Infancy and Toddlerhood

Physical Growth

• Growth spurts
  • up to 1/2 inch in a day
• Height doubles in 1 yr
• "Baby fat" for temperature regulation
• Cephalocaudal trend
  • head growth
• Proximodistal trend
  • center-out growth

Neurons

• 100-200 billion neurons in the brain, many with thousands of connections
• Connections called a synapse
• Communicate with neurotransmitters, e.g. dopamine.
• Glial cells responsible for fatty sheath known as myelin

Synaptic pruning

• Prenatal development creates more neurons than needed
• Overabundance of synapses
• Unused neurons dies to make space
• Unused synapses are pruned to be used later
  • Improves connections --sensitive periods
• ~86 billion neurons as an adult

Molding a living sculpture

"Mature" brains

To keep in mind all semester:

• Debated, when is a brain "fully developed" (if ever?)
  • End of motor development? (~16 yrs old)
  • End of synaptic pruning? (mid-20s)
  • End of myelination (~ age 32)
  • End of plasticity?

Cerebral Cortex Regions

Text

Breast v. Bottle

Breastfeeding

• Correct balance of macro/micro nutrients
• protects against disease
• short-term health benefits
• Digestable
• Easier transition to solid food
• Less reliant on economic/political factors (e.g. more accessible, no contaminants)
• Not everyone can do it

Bottle feeding

• Can supplement breast milk with formula
• Same attachment and emotional adjustment
• little long-term impact (esp after 1st year)
• More freedom for parents
• More & less social stigma

Motor Development

Gross-motor Development

• Using large muscles, allows movement
• Crawling, standing, walking jumping, running
• Assessed by Physical Therapists (PT)

Fine-motor Development

• Small precise movements
• Milestones
  • Ulnar Grasp (3-4mo)- whole hand
  • Hand-to-hand Transfer (4-5mo)
  • Pincer Grasp (8-11mo) - finger & thumb
• Assess with Occupational Therapists (OT)

Culture and Motor Development

Kipsigis of Kenya

• Children are almost always kept upright
• Children skip crawling, much faster gross motor development
•  

In the west

• Move from tummy-time to laying on back (SIDS)
• Slower gross-motor development

Central Asia

• Gahvora craddle (Karasik, 2016)

Early Perception

Hearing

• Music (4-7mo)
• Speech (~5mo)

Statistical learning- listen for patterns, will learn meaning later

Vision

• 3 days: basic face perception
• 2-3 wks: Movement
• 2 mos: focus and color perception.                             complex face perception
• 3 mo: facial recognition
• 5 mo onward: facial expressions
• 7 mo: full depth perception

differentiation theory-- Infants look for stable reference points

Classical Conditioning

Remember Pavlov's Dogs?

• UCS +NS = UCR
• NS becomes CS
• CS = CR

Infants are receptive to classical conditioning

• Little Albert Experiment - John B. Watson (1920)

Operant Conditioning

Reinforcer

• Increases probability that  behavior will occur again by
  • presenting desirable stimulus
  • removing unpleasant stimulus

Punishment

• Reduces probability that behavior will occur again by
  • presenting unpleasant stimulus
  • removing desirable stimulus

Theory of Attatchment

• John Bowlby (1969)- theory rooted in psychoanalysis
  • Infant attatchment is basis of future relationships
  • Form "Internal working model" of expectations
    • Preattachment Phase - 0 to 6wks
    • Attatchment in the making - 6wk to ~7mo
    • Clear-cut attachment- ~7mo to ~21 mo
    • Formation of reciprocal relationship- onward

• Attachment - A long-term affectionate relationship
• Harlow (1959) - Rhesus monkey attachment study

The Strange Situation

• Ainsworth (1978)- measurement of infant attachment

Initially, yield 4 types of Attachment:

• Secure

• Anxious/Avoidant

• Ambivalent/Resistant

• Disorganized/Disoriented

Attatchment Theory

• Impact of SES
  • Poverty and life stressors promote insecure attatchment
• Impact o Culture
  • Individualistic (eg US) vs Collectivist (eg Japanese)

Big Moods

• Self-conscious emotions- around 1.5 - 3yrs old
  • Shame
  • Embarrassment
  • Guilt
  • Pride
  • Envy
• Need to understand adult instructions on when/how to feel emotions
• Need a sense of "self"
• "Categorical Self"

Development of "Self"

• What is the "self" again? Is there such a thing as an individual?
• self-recognition & self-awareness
  • Mirror/rouge study (Lewis & Brooks-Gunn, 1979)

• Self-control; self-regulation
  • Delay of gratification – Stanford Marshmallow Experiment (Mischel 1970)

Structure of Temperament

• Thomas and Chess (1991) study
  • Easy: 40%
    • Good mood and quick to adapt. More social.
  • Difficult: 10%
    • Irregular routines and frequent crying
  • Slow-to-warm-up: 15%
    • low activity, somewhat negative
  • Unclassified: 35%
• Mix of Emotionality, Socialibility, and Activity level
• Stability is low in infancy and toddlerhood

Facial Expressions

• Still face Experiment (Tronick et al 1975)
  • Infants connect facial expressions /w emotions, social building block
• Newborn babies imitate some expressions? Inconsistent findings
• A study by Meltzoff & Moore (1977)
• Mirror neurons- in primates