LIFESPAN DEVELOPMENT
• At Birth: The head is about 25% of the
Coverage: infant’s total body length.
• Infancy and Toddlerhood • In the Womb: The head makes up about 50%
• The Brain in the First Two Years of total length.
• Infant Sleep • By Age 25: The head comprises about 20%
• From Reflexes to Voluntary of the person's total length.
Movements
• Motor Development
The Brain in the First Two Years
• Sensory Capacities Neurons and Brain Growth
• Nutrition • Neuron Count: Babies are born with
• Global Considerations and approximately 85 billion neurons (brain cells),
Malnutrition which are responsible for storing and
• Piaget and the Sensorimotor Stage transmitting information (Huttenlocher &
• Language Dabholkar, 1997).
• Components of Language • Neurons at Birth: Neurons are not fully
• Language Developmental mature at birth but undergo significant
Progression development in the first two years.
• Theories of Language Development Brain Processes
• Temperament • Dendrite Proliferation: Dendrites (branches
• Infant Emotions on neurons that collect information) undergo a
• Forming Attachments period of rapid growth. By age 2, a single
• Erikson: Trust vs. Mistrust neuron may have thousands of dendrites.
• Synaptogenesis: The formation of new
• Mary Ainsworth and the Strange
connections between neurons, known as
Situation Technique
synaptic blooming, occurs during infancy and
• Erikson: Autonomy vs. Shame and
toddlerhood.
Doubt and Toddlerhood
Infancy • Synaptic Pruning: Neural connections are
• Measuring Infant Development reduced, strengthening the connections that
Focus on Early Development are used often. Around 40% of connections
• Infancy and toddlerhood (first two years) are will be lost, making the brain more efficient
highly significant in physical, cognitive, and (Kolb & Whishaw, 2011).
socioemotional development. Myelination
• Researchers have emphasized this period • Myelin Development: Myelin, a fatty
due to dramatic changes and their long-lasting substance that coats axons (nerve fibers),
impact, though some argue the significance is speeds up nerve signal transmission and
overstated (Bruer, 1999). improves coordination and thought processes.
Physical Growth Myelination continues into adolescence but is
• Newborn Characteristics: most dramatic during the first few years
o Average weight: 7.5 pounds (range: 5- (Carlson, 2014).
10 pounds). Brain Growth Milestones
o Average length: 20 inches. • At Birth: Brain weighs about 250 grams (0.5
o Weight Loss After Birth: Newborns pounds).
typically lose about 5% of body weight • By 1 Year: Brain grows to 750 grams.
in the first few days, which is • Adult Size: Newborn brain is about 33% of
temporary and mostly goes unnoticed. adult brain size, and by 90 days, it's already
• Rapid Growth in the First Two Years: 55% of adult size (Holland et al., 2014).
o By 4 months: Infant's weight doubles. • Neural Activity: Most neural activity occurs in
o By 1 year: Weight triples from birth. the cortex, the outer layer of the brain
o By 2 years: Weight quadruples, involved in voluntary actions and thinking.
typically ranging between 20-40 Brain Structure
pounds. • Cortex Divisions
o Length: o Frontal Lobe: Thinking, planning,
▪ 1 year old: Around 29.5 inches. memory, and judgment.
▪ 2 years old: Around 34.4 o Parietal Lobe: Touch sensation
inches (Bloem, 2007). processing.
Body Proportions: o Occipital Lobe: Visual information
processing.
1|Hikamac chi
, LIFESPAN DEVELOPMENT
o Temporal Lobe: Hearing and o Unknown Cause: Deaths where the
language processing (Jarrett, 2015). cause remains unexplained due to
• Developmental Differences insufficient investigation. In 2017, 1300
o Primary motor areas (movement infants died from unknown causes
control) develop earlier than primary (CDC, 2019).
sensory areas (sensation processing). o Accidental Suffocation and
o The prefrontal cortex (behind the Strangulation in Bed: Includes
forehead) is the least developed in suffocation by soft bedding, being
infancy but becomes important for rolled on by another person, being
emotion regulation, planning, and wedged between objects, or
judgment as it matures. strangulation by crib railings. In 2017,
Lateralization 900 infants died from these causes
• The process where specific functions become (CDC, 2019).
more localized in one hemisphere of the brain. SUID Trends
o Left Hemisphere: Language • SUID Death Rate: The rate of SUID deaths
production. decreased after the Back to Sleep campaign
o Right Hemisphere: Visuospatial (1994) and safe sleep guidelines, such as
abilities (Springer & Deutsch, 1993). placing infants on their backs (nonprone
• Lateralization develops over time and begins position).
in fetuses and infants (Chi et al., 1997). • Accidental Suffocation: Deaths from
Neuroplasticity accidental suffocation and strangulation in
• The brain’s ability to physically and chemically bed have increased since 1998, reaching the
change in response to environmental changes highest rate in 2017.
and to repair injuries. Bed-Sharing and SIDS Risk
• Adaptability: Brain can reorganize to perform • Risk Factors: Studies show that infants
damaged functions. under 3 months are more likely to die of
• Effect of Age: Neuroplasticity is more SIDS if they bed-share with parents. Bed-
pronounced in infants than in adults (Kolb & sharing increases SIDS risk, even without
Whishaw, 2011). smoking or drug use.
