Transcript Voyages in Development, Second Edition, Spencer A. Rathus

Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
Chapter 5
Infancy: Physical Development
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
What are the Sequences of Physical Development?
• Cephalocaudal Development
– Upper part of the head to the lower parts of the body
• Proximodistal Development
– Trunk outward – from body’s central axis toward periphery
• Differentiation
– Tendency of behavior to become more specific and distinct
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
What Patterns of Growth Occur in Infancy?
• Weight doubles at about 5 months; triples by first birthday
• Height increase by 50% in first year
• Infants grow 4 to 6 inches in second year; and gain 4 to 7 pounds
• Growth appears continuous but actually occurs in spurts
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
Figure 5.2 Changes in the Proportions of the Body
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
What is Failure to Thrive?
• Growth impairment during infancy and early childhood
• Causes may be organic or non-organic
– Biologically based or non-biologically based
• Links to physical, cognitive, behavioral and emotional problems
• Deficiencies in caregiver-child interaction may play a role
• Canalization – catch up growth once FTT is resolved
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
What are the Nutritional Needs of Children?
• Infants require breast milk or iron fortified formula
• Solid foods may be introduced about 4 to 6 months
– Iron-enriched cereal, strained fruits, vegetables and meats
• Whole cow’s milk delayed until 9 to 12 months
– Teething biscuits in later part of first year
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
Guidelines for Infant Nutrition
• Build up variety of foods
• Avoid overfeeding or underfeeding
• Don’t restrict fat and cholesterol
• Don’t overdo high-fiber foods
• Avoid items with added sugar and salt
• Encourage high-iron foods
U.S. Dept of Agriculture, 2000
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
Why do Women Bottle-feed or Breastfeed their Children?
• Choice to breastfeed is influenced by
– Attitudes regarding benefits for bonding and infant health
– Fear of pain, unease with breastfeeding and public breastfeeding
– Domestic and occupational arrangements
– Community and familial support
– Level of education
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
What are the Advantages and Disadvantages
of Breast Milk?
• Advantages of breast milk
– Conforms to digestion process
– Possesses needed nutrients
– Contains mother’s antibodies
– Helps protect against infant diarrhea
– Is less likely, than formula, to cause allergies
• Disadvantages of breast milk
– HIV, alcohol, drugs and environmental hazards may be transmitted
through breast milk
– Physical demands on mother
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
Development of the Brain and
Nervous System
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
What are Neurons?
• Basic unit of nervous system, receive and transmit messages
• Neurons vary according to function and location, but all contain
– Cell Body
– Dendrites
– Axon
• Neurotransmitters
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
Figure 5.3 Anatomy of a Neuron
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
How do Neurons Develop?
• As child matures
– Axons grow in length
– Dendrites and axon terminals proliferate
– Connection networks become more complex
• Myelin Sheaths
– Makes messages more efficient
– Myelination occurs with maturation
– Inhibition of myelination results in disease
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
What is the Brain?
• Command center of organism
– Brain of neonate weighs less than one pound
– By first birthday, the brain triples in weight, reaching nearly 70% of
adult weight
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
Structures of the Brain
• Medulla
– Controls basic body functions - heartbeat, respiration
• Cerebellum
– Maintains balance, control motor behavior, coordinate eye
movements with body sensations
• Cerebrum
– Allows human learning, thought, memory and language
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
Figure 5.5 Structures of the Brain
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
How Does the Brain Develop?
• Growth Spurts in Brain Development
– Prenatal – fourth and fifth months
• Proliferation of neurons
– Prenatal – 25th week through 2 years old
• Proliferation of dendrites and axon terminals
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
Figure 5.6 Increase in Neural Connections in the Brain
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
How do Nature and Nurture Affect the Development
of the Brain?
• Brain development is affected by maturation (nature) and
sensory stimulation and motor activity (nurture)
– Rats in enriched environment
• More dendrites and axon terminals
– Human infants have more neural connections than adults
• If activated by experience, connection survives
• If not activated, connection does not survive
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
Motor Development
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
What is Motor Development?
• Developments in the activity of muscles, and is connected with
changes in posture, movement, and coordination
• Follows cephalocaudal and proximodistal patterns
– Lifting and holding head before torso
– Voluntary reaching
– Locomotion
• Sequence: rolling over, sitting up, crawling, creeping, walking, running
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
What are the Roles of Nature and Nurture
in Motor Development?
• Maturation (nature)
– Myelination and differentiation is needed for certain voluntary motor
activities
• Experience (nurture)
– Experimentation to achieve milestones
– Slight effect in training to accelerate motor skills
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
Sensory and Perceptual
Development
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
Development of Visual Acuity and Peripheral Vision
• Neonates are nearsighted
– Greatest gains in visual acuity between birth and 6 months
– By about 3 to 5 years of age, approximate adult levels
• Neonates have poor peripheral vision
– Perceive stimuli within 30 degree angle
– By 7 weeks increases to 45 degrees
– By 6 months of age, equal to adult
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
What Captures the Attention of Infants?
How do Visual Preferences Develop?
• Neonates attend longer to stripes than blobs
– By 8 to 12 weeks, prefer curved lines over straight
• Infants prefer faces
– Discriminate maternal and stranger faces
– Prefer attractive faces
– Pay most attention to edges
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
Figure 5.11 Preferences in Visual Stimuli in 2-Month-Olds
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
Figure 5.12 Eye Movements of 1- and 2-Month Olds
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
How do Researchers Determine Whether Infants will
“Go Off the Deep End”?
• Depth Perception
– Develops around 6 months (onset of crawling)
• Research using the Visual Cliff
– Gibson and Walk (1960)
– Relationship between crawling and fear of heights
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
Figure 5.13 The Visual Cliff
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
A Closer Look
Strategies for Studying the
Development of Shape Constancy
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
What are Perceptual Constancies?
How do they Develop?
• Perceptual constancy – perception of object remains stable
although sensations may differ under various conditions
• Size constancy – perception of object’s size remains stable
although retinal size may differ
– Appears by 2 1/2 to 3 months
• Shape constancy – perception of object‘s shape remains stable
although shape on retina may change
– Appears by 4 to 5 months
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
How Does the Sense of Hearing Develop in Infancy?
• Neonates can orient toward direction of a sound
– 18 months locate sounds as well as adults
• By 3 1/2 months discriminate caregivers’ voices
• Infants perceive most speech sounds present in world languages
– By 10 to 12 months, lose capacity to discriminate sounds not found
in native language
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
Figure 5.14 Declining Ability to Discriminate the Sounds of Foreign Languages
Childhood and Adolescence: Voyages in Development, Second Edition, Spencer A. Rathus
Chapter 5
What is the Evidence for the Roles of Nature and Nurture
in Perceptual Development?
• Sensory changes are linked to maturation of nervous system
(Nature)
• Experience also plays a role (Nurture)
– Critical periods
• Newborn kittens with patched eye – become blind in that eye
• Nature and nurture interact to shape perceptual development.