Chapter 4: physical and cognitive development in the first two years Flashcards
Average size of newborn
Appearance of newborn
- Average neonate is: 51cm long and 3.4kg
- At birth may have red skin and be covered in vernix (i.e., oily protection against infection) and lanugo (i.e., fuzzy prenatal hair)
- Head may be elongated due to pressure of birth canal
- Fontanelles or gaps in the bones of the head – “soft spots”
APGAR scale
Apgar scale: consists of ratings to calculate the baby’s heart rate, breathing effort, muscle tone, skin colour and reflex irritability.
- 0-2 score is given to each characteristics and the test is taken after they emerge and at five minutes.
- The test is taken twice as some babies find it difficult to adjust to their environment.
- A rating of 7 or above indicates the baby is in a healthy condition.
Central nervous system
Size of brain at birth and then at 2 years
Myelin
- Brain and nerve cells of spinal cord
- Coordination and control of perception and motor responses
- At birth, brain is c. 25% of adult weight
- By 2yrs, grown to 75% of adult weight
- Growth of neurons and connecting fibres
- Connections become myelinated (the coating of neural fibres with an insulating fatty sheath called myelin, which speeds the efficiency of message transfe)
Sleep patterns of infants
• Newborns sleep an average 16hrs per day
- Patterns change over time
- By 6mths average of 13 – 14hrs per day
- By 24mths average of 11 – 12hrs per day
• Adults average of 6 – 8hrs per day
SIDS
Risks
- Sudden and unexplained death of apparently healthy infant
- Leading cause of death in infants who survive first few weeks after delivery
- Most prolific between 2 – 4mths
- Unsure of cause– could be a combination of factors including underlying biological defect; gene mutations of heart; defects in brain stem regulating breathing, heartbeat, body temperature, and arousal
- Risks include sleeping on stomach, sleeping on soft surfaces, passive smoking, mother smoking when pregnant, baby being too hot or too cold
Acuity
keenness or fineness of discrimination
Visual Acuity
• At birth, infants have vision but lack acuity
- Objects often blurry, even at 6m
- Better at tracking moving objects
- Improves steadily during infancy
• Some evidence that infants respond preferentially to face-like patterns
Auditory Acuity
- Ability to hear is present at birth for most infants
- Moro reflex - startle response to loud sound
- Infants prefer complex sounds (noise and
voice)
• At a few days old can differentiate between:
- 2 and 3 syllables
- Emotional tones in language
- Ascending and descending tone
Early Human Reflexes
- tonic neck reflex (fencing)
- rooting
- babinski (toe flare)
- moro (noise)
- grasping/ darwinian
Motor skills
Gross
Fine
voluntary movements of the body or parts of the body
- Gross (i.e., movement of large muscles of arms, legs, and torso)
- Fine (i.e., movement of small muscles such as fingers, toes)
2 trends of motor skills
Cephalocaudal
Proximodistal
- Cephalocaudal (head to tail)
- Head larger and more developed compared to body
- Use upper parts of body before lower parts
- Proximodistal (near to far)
- Centre of body outwards
- E.g., head and trunk before arms and legs, hands and feet, then lastly fingers and toes
Motor development screening
-
Brazelton Neonatal Behavioural Assessment Scale (NBAS)
- Motor organisation; reflexes; state changes; attention and interactive capacity; CNS stability
- Up to 2mths
-
Bayley Scales of Infant Development
- Measures motor skills (fine and gross) and mental ability (memory, senses, perception, etc.)
