Ch 3: Birth to 2 years

Physical changes

Most physical change in first two years (aside from prental)

During infancy: 1 inch/ month

At 2 (females) or 2.5 (males), toddlers are half as tall as they will be as adults

Two yr olds have much larger heads that adults (nearly full sized brains)

Irregular growth could be indication of health/ nutritional issues, require intervention

Sudden unexpected infant death (SUID)

Occurs when infant under one year of age dies unexpectedly, often while asleep, and there is an identifiable cause of death (eg suffication)

Sudden infant death syndrome (SIDS)

There is no identifiable cause of death

What is recommended to parents as a way to reduce SUIDS risk (mainly suffocation)

ABC method

(Alone, back, crib)

First six months, infants are fed

1. Human milk

2. Infant formula

3. Combination of both

Feeding after 6 months

Infants introduced to solid foods around 6 months (depending on physical development, cultural norms, overall readiness)

Still fed frequently in first year but typically can eat enough is single sitting to eat only three meals

Brain/ nervous system development during first two years

Midbrain and medulla (regulate vital functions) are most fully developed at birth

Least developed part is cortex (perception, body movement, thinking, language)

Synaptogenesis

Creation of synapses, followed by a period of synaptic pruning to make brain more efficient

One year old’s synapsis

Has denser dendrites and synapses than adult does, enabling brain to reorganize neural pathways and connections in response to experience (neuroplasticity)

Network operates far less efficiently than that of the adult

Myelination

Myelin gradually covers individual axons and electrically insulates them from one another, improving the conductivity of the nerve

Biological process of wrapping nerve fibres (axons) in a fatty, protective coating called a myelin sheath to speed up electrical signal transmission

Myelination is most rapid during first two years after birth, continues throughout childhood/ adolescence

What part of the brain isn’t fully myelinated until mid 20s

Reticular formation (regulates formation)

Adaptive reflexes

Such as sucking, helping newborns survive

Some disappear in infancy/ childhood

Others persist throughout life

Eye blink reflex

Shine bright light at eyes/ clap near head

Quickly closed eyelids

Permanent

Protects infant from strong stimulation

Rooting reflex

Stroke cheek near corner of mouth

Head turns towards source

Lost at 3 weeks

Helps infant find the nipple

Sucking reflex

Place finger in infants mouth

Infant sucks rhythmically

Lost at 4 months

Permits feeding

Swimming reflex

Place infant face down in pool of water

Infant paddles and kicks in swimming motion

Lost at 4-6 months

Helps with survival if dropped into water

Moro reflex

Hold infant on back and let head drop slightly or produce a loud sound against supporting surface

Infant makes “embracing” motion by arching back, extending legs, and throwing arms outward then bringing arms in

Lost at 6 months

May have helped infant cling to mother in past

Palmer grasp reflex

Place finger in infants hand and press on palm

Spontaneous grasp of finger

Loss at 3-4 months

Prepares infant for voluntary reaching

Tonic neck

Turn infants head to one side while infant is lying awake on back

Infant takes a “fencing position” one arm extended in front of eyes and the other is flexed

Lost at 4 months

Prepares infant for voluntary reaching

Acquisition of motor skills depends on

Brain development and substantial changes in other body systems

Physical development proceeds from … and from …

Head downward (cephalocaudal pattern)

Centre of body outward (proximodistal pattern)

Motor development

Locomotor skills (gross motion): lifting head, rolling, crawling, walking

Nonlocomotor skills: controlling head movements

Manipulative skills (fine motor)

Wide variability within and between cultural settings

First month motor skills

Locomotion → stepping reflex

Nonlocomotion → lifts head slightly

Manipulative → holds object if placed in hand

Month 2-3 motor skills

Non locomotor→ lifts head 90 degrees when on stomach

Manipulative→ swipe at objects in sight

Month 4-6 motor skills

Locomotor→ rolls over, moves on hands/knees (creeps)