• Study Findings: Infants who slept in a
Infant Sleep separate sleep space but in the same room as
parents had a lower risk of SIDS (Carpenter et
Infant Sleep Patterns al., 2013).
• Newborn Sleep: A newborn typically sleeps • Cultural Differences: In some cultures, co-
around 16.5 hours per day in multiple sleep sleeping (bed-sharing) is common, but
periods (polyphasic sleep) (Salkind, 2005). parents often use hard surfaces like floor mats
• Sleep by Age: to minimize suffocation risks (Nelson et al.,
o 1 Month: Approximately 15 hours per 2000).
day. Recommendations for Safe Sleep
o 6 Months: Around 14 hours per day. • Infants should sleep on their backs, in a
o 2 Years: About 10 hours per day. separate sleep surface (such as a crib),
• REM Sleep: Newborns spend about 50% of without soft bedding, and avoid bed-sharing to
their sleep in Rapid Eye Movement (REM) reduce the risk of SIDS and accidental
phase, which decreases to 25%-30% as they suffocation.
grow.
Sudden Unexpected Infant Deaths (SUID) Reflexes to Voluntary Movements
• SUID refers to deaths of infants under 1 year
of age with no immediately obvious cause Infant Reflexes
(CDC, 2019). • Reflexes are involuntary movements in
• Types of SUID response to certain stimuli.
o Sudden Infant Death Syndrome • Reflexes help in initial survival and provide
(SIDS): The leading cause of death for insights into the development of the nervous
infants 1-12 months old. No clear system.
cause found after medical Common Infant Reflexes
investigation. SIDS may be linked to • Sucking Reflex: Baby sucks on anything that
abnormalities in the brainstem, which touches their lips (important for feeding).
regulates breathing (Weekes-
Shackelford & Shackelford, 2005).
2|Hikamac chi
• At Birth: The head is about 25% of the
Coverage: infant’s total body length.
• Infancy and Toddlerhood • In the Womb: The head makes up about 50%
• The Brain in the First Two Years of total length.
• Infant Sleep • By Age 25: The head comprises about 20%
• From Reflexes to Voluntary of the person's total length.
Movements
• Motor Development
The Brain in the First Two Years
• Sensory Capacities Neurons and Brain Growth
• Nutrition • Neuron Count: Babies are born with
• Global Considerations and approximately 85 billion neurons (brain cells),
Malnutrition which are responsible for storing and
• Piaget and the Sensorimotor Stage transmitting information (Huttenlocher &
• Language Dabholkar, 1997).
• Components of Language • Neurons at Birth: Neurons are not fully
• Language Developmental mature at birth but undergo significant
Progression development in the first two years.
• Theories of Language Development Brain Processes
• Temperament • Dendrite Proliferation: Dendrites (branches
• Infant Emotions on neurons that collect information) undergo a
• Forming Attachments period of rapid growth. By age 2, a single
• Erikson: Trust vs. Mistrust neuron may have thousands of dendrites.
• Synaptogenesis: The formation of new
• Mary Ainsworth and the Strange
connections between neurons, known as
Situation Technique
synaptic blooming, occurs during infancy and
• Erikson: Autonomy vs. Shame and
toddlerhood.
Doubt and Toddlerhood
Infancy • Synaptic Pruning: Neural connections are
• Measuring Infant Development reduced, strengthening the connections that
Focus on Early Development are used often. Around 40% of connections
• Infancy and toddlerhood (first two years) are will be lost, making the brain more efficient
highly significant in physical, cognitive, and (Kolb & Whishaw, 2011).
socioemotional development. Myelination
• Researchers have emphasized this period • Myelin Development: Myelin, a fatty
due to dramatic changes and their long-lasting substance that coats axons (nerve fibers),
impact, though some argue the significance is speeds up nerve signal transmission and
overstated (Bruer, 1999). improves coordination and thought processes.
Physical Growth Myelination continues into adolescence but is
• Newborn Characteristics: most dramatic during the first few years
o Average weight: 7.5 pounds (range: 5- (Carlson, 2014).