- 1mth – 3.5yrs
-
Denver Developmental Screening Test
- Motor, social/personal, and language skills
• Up to 6yrs
Nutrition during first two years
Poor nutrition
- Western diets can sometimes be low in vitamins A and C ( difficulties in motor ability) and iron ( deficits in cognitive performance)
-
Malnutrition
- Kwashiorkor
- Marasmus
- Severe learning and behaviour effects
-
Over-nutrition (excess calories/nutrients)
- Unhealthy food preferences
- Food often used as reward
• Moderate overweight not a medical concern in infants
Impairments in Growth: Low Birth-Weight
- Weighing less than 2.5kg; very low birth-weight – less than 1.5kg
- Maternal traits that increase risk: maternal malnourishment, smoking, alcohol, drugs during pregnancy, teenage or low SES mothers
- Small-for-gestational age more problematic than preterm
- Interventions include incubators, gentle stimulation and ‘kangaroo care’
Nonorganic Failure to Thrive
- Failure to grow for no apparent medical reason
- Highlights importance of love and emotional stimulation
Infant mortality
—The proportion of babies who die during the first year
—Indication of overall health of country’s children, related to parental income
—Australian infant mortality higher than 17 other developed countries (UNICEF, 2008)
Piaget’s stages of infant cognition
(see notes/ slide)
Visual preference
Tendency for infants to spend more time looking at one sight than another
- Young infants inherently interested in people, particularly faces – complexity in contours and curvature
- New research suggests babies are drawn to unusual and surprising events
- Stahl and Feigenson (2015)
Object Constancy/Permanence
- Belief that an object remains the same despite changes in the sensations it send to the eye
- Awareness that things continue to exist even when not visible (or present)
Depth perception- the visual cliff
- Six-month-old babies would approach “ledge” but avoided “drop”
- Demonstrated “depth perception”
- With mother’s encouragement, children will crawl over the visual
cliff
Auditory thinking
- Can localise sounds by 2mths, but can take longer to respond than older children or adults
- Prefer sounds in the middle range pitches most similar to human voices
- Early responses to sounds may be reflexive rather than coordinated
- Intermodal perception – ability to consistently combine sensory information; develops through infancy
Assessment of Piaget’s Theory
Criticisms:
- May confuse lack of motor skills with cognitive limitations • Object permanence demonstrated by “impossible test event”
- Memory limitations impact on performance
- New research suggests more continuity than change in cognitive development
- Piaget adopted a strict stage approach to development – cognitive development may be in fact be continuous
- Piaget rarely considered the role of culture in cognitive development
Behavioural Learning
- Babies born with ability to learn
- Classical Conditioning: involuntary responses to unconditioned stimuli are associated with new stimuli (conditioned stimuli)
- Operant Conditioning: learning based on reinforcement and punishment (e.g., infant babbles and mother claps and smiles so baby keeps babbling)
- Imitation: an attempt to communicate?
Language acquisition
- Two main language tasks:
- Mastering language structures
- Learning how language is used
- Phonology – infants must recognise the phonemes of their language
- Language environment influences early vocalisation – ‘babbling’
- Semantics (meaning) – first words are mainly nominals or labels
Early vocalisations
• Forms of pre-linguistic speech:
–Crying (Newborns)
–Cooing (6-8 weeks)
• Repeating vowel sounds – ‘ahhhh’
–Babbling (6-10 months)
• Repeating consonant sounds – ‘ma-ma-ma’, ‘da-da-da’
–Includes accidental and deliberate imitations of sounds without understanding their meaning
Semantics and First Words
referential style
expressive style
fast mapping
- Referential style: Speech refers to objects or events
-
Expressive style: Express feelings or relationships
- Children with a referential style make faster progress with vocabulary and grammar during second year
- Related to secure attachment
- Children with a referential style make faster progress with vocabulary and grammar during second year
- Fast mapping: act of learning a new concept after limited exposure
Influences on Language Acquisition
- Parents and other caregivers
- Pseudo-conversations, turn-taking, simplified speech
- Infant-directed speech
- “Parentese”
- Short sentences, simple speech with higher, more variable pitch
- Warmer tone
- Emphasis on specific words
- Repetition, paraphrasing
- Vocabulary development
- E.g., parent holds ball while saying “this is a ball”
Arguement for being born to talk
- Newborns can recognise sound of mother’s voice at birth
- What aspects of language are built into our brain through genetics and which are learned by listening in the womb?
- Researchers examining 12 pre-term infants found that the neural connections used in adult language processing are present early in development – supports hypothesis that we are hardwired to understand some aspects of speech
