Chapter 5:
Biosocial Development
The First Two Years
Dr. M. Davis-Brantley
Body Size
• Infants double their birth weight by the
4th month and triple it by the end of the
1st year
• Fat is typically acquired to provide
storage for nourishment
– Stored nutrition comes into play to keep
the brain nourished if the child can not eat
due to sickness or teething
• Head-sparing
– The biological protection of the brain when
malnutrition temporarily affects body
growth
Sleep
• New babies typically spend 17 or more hours
sleeping
• Ample sleep correlates with brain maturation,
learning, emotional regulation, and
psychological adjustment
– Growth hormones are released during sleep
more so than during waking hours
• REM Sleep
– Rapid Eye Movement sleep: flickering of eyes,
dreaming and rapid brain waves
– Decreases significantly after 4 months
• Children are too immature in their brain,
digestion, and circadian rhythm to sleep on
command
Early Brain Development: Basic
Brain Structures
• Neuron—is a nerve cell of the central nervous
system (most neurons are in the brain)
– Most neurons are created during pregnancy and are
at their peak during mid-pregnancy
• Cortex
– The outer layer of the brain in humans that is the
primary location for most of our thinking, feeling,
and sensing
– Frontal cortex is in the front and is responsible for
executive functioning which includes planning, selfcontrol, and self-regulation (very immature at birth)
Early Brain Development: Basic
Brain Structures
• Neurons need to communicate with one
another in order to function
• They are connected by an intricate network of
nerve fibers
– Axon—is a nerve fiber that extends from the neuron
and transmits electrical impulses from that neurons
to the dendrites of the other neurons
– Dendrite—A nerve fiber that extends from a neuron
and receives electrical impulses transmitted from
other neurons via their axons
– Synapse—The intersection between the axon of
one neuron and the dendrites of other neurons
• Synapses are critical in communication links in the brain
Early Brain Development
• At birth, the brain contains more than 100
billion neurons, but not enough dendrites and
synapses
• During the first months and years, major
spurts of growth and refinement in axons,
dendrites, and synapses occur (connections
are being made)
• Transient Exuberance is the great increase in
the number of dendrites that occurs in an
infant’s brain over 1st 2 years of life
• Enables neurons to become connected and
communicate with other neurons within the
brain
– This leads to expanding of neurons and
connections in the brain
– Grows more during this time than any other time
throughout lifespan
Sensation and Perception
• Sensation—is the response to
sensory system when it detects a
stimulus
• Perception—The mental
processing of sensory information
when the brain interprets a
sensation
– The brain applies meaning to the
sight or sound that is sense
The Senses
• Listening
– Hearing is acute at birth and began during
the last trimester of pregnancy
– Hearing develops as child begins to
distinguish between different sounds
– Child also begins to mimic certain sounds
as she/he is learning language
• Looking
– Vision is the least mature sense at a birth
and newborns can focus on objects 4 to 30
inches
– With maturation of the visual cortex vision
improves
Motor Skills
•
•
Reflex—is a responsive
movement that seems automatic,
because it always occurs in
reaction to a specific stimulus
3 Classes of reflexes include:
1. Those that maintain oxygen supply
2. Those that maintain constant body
temp.
3. Reflexes that manage feeding
Gross Motor Skills
• Physical abilities involving large
body movements such a walking
and jumping
• B/n 8 and 10 months most infants
can lift their bodies and engage in
coordinating the movements of
their bodies to crawl, climb, and
eventually walk (after 10 months)
Fine Motor Skills
• Physical abilities involving small body
movements, especially of the hands
and fingers
– During first 2 months babies wave their
hands at dangling objects
– By 3 months they can usually touch the
object
– By 4 months some infants can actually
grab an item but their timing is not
accurate
– By 6 months child can grab and hold onto
an object
– After 6 months they can transfer objects
from one hand to another
– By 12 months they can coordinate and
manipulate
Baby’s Health
• Immunization is the process by which the
body’s immune system is stimulated to
defend against the attack of a contagious
disease
– The healthy person is given a small dose of the
inactive virus which stimulates that production of
antibodies
• Sudden Infant Death Syndrome (SIDS) is
when a seemingly health infant (at least 2
months of age) dies unexpectedly in her/his
sleep
– Decrease in amount of SIDS deaths has been linked
to not putting babies to sleep on their stomachs
and fewer parents smoking
– Ethnicity can play a significant role
Baby’s Health
• Nutrition
– Breast is Best
• For newborns, good nutrition starts with breast
milk
• Colostrum is a high-calorie fluid secreted by the
breasts at birth, 3 days later milk comes
• Breast milk is sterile & at body temp.
– Contains more iron, vitamins A & C, and other
important nutrients
– WHO recommends the child is breast fed
exclusively for 4-6 months
• Formula may be better when the mother is HIV+
Baby’s Health
•
Malnutrition
–
Protein-calorie malnutrition is a condition in which a person
does not consume sufficient food of any kind
Marasmus a disease of severe protein-calorie malnutrition
during early infancy, in which growth stops, body tissues
waste away, and the infant eventually dies
Kwashiorkor a disease of chronic malnutrition where deficiency
of protein causes the child’s face, legs, and abdomen to bloat
and makes the child more vulnerable to diseases such as
measles, diarrhea, influenza
–
–
•
3 consequences of chronic
malnourishment include:
1.
2.
Brains may not develop normally
The are no reserves to protect the child if disease
strikes
•
3.
Childhood diseases become far more lethal than
typically would be
The above stated disease can result