Nonlocomotor→ holds head erect while sat

Manipulative→ reaches for/ grasps objects

Month 7-9 motor skills

Locomotor→ sits without support, crawls

Manipulative→ transfer objects between hands

Preterm infants

Born before 37 weeks

Preterm/ low birth weight may move more slowly through developmental milestones

Catches up by two or three

Visual acuity

How well one can see details at a distance

VA of newborn is 40x worse than normal sighted adult

By 6 months, only 8x worse

Develops rapidly during the first year as a result of synaptogenesis, pruning, myelination

Tracking

Process of following a moving object

Integral to object recognition

Colour vision

Red, green and blue present by 1 month

Infant’s ability to sense colour is almost identical to an adult’s

Depth perception

Ability to perceive whether objets are nearer or farther away than other objects

Not present at birth

When does depth perception develop

Over first months with acquisition of binocular vision

Eleanor Gibson and RD Walk

Studied infant perception using a “visual cliff”

Determine when infants developed depth perception

Development of depth perception involves 3 cues

Binocular cues

Monocular cues

Kinetic cues

Binocular Cues

Involves both eyes; each eye receives a slightly different image of an object

Used to determine distance

Used beginning at 4 months

Monocular Cues

Input from one eye

Interposition: one object is in front of another

Linear perspective: lines get closer together as they get farther away than other

Used last, perhaps at 5-7 months

Kinetic cues

Come from your own motion/ motion of some object

3 month

Auditory acuity

Newborns hear nearly as well as adults do

High pitched noises need to be loud to be heard

Can locate direction of some sounds at birth

Smelling and tasting

Smell has nearly unlimited variations

Newborns react differently to each basic taste

Touch and motion

Best developed of all senses

Responsive to gentle social touching, important in early brain development

Intermodel perception

Ability to integrate info from two or more sensory modalities into a coherent/ holistic experience of a single event or object

Discriminating speech sounds

1 month: discriminate between single syllables (pa vs ba)

6 months: between two syllable words (bada vs baga)

Babies can distinguish sound contrasts in any language but at 6 months this ability begins to fade

Discriminating individual voices

Newborns can discriminate mother’s voice from another female, but not father’s from another male

Mother’s voice is preferred

Babies learn this in utero

Discriminating other sound patterns

Babies recognize melody patterns by 6 months

Piaget and the first two years

Sensorimotor stage (infants use info from senses and motor actions to learn about the world)

Primary, secondary, and tertiary circular reactions: infant progressively gain experience of himself and his surroundings

By 18-24 months infant has the beginnings of mental representation

Assimilation

Info from environment fits with what you already know

Accommodation

Occurs when you change/ accommodate your understanding because it does not fit into an existing schema

Substages of sensorimotor development

Object permanence

2 month olds are surprised when object disappears

6-8 month olds start looking (if partially hidden)

8-12 months reaching for a toy that is completely hidden

Corresponds with infants beginning to show signs of distress when caregivers leave

Piaget’s view of imitation

Infants capable of imitating actions such as hand gestures in first few months

Imitation of facial gestures around 8-12 months

Deferred imitation not possible until 18-24 months

Contemporary research on imitation

Newborns will imitate facial gestures (when observed for one minute or longer)

Infants as young as 6 weeks can defer their imitation for a few mins

Limitations to Piaget’s view

Underestimated cognitive capacities of infants

Perhaps equated lack of physical capacity with lack of cognitive understanding

Babies as young as 4 mo show object permanence

Most 5 mo look to other side of screen when moving object disappears behind it (hold mental representations)

Imitations of facial gestures and defered imitation earlier

Sustained attention

Capacity to hold our attention to stimulus/ task

Improves substantially over first year, and continue into early childhood

At 4 mo we see capacities for controlling attention and shifting focus to begin

Memory

Development requires both development of cognitive skills and language

Results from “mobile task” studies show us that implicit memory is present in infancy

Explicit memory takes more time to develop (why we cant remember much of our earliest years)

Language development in first two years

Language/cognitive development based on Lev Vygotsky’s work (sociocultural theory of development)

Social speech (ec child’s teacher talking through task) supports development of problem solving and decision making capacities

Evident when we hear children engage in ego centric speech (talking to themselves)

Also learn through observation/ social referencing to know how to respond to act in certain situations