Chapter 4 - Physical Development in Infancy and Toddlerhood CD

What are the two components of Overall Physical Growth?

Weight and Height

What is the weight of an infant at birth?

7½ pounds

What percentage of body weight does an infant lose in the first few days after birth?

5-7%

At 5 months, how does an infant’s weight develop?

Doubled weight

At 1 year, how does an infant’s weight develop?

Tripled weight (about 15 lbs.)

At 2 years, how does an infant’s weight develop?

Quadrupled (about 30 lbs.)

What is the height of an infant at birth?

20 inches

How does an infant’s height develop in the first year?

Grows 1 inches per month (about 32 inches)

How does an infant’s height develop in the second year?

Slows down (about 36 inches)

What are the Trends of Growth/Maturation?

Cephalocaudal Pattern and Proximodistal Pattern

What is the Cephalocaudal Pattern?

• “From head to foot”

• Size, weight, and sophistication/motor skills

• Gain control in upper body first

What motor skills are developed in the Cephalocaudal Pattern?

Gross Motor Skills

What are Gross Motor Skills?

• Large muscle movements

  • e.g., Walking

    • Uniquely human

    • Extremely difficult to mimic in robots

    • Implications for other areas of development

      • Development of the physical domain leads to cognitive and socioemotional domain development

        • Mobility → problem solving and feelings

What does it take (Constraints) to Walk?

Structural, Patterning of Movement, and Coordinating Information from Other Senses

What is the Structural Constraints for Walking?

• For upright posture

• Disproportioned

  • Infants = 25% head

• Rigid bones needed

What is the Patterning of Movement Constraints for Walking?

• Coordination of joints

• Weight shifting

• Motor control (brain)

What is the Coordinating Information from Other Senses Constraints for Walking?

• Vision

  • Optic flow → closer to an object, looks closer, moves to avoid it

• Vestibular System

  • Movement, balance, and orientation

    • E.g., moving room studies

At what age (months) can an infant prone, lift its head?

0 to 1 month

At what age (months) can an infant prone, chest up, use arms for support?

2 to 4 months

At what age (months) can an infant roll over?

2 to 5 months

At what age (months) can an infant support some weight with legs?

3 to 6 months

At what age (months) can an infant sit without support?

4.5 to 8 months

At what age (months) can an infant stand with support?

5 to 10 months

At what age (months) can an infant pull self to stand?

6 to 10 months

At what age (months) can an infant walk using furniture for support?

7 to 13 months

At what age (months) can an infant stand alone easily?

10 to 14 months

At what age (months) can an infant walk alone easily?

11 to 14 months

What is the Proximodistal Pattern?

• Develop from center to extremities → gain control of central larger muscle groups, then later develop control of smaller muscle groups for fine motor skills

• From gross motor to fine dexterity

What motor skills are developed in the Proximodistal Pattern?

Fine Motor Skills

What are Fine Motor Skills

• Small muscle groups

• E.g., Reaching and Grasping

What are the three reflexes of Fine Motor Skills?

Prereaching, Ulnar Grasp, and Pincer Grasp

What is Prereaching?

• Involuntary reaching

• Primitive

• First few weeks

What is the Ulnar Grasp?

• Fingers close against palm

• Reaching reflex weakened & turns into control

• 3 months of age

What is the Pincer Grasp?

Thumb & index finger can close

The Cephalocaudal Pattern

• The greatest growth always occurs at the top of the head with physical growth in size, weight, and feature differentiation gradually working from top to bottom.

• Sensory and motor development proceed according to the cephalocaudal pattern

The Proximodistal Pattern

• Growth starts in the center of the body and moves toward the extremities

• An example is the early maturation of muscular control of the trunk and arms, as compared with that of the hands and fingers.

What is a Neuron?

Nerve cell that stores & processes info

How heavy is the newborn brain?

Newborn brain is 30% its adult weight

How many neurons are present at birth?

• 100 to 200 billion neurons

• Overproduced = insurance policy to make sure there is enough

What is Programmed Cell Death?

• Redundant or not being used = die off

• Not fully connected - experience dependent

• At 2 years old - brains is 70% of adult weight

• Growth due to increase in size of neurons, glial cells. dendrites, & myelination

What is the Prenatal Period?

Neural tube forms - 3 weeks past conception

What are the 4 Developmental Events

1. Cell Production

2. Cell Migration

3. Cell Elaboration

4. Myelination

What is Cell Production?

• Between 10-26 weeks most produced

• 250,000 new nerve cells per minute

What is Cell Migration

The directed movement of single cells or groups of cells in response to chemical and mechanical signals

When is Cell Migration complete?

7 months

What is Cell Migration interfered with by?

• Alcohol

  • Overshoot destination, cells become scrambled, FAS)

• Radiation

  • Undershoot alignment of cells during the migration process

What components are in Cell Elaboration?

Dendritic Spreading, Synaptic Pruning, and Brain Plasticity

What is Dendritic Spreading?

Dendrites (receivers) & Axons (senders) overconnect

What is Synaptic Pruning?

Weeding, connections NOT cells die off

What is Brain Plasticity?

• Flexibility of function

• Elasticity is greatest the younger you are

What is Myelination?

• Fatty covering of axons

• Prenatal through infancy

• Need fat in diet

  • Best source of fat is breastmilk

What Is the Cerebral Cortex?

• ¼ inch outer covering (Grey Matter) of the brain

• 85% of brain’s weight (Densley packed neurons)

• Activation patterns indicate how the brain is developing

What is the Prefrontal Cortex in terms of the Development of the Cerebral Cortex?

• Highest forms of thinking → logic and reasoning

• Last part of the brain to fully develop

What is Plasticity in terms of the Development of the Cerebral Cortex?

• Flexibility in changing

• Lessens with age

  • As you get older, less likely to recover from trauma, or learn new things

    • E.g., trauma

    • E.g., learning second language

What is the sensitive Periods of Brain Development?

Heightened sensitivity to environment. Nurture is important

What are the Sensitive Periods of Brain Development?

Deprived Early Environments and Appropriate Stimulation

What are Deprived Early Environments?

E.g., Romanian Orphans

What were the Romanian Orphans?

Not stimulated in touch, love, or played with. Grew up in a bad environment, which led them to gain severe socioemotional, cognitive, and deprived brain. Led to areas of under activity in the brain → not properly connected → severe impairments

What is Appropriate Stimulation?

Bucharest Early Invention Project

What is the Bucharest Early Invention Project?

• Foster Care vs. Institutionalization

• Placed before 2 years old = kids did well

• Placed at or after 2 years old = kids did not do well

• Foster care → better neurological, cognitive, social, and emotional skills

• Less than 2 years of age is ideal

What 2 concepts determine Brain Growth?

Experience-Expectant Brain Growth and Experience-Dependent Brain Growth

What is Experience-Expectant Brain Growth?

• Normal stimulation needed to express genes

• Foundation for a brain requires experience/normal stimulation

• Makes us the same

  • Emotions, Romanian Orphans had no empathy, couldn’t connect with others

What is Experience-Dependent Brain Growth?

• Specialized stimulation from unique experiences

  • Brain trauma, raised by musicians, etc.

• Makes us different

  • Emotionally, intellectually, atheleticness

How does Nutrition Effect Development?

• Infants need to eat proportionally more than adult or child does

• Need more energy for growth

  • 50 calories per day per pound → 2x the amount of calories for an adult

What is Breastmilk coined as?

Nature’s perfect food

About how many women breastfeed?

50%

Why do some women not breastfeed?

Issues of working/getting time off

What percentage of Fat is in Breastmilk?

55%

What percentage of Carbohydrates is in Breastmilk?

38%

What percentage of Protein is in Breastmilk?

7%

What makes Breastmilk high in calories?

The fat, carbohydrates, and protein

Who Benefits from Breastfeeding?

Infants, Mothers, and Society

What are the Infant Benefits of Breastfeeding?

• Appropriate weight gain

• Fewer allegries & infections

• Lower incidence of cancers

• Lower chance of SIDS

• Higher levels of neurological & cognitive development

What are the Maternal Benefits of Breastfeeding?

• Delays Fertility

• Less reproductive cancers (Breast, Uterine, Ovarian, and Endometrial)

• Decreased levels of osteoporosis → brittle bones as becoming older

• Promotes postpartum weight loss → burns calories

• Enhances emotional health → less chance of PPD

What are the Societal Benefits of Breastfeeding?

• Optimum child spacing

• Improved vaccine effectiveness because the babies are healthier

• Financial savings to government and families → Cheaper health insurance because people are relatively healthier

When is Solid Food introduced to a child?

4-6 months

What type of solid food should be introduced first?

Start with cereals (bland, rice cereals) → then introduce protein, vegetables, and fruit

What is Weaning?

Process of changing from breast to bottle because they’re confused

What is Nipple Confusion?

Child rejects the bottle because they are unfamiliar with it

What are the differences between Infants and Adults?

• Infant’s nutritional needs are different than an adult’s

• No cow’s milk before 1 yr of age → need to develop enzymes

• Need of fat in diet through 1st 2 years

  • Brain development = Myelination (fait in diet)

What are the Psychosocial Effects of Nutrition?

Healthy/attractive infant is viewed as more likable & intelligent

What are the Learning Capacities?

Classical Conditioning and Operant Conditioning

What is Learning?

Change by experience

What is Classical Conditioning?

• Learning by association

• Physiologically based

  • Associate → physiological response

    • Rat → raised heart rate

• Newborns demonstrate classical conditioning

• Little Albert

What is Operant Conditioning?

• Learn by consequences

  • Reinforcers → strengthen behavior

    • Reward by presenting an object

  • Punishers → weaken behavior

    • Take away an object

• Skinner box

What is Habituation?

• Gradual reduction in strength of a response due to repeated exposure

• Based off of novelty & curiosity

• Measures attention, memory, & knowledge

What are the Preferences of Habituation?

Novelty Preference and Familiarity Preference

What is the Novelty Preference?

• More time spent on a new object

• Recent memory/short term memory

• Spend 80% of the time on the new face, while spending 20% of the time on the old face

What is the Familiarity Preference?

• More time spent on the old object

• Remote memory/long term memory

• Looks longer at old face because they are familiar to it

What predicts later intelligence?

• Novelty and Familiarity Preference

  • How efficient a child is using their attention to learn things, reflected in an IQ test years later

  • Measure of quick & flexible thinking

What is Imitation (of facial exposures)?

• Controversial

• Reflexive in newborns???

  • Present, then disappears

• Can get a child to consistently imitate facial expression at 6 months of age because of developed vision

What is happening in Imitation (of facial exposures)?

Mirror Neurons

What are Mirror Neurons?

• Motor neurons that imitate

• Foundation for social and emotional development

• 6 months or sooner

  • Hand movements

    • Even though baby is not moving, their brains act as if they were moving

What is an Infant Preference?

Face Perception

What are Infant Preferences?

• Contrast Sensitivity (black & white patterns)

• Color vision in place at 4 months

What is Face Perception?

• Lots of contrast

• Social and emotional information (eyes)

• Adaptive

What is happening during Face Perception?

Fusiform Face Area, and Prosopagnosia

What is the Fusiform Face Area?

Specialized brain area for false perception

What is Prosopagnosia?

Can’t recognize familiar faces

What is Perceptual Narrowing?

• General ability becomes specialized

• Tested with Habituation