balance on their feet
• Walk backward and stand and kick a ball
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

24. 4 - 24
Fine Motor Skills
• Involve more finely tuned movements, such as
finger dexterity
• Two types of grasps:
– Palmer grasp
– Pincer grip
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

25. 4 - 25
What are Sensation and Perception?
• Sensation: Occurs when information interacts
with sensory receptors
– Eyes, ears, tongue, nostrils, and skin
• Perception: Interpretation of what is sensed
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

26. 4 - 26
Visual Perception
• Visual acuity and human faces
• Color vision
• Perceptual constancy
– Size constancy: Recognition that an object
remains the same
• The retinal image of the object changes as you move
toward or away from the object
– Shape constancy: Recognition that an object’s
shape remains the same
• Its orientation changes
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27. 4 - 27
Visual Perception
Habituation
• Decreased
responsiveness to a
stimulus after repeated
presentations of the
stimulus
Dishabituation
• Recovery of a habituated
response after a change in
stimulation
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

28. 4 - 28
Figure 4.20 - Visual Acuity During the
First Months of Life
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

29. 4 - 29
Figure 4.22 - Examining Infants’ Depth
Perception on the Visual Cliff
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document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.

30. 4 - 30
Other Senses
• Hearing
– Changes in hearing
• Loudness
• Pitch
• Localization
• Touch and pain
• Smell
• Taste
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31. 4 - 31
Intermodal Perception
• Involves integrating information from two or
more sensory modalities
– Vision and hearing
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