DEVELOPMENTAL GRADED A+ 2025/2026 EXAM ON
PSYCHOLOGY NEW EDITION
Infancy - Birth to about 2 years; refers to period before child can speak
Infant weight - By 5 months, birthweight has doubled; by 1 year, it has tripled; by 2 years, it has
quadrupled
Infant length - On average, by end of year 1, baby is 30 inches tall; by end of year 2, child is 3 feet tall
Body proportions - Not all body parts grow at the same rate (head grows slower)
Cephalocaudal principle - States that growth follows a direction and pattern that begins with the
head and upper body parts and then proceeds to the rest of the body (head to toe)
Proximodistal principle - States that development proceeds from the center of the body outward
(from middle to extremities)
Principle of hierarchical integration - States that simple skills typically develop separately and
independently, but that these simple skills are integrated into more complex ones (sweeping motions
develop before pinching motions)
Principles of the independence of systems - Suggests that different body systems grow at different
rates (digestive and respiratory systems develop before reproductive)
Infants are born with ___________________ neurons - 100-200 billion
Over the first 2 years of life, networks of neurons become... - Increasingly complex and
interconnected
Synaptic pruning - Cells that are not needed die off
Nervous system growth - Brain triples in weight in first 2 years of life; neurons increase in size; axons
become coated with myelin (to speed transmission of impulses)
, Neurons arranged by function - Some move to cerebral cortex, the upper layer of brain; some go to
subcortical levels, where they regulate basic function
Shaken baby syndrome - Damages brain and spinal cord; typically leads to death; 600-1400 cases in
US per year
Plasticity - Degree to which the brain is susceptible to experience; greatest during first several years
of life; brain is more resilient
Sensitive period - Time when organism is particularly susceptible to environmental influences
Brain development in infants is best supported by... - Cuddling, talking/singing, and playing
Rhythms - Repetitive, cyclical patterns of behavior
States - The degree of awareness an infant displays to both internal and external stimulation
Infant sleep - Sleep 16-17 hours daily; sleep stages (circadian rhythms) are out of sync/opposite to
parents during early infancy; most do not sleep through the night for several months
Infant REM sleep - REM is associated with dreaming; REM takes up half of infant's sleep; infant brain
waves are different than the dreaming sleep of adults
Autostimulation - The brain stimulating itself
Sudden infant death syndrome - Unexplained death of a seemingly healthy baby; most susceptible
from 1 month to 1 year; affects about 2500 infants in US yearly; no cause has been found; leading
cause of death in first year of life
APA suggestions for infant sleep - Before a baby can flip themselves, the APA recommends that they
sleep on their back in a crib with nothing else (no blankets, stuffed animals, etc.)
Reflexes - Unlearned, organized, involuntary responses that occur automatically in the presence of
certain stimuli (some stay throughout life, others disappear)
PSYCHOLOGY NEW EDITION
Infancy - Birth to about 2 years; refers to period before child can speak
Infant weight - By 5 months, birthweight has doubled; by 1 year, it has tripled; by 2 years, it has
quadrupled
Infant length - On average, by end of year 1, baby is 30 inches tall; by end of year 2, child is 3 feet tall
Body proportions - Not all body parts grow at the same rate (head grows slower)
Cephalocaudal principle - States that growth follows a direction and pattern that begins with the
head and upper body parts and then proceeds to the rest of the body (head to toe)
Proximodistal principle - States that development proceeds from the center of the body outward
(from middle to extremities)
Principle of hierarchical integration - States that simple skills typically develop separately and
independently, but that these simple skills are integrated into more complex ones (sweeping motions
develop before pinching motions)
Principles of the independence of systems - Suggests that different body systems grow at different
rates (digestive and respiratory systems develop before reproductive)
Infants are born with ___________________ neurons - 100-200 billion
Over the first 2 years of life, networks of neurons become... - Increasingly complex and
interconnected
Synaptic pruning - Cells that are not needed die off
Nervous system growth - Brain triples in weight in first 2 years of life; neurons increase in size; axons
become coated with myelin (to speed transmission of impulses)
, Neurons arranged by function - Some move to cerebral cortex, the upper layer of brain; some go to
subcortical levels, where they regulate basic function
Shaken baby syndrome - Damages brain and spinal cord; typically leads to death; 600-1400 cases in
US per year
Plasticity - Degree to which the brain is susceptible to experience; greatest during first several years
of life; brain is more resilient
Sensitive period - Time when organism is particularly susceptible to environmental influences
Brain development in infants is best supported by... - Cuddling, talking/singing, and playing
Rhythms - Repetitive, cyclical patterns of behavior
States - The degree of awareness an infant displays to both internal and external stimulation
Infant sleep - Sleep 16-17 hours daily; sleep stages (circadian rhythms) are out of sync/opposite to
parents during early infancy; most do not sleep through the night for several months
Infant REM sleep - REM is associated with dreaming; REM takes up half of infant's sleep; infant brain
waves are different than the dreaming sleep of adults
Autostimulation - The brain stimulating itself
Sudden infant death syndrome - Unexplained death of a seemingly healthy baby; most susceptible
from 1 month to 1 year; affects about 2500 infants in US yearly; no cause has been found; leading
cause of death in first year of life
APA suggestions for infant sleep - Before a baby can flip themselves, the APA recommends that they
sleep on their back in a crib with nothing else (no blankets, stuffed animals, etc.)
Reflexes - Unlearned, organized, involuntary responses that occur automatically in the presence of
certain stimuli (some stay throughout life, others disappear)