10 pounds). Brain Growth Milestones
o Average length: 20 inches. • At Birth: Brain weighs about 250 grams (0.5
o Weight Loss After Birth: Newborns pounds).
typically lose about 5% of body weight • By 1 Year: Brain grows to 750 grams.
in the first few days, which is • Adult Size: Newborn brain is about 33% of
temporary and mostly goes unnoticed. adult brain size, and by 90 days, it's already
• Rapid Growth in the First Two Years: 55% of adult size (Holland et al., 2014).
o By 4 months: Infant's weight doubles. • Neural Activity: Most neural activity occurs in
o By 1 year: Weight triples from birth. the cortex, the outer layer of the brain
o By 2 years: Weight quadruples, involved in voluntary actions and thinking.
typically ranging between 20-40 Brain Structure
pounds. • Cortex Divisions
o Length: o Frontal Lobe: Thinking, planning,
▪ 1 year old: Around 29.5 inches. memory, and judgment.
▪ 2 years old: Around 34.4 o Parietal Lobe: Touch sensation
inches (Bloem, 2007). processing.
Body Proportions: o Occipital Lobe: Visual information
processing.
1|Hikamac chi
, LIFESPAN DEVELOPMENT
o Temporal Lobe: Hearing and o Unknown Cause: Deaths where the
language processing (Jarrett, 2015). cause remains unexplained due to
• Developmental Differences insufficient investigation. In 2017, 1300
o Primary motor areas (movement infants died from unknown causes
control) develop earlier than primary (CDC, 2019).
sensory areas (sensation processing). o Accidental Suffocation and
o The prefrontal cortex (behind the Strangulation in Bed: Includes
forehead) is the least developed in suffocation by soft bedding, being
infancy but becomes important for rolled on by another person, being
emotion regulation, planning, and wedged between objects, or
judgment as it matures. strangulation by crib railings. In 2017,
Lateralization 900 infants died from these causes
• The process where specific functions become (CDC, 2019).
more localized in one hemisphere of the brain. SUID Trends
o Left Hemisphere: Language • SUID Death Rate: The rate of SUID deaths
production. decreased after the Back to Sleep campaign
o Right Hemisphere: Visuospatial (1994) and safe sleep guidelines, such as
abilities (Springer & Deutsch, 1993). placing infants on their backs (nonprone
• Lateralization develops over time and begins position).
in fetuses and infants (Chi et al., 1997). • Accidental Suffocation: Deaths from
Neuroplasticity accidental suffocation and strangulation in
• The brain’s ability to physically and chemically bed have increased since 1998, reaching the
change in response to environmental changes highest rate in 2017.
and to repair injuries. Bed-Sharing and SIDS Risk
• Adaptability: Brain can reorganize to perform • Risk Factors: Studies show that infants
damaged functions. under 3 months are more likely to die of
• Effect of Age: Neuroplasticity is more SIDS if they bed-share with parents. Bed-
pronounced in infants than in adults (Kolb & sharing increases SIDS risk, even without
Whishaw, 2011). smoking or drug use.
• Study Findings: Infants who slept in a
Infant Sleep separate sleep space but in the same room as
parents had a lower risk of SIDS (Carpenter et
Infant Sleep Patterns al., 2013).
• Newborn Sleep: A newborn typically sleeps • Cultural Differences: In some cultures, co-
around 16.5 hours per day in multiple sleep sleeping (bed-sharing) is common, but
periods (polyphasic sleep) (Salkind, 2005). parents often use hard surfaces like floor mats
• Sleep by Age: to minimize suffocation risks (Nelson et al.,
o 1 Month: Approximately 15 hours per 2000).
day. Recommendations for Safe Sleep
o 6 Months: Around 14 hours per day. • Infants should sleep on their backs, in a
o 2 Years: About 10 hours per day. separate sleep surface (such as a crib),
• REM Sleep: Newborns spend about 50% of without soft bedding, and avoid bed-sharing to
their sleep in Rapid Eye Movement (REM) reduce the risk of SIDS and accidental
phase, which decreases to 25%-30% as they suffocation.
grow.
Sudden Unexpected Infant Deaths (SUID) Reflexes to Voluntary Movements
• SUID refers to deaths of infants under 1 year
of age with no immediately obvious cause Infant Reflexes
(CDC, 2019). • Reflexes are involuntary movements in
• Types of SUID response to certain stimuli.
o Sudden Infant Death Syndrome • Reflexes help in initial survival and provide
(SIDS): The leading cause of death for insights into the development of the nervous
infants 1-12 months old. No clear system.
cause found after medical Common Infant Reflexes
investigation. SIDS may be linked to • Sucking Reflex: Baby sucks on anything that
abnormalities in the brainstem, which touches their lips (important for feeding).
regulates breathing (Weekes-
Shackelford & Shackelford, 2005).
2|Hikamac chi
