Transcript Physical Development in Infancy & Early Childhood

Physical Development in
Infancy & Early Childhood
Chapter 3
Reflexes
Babies born with host of unlearned
reflexes
Triggered by specific stimuli & are adaptive
Sucking (feeding)
Blink (protect eyes)
Moro (aids clinging behavior)
Some are precursors to voluntary behavior
Palmar (grasping)
Stepping (walking)
Infant Health
Apgar score indicates overall health
Vital signs (heart rate)
 Neonatal Behavioral Assessment Scale
Reflexes, hearing, vision,alertness, irritability
and consolability
Newborn States
4 hour cycle between
Alert inactivity
Waking activity
Crying (2-3 hours/day)
Basic v. mad v. pain
Sleeping (16-18 hours/day)
Cycles of 3 hours of sleep, 1 hour of wakefulness
50% REM first 4 months (20% for adults)
Temperament
(not all babies are alike)
Consistent style of behavior & emotional
responding (seen upon birth)
Emotionality
Activity
Sociability
Highly heritable (~60%) & stable
NOT fate as environment also plays a role
(Kagan)
Physical Growth
Rapid growth
40% energy spent growing
Double weight by 3 months, triple by 12
months
Size closely related to biological parents
Physical Growth
Diet
Babies eat lots! (50 calories/lb)
Adults consume 15-20 calories/lb
Breast feeding best (1st year)
Antibodies protect against illness
Less digestive problems
Transition to solid food easier
No contamination
• Slow introduction of solid foods
Early Brain Development
After conception:
3 weeks: the neural plate forms
4 weeks: folds into a tube (brain & spinal cord)
10 weeks: neurons are produced until week 28
(4,000/second)
Neurons migrate to various locations in layers
Deepest layers form first, then the next layer, etc.
7 months post conception and all layers in place
4 months post conception: myelin beings to form
Early Brain Development
After birth brain grows rapidly
Axons, dendrites grow longer
Make many new connections with other
neurons
Specialization begins
Frontal lobe: personality, judgement
Left hemisphere: language
Depends to some extent on experience
Early Brain Development
Brain plasticity: flexible structure & function?
Nature nurture issue
Brain has some plasticity
Neurons can reorganize and change function
Plasticity may also express itself through unique
neuronal connection density due to experience
• Adult exposed to music/athletics at an early age
Brain also has unalterable organizational plan
Visual cortex always at back of brain
Areas for hearing near temporal lobe
Locomotion
Dynamic Systems Theory
Motor development involves learning &
coordinating many skills together (practice)
Posture & balance develops in a few months
• Visual cues and inner-ear mechanism used to adjust
posture
Stepping occurs automatically at 7 months
Walking develops around 15 months
• Use perceptual cues to walk/crawl
Fine Motor Skills
Reaching & grasping
Birth grasping with fingers (not thumb)
4 months reaching & grasping
5-6 months coordinating both hands
7 months grasping with finders & thumb
Increasing dexterity with age
Handedness
90% of people are right handed
Most infants show no preference until ~1
year
Heredity key
Culture/values
Perception
Smell & taste
Babies born with good sense of smell
React to pleasant/unpleasant odors in obvious
ways
Recognize familiar odors (e.g., mother)
Babies also have good sense of taste
Perception
Touch & pain
Babies are sensitive to touch and pain
Respond reflexively to touch
React strongly to painful stimuli (cry)
Hearing (good at birth and develops)
Best hear pitches in range of human speech
Can differentiate different speech sounds
4.5 months can recognize their name
Use sound to locate objects in space
Perception
Sight
Visual acuity not as good as adults
Rapidly develops (12 months = adults)
Color vision develops within a few months
Newborns perceive few colors
Cones in visual cortex begin functioning soon
• 4 months old = adults
Perception
Depth
Can perceive depth by 5 months of age
Use various cues to depth
Retinal disparity
Motion
Sound
Sensory integration
Infants understand connections among
sensations
Self-Awareness
Develops around 18 months
2 years old all kids have self-concept
Touch their nose with red mark
Look at photos of themselves more
Declare their possessions as part of their selfconcept
• “Mine!”
Theory of Mind
Phase 1: aware of desires causing behavior
Age 2
Phase 2: can distinguish mental from
physical world
Age 3
Phase 3: understand beliefs cause behavior
in self & others
Age 4