Chapter 3: Development Over
the Life Span
Section 1: From Conception
through the first year
Developmental Psychology: The Study
of Change
Def- study of human development
4 areas
Physical Development- actual growth
of the body, its sexual development,
the use of its muscles, & the
changes in the brain & sensory
organs
Cognitive Development- changes in
the way we think, reason, learn,
acquire language, & use knowledge
Social Development- changes in how
we relate to other people & develop
our own sense of self
Emotional Development- changes in
feelings & emotions & the
development of personality
Principles of Development
• Development follows a predictable pattern
• Individuals first develop general responses
then specific responses
• Development is a life long process
• Each stage has unique features
• Early development can be more important
than later development
• Critical periods- time periods
during which an individual can
learn specific behaviors most
easily (language)
• Sensitive periods- time during
development that is important
for learning certain behaviors
Growth
Prenatal  Infants (0-1 ½) 
Toddler (1 ½- 3)  Preschool (3-5)
 School age (6-11) 
Adolescents (12-20)
• Socialization – The process by which
children learn the attitudes &
behaviors expected of them by
society
Prenatal Development
• Divided into 3 month segments called
trimesters
1st trimester
Fertilized egg- 46 chromosomes (23
from each parent)
Prenatal Development
The Growing Fetus
Fertilization
30 Hours
6 weeks
4 months
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing
• Begins at conception when the male
sperm unites with the female ovum
(egg)
• The fertilized single celled egg is
called a zygote
Period of the Zygote (2 weeks)
Toxins either kill it or do nothing
• The zygote divides & in 10-14 days it
has become a cluster of cells that
attaches itself to the wall of the
uterus
• The outer part becomes the
placenta & umbilical cord, the inner
part is the embryo
Embryonic Stage
• Begins two weeks after conception
& lasts until the 8th week
All major organs are formed but not
developed
Bones start to calcify
Amniotic sack, placenta, & umbilical
cord develops
Prenatal testing can be done to
determine genetic defects
2nd trimester (Period of the Fetus)
Fetus starts to move
Gender is visible
Fully formed but only 14 inches long
By 28 weeks the nervous &
respiratory systems are developed
enough that a premature fetus could
survive
9 week fetus
3rd trimester
40 weeks is considered full
term
Weighs 6- 9 pounds
Lungs are matured & baby is
ready to be born
Harmful Influences
• German measles (rubella)- especially in
early pregnancy
–Can affect the fetus’s eyes, ears, &
heart
–Causes deafness
• X-rays or other radiation & toxic
chemicals such as lead or mercury
–Can cause fetal abnormalities &
deformities, attention problems, &
lower IQ scores
• Sexually transmitted diseases can cause
mental retardation, blindness, & other
physical disorders
• Cigarette smoking during pregnancy
increases the likelihood of miscarriage,
premature birth, abnormal fetal
heartbeat, & an underweight baby
–Increased infant sickness, Sudden
Infant Death Syndrome (SIDS), asthma,
& possibly hyperactivity & learning
difficulty
• Having more than 2 alcoholic drinks
everyday significantly increased the risk
of Fetal Alcohol Syndrome (FAS)
–FAS infants are smaller, have smaller
brains, facial deformities, are
uncoordinated, & mentally retarded
• Drugs other than alcohol can be
harmful whether illegal or OTCs
The Newborn
Baby has to breathe on its own,
maintain body temperature, get used
to new sights & sounds, & learn to
make their needs be known
Baby is helpless & depends on parents
for safety, warmth, hygiene, food, &
love
Timing of these stages
depends on baby’s central
nervous system
Rapid brain development from
birth- 3 years
• “The baby, assailed by eyes, ears,
nose, skin, and entrails at once,
feels that all is one great
blooming, buzzing confusion…”
•
• William James
The Principles of Psychology, 1890
The Infant’s World
• Motor reflexes
–Rooting
–Sucking
–Swallowing
–Moro
(“startle”)
–Babinski
–Grasp
–Stepping
• Table 74
Survival instincts
Reflexes ensure survival
Gag reflex- to breathe
Sucking- nourishment
Startle in response to a loud noise,
sudden change in position & grasp your
finger if you stroke the palm
• Perceptual Abilities
–Smell, see, hear, taste, & touch
–Visual range is about 8 inches
–Distinguish contrasts, shadows, &
edges
–Discriminate their mother by smell,
sight, & voice
–Has a preference for faces
The Remarkable Newborn
Sensory Capacities
Visual Preferences in Newborns
• Infants spend more
time looking at
patterns than solids.
• Infants spend the most
time looking at a
drawing of a human
face.
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing
Born to perceive
Newborns can see but best 8 -14
inches away
Better by 3 months
Follow movement & people
Develop hand eye coordination
Reach for & grasp dangling objects
Ability to hear starts in the womb
Human voices & music sound
familiar
Soothing tones help infants stop
crying
Begin to coo & babble- evolve into
words
The Remarkable Newborn
Sensitivity to Number
Can Infants Add and Subtract?
• Infants saw a sequence
of events that
illustrated addition or
subtraction.
• Then they saw a correct
or incorrect outcome
(2-1=2, for example).
• The infant looked longer
at outcomes that were
incorrect.
Kassin, Essentials of Psychology - ©2004 Prentice Hall Publishing
Babies prefer sweet tastes
Touch is important
Like to be wrapped snugly in a
blanket & to be hugged
Babies tend to be cross eyed
because they have little control
over their eye muscles
6 months perceive depth
• Many aspects of maturation depend
on cultural customs
–Sleep arrangements
Attachment
• Emotional attachment is a universal
capacity of all primates & is important for
health & survival through life
• By becoming attached to a caregiver,
children can gain a secure base from
which they can explore the environment
& a haven of safety to return to when
they are afraid
• Physical Appearance of babies fosters
attachment to them- heart beats faster &
eyes dilate
• Comfort contact
–Attachment begins with physical
touching & cuddling between infant &
parent
Separation & Security
• Between 6-8 months, babies become
weary or fearful of strangers
–They will wail if they are put in
unfamiliar setting of left with an
unfamiliar person
–Separation anxiety if the primary
caretaker temporarily leaves them
Mary Ainsworth & the Strange Situation
•
•
•
•
•
•
•
•
Mother brings baby in room with lots of toys
Stranger comes in & attempts to play with baby
Mom leaves baby with a stranger
Mom returns & plays with child
Stranger leaves
Mom leaves again (baby is alone)
Mom returns
Observers note how baby behaves with mom,
with stranger, & alone
Reaction/Attachment Categories
• Securely attached
–Cry or protest if the mother leaves
the room & welcome her back &
then play happily again
–Balance of exploration & play with
desire to remain near their
caregivers in an unfamiliar setting
–Linked to confidence, successful
relationships with friends & doing
well in school
–Can override the effects of an
unstable home environment
• Insecurely attached
– 2 types
•Avoidant
–Not caring if the mother leaves
the room & treats the stranger
the same as mom
•Anxious or ambivalent
–Resists contact with the
mother at reunion but
protests loudly if she leaves
–Quality of attachment depends on
how sensitive the parents are to
the infants need for contact
–Babies with no attachment do not
learn to cope with the stresses of
everyday life
What Causes Insecure Attachment?
• Results from the way mothers treat their
babies during the first year
• Not affected by being in child care more than
20 hours a week
• Truly abusive, neglectful, or erratic parenting
• Child’s temperament
• Stressful circumstances in the child’s family