Chapter 11 – Reading Notes
Developmental psychology: The study of continuity and change across the life span.
Zygote: A fertilized egg that contains chromosomes from both a sperm and an egg.
Zygote develops into an embryo at 2 weeks and then into a fetus at 8 weeks.
Each human sperm cell and each human egg cell contain 23 chromosomes which contains genes.
Genes are the blueprint for all biological development.
The 23 chromosomes can come in two variations: X or Y.
o Y chromosomes = Male
o X chromosomes = Female
Germinal stage: The 2-week period of prenatal development that begins at conception.
o Zygote begins to divide into 2 cells that divide into 4 and then divide into 8.
o Migrates back down the fallopian tube and implants itself in the wall of uterus.
o Male zygotes are especially unlikely to complete this.
Embryonic stage: A period that lasts from the second week until about the eighth week.
o Zygote continues to divide and its cells begin to differentiate.
o Zygote is known as an embryo: Has a beating heart, arms and legs.
o Embryos that have a Y chromosome begin to produce a hormone called testosterones
which masculinize their reproductive organs.
o X chromosome embryos do not produce testosterones and continue developing as a
Fetal stage: A period that lasts from the ninth week until birth.
o Embryo known as a fetus.
o It has a skeleton and muscles capable of movement.
o During last 3 months of fetal stage: fetus size increase, fat develops beneath its skin,
digestive & respiratory system mature.
o The brain develops; brain cells generate axons and dendrites.
o Undergo a process known as myelination.
o Myelination: The formation of fatty sheath around the axons of a neuron.
This process starts during fetal stage but doesn’t end for years; myelination of
the cortex continues into adulthood.
A newborn human’s brain is only 25% of its adult size.
Why are human beings born with such underdeveloped brains when other primates are not?
o Adult size brains are bigger and require a bigger head to house them. If a newborn’s
head were too close to its adult size, the baby wouldn’t be able to pass through its
mother’s birth canal.
o Humans’ greatest talent is its ability to adapt to a wide range of novel environment that
differ in terms of climate, social structure, and so on. Therefore, human beings arrive
with brains that do much of their developing within the very environments in which
they will function.
11.3 Development of a child starts as early as in the womb of the woman.
o The placenta is the organ that allows exchange of material between the mother and the
developing embryo/fetus. The food the mother eats during pregnancy can affect her
fetus. Child that receive insufficient nutrition during pregnancy tend to have both
physical and psychological problems.
Most notably an increased risk of schizophrenia and antisocial personality
It can also affect food preferences, children will tend to prefer the food that
their mother ate during pregnancy.
Teratogens: Agents that damage the process of development.
o Literally means “monster makers”.
o Most common is alcohol.
Fetal alcohol syndrome: Is a developmental disorder that stems from heavy alcohol use by the
mother during pregnancy.
o Children that suffer from FAS have a variety of distinctive facial features, brain
abnormalities and cognitive deficits.
o Some studies suggest that light drinking does not harm the fetus but there are no
medical consensuses about what a “safe” amount is.
Tabacco is another common teratogen.
o Have lower birth weights and are more likely to have perceptual and attentional
problems in childhood.
The fetus can hear its mother’s heartbeat, the gastrointestinal sounds associated with her
digestion, and her voice.
Infancy: The stage of development that begins at birth and lasts between 18 and 24 months.
Motor development: The emergence of the ability to execute physical actions such as reaching,
grasping, crawling, and walking.
Reflexes: Specific patterns of motor response that are triggered by specific patterns of sensory
o Rooting reflex = tendency for infants to move their mouths toward any object that
touches their cheek.
o Sucking reflex = tendency to suck any object that enters their mouths (omfg this is just
o These reflexes allow newborns to find their mother’s nipple and begin feeding.
The development of more sophisticated behaviours tends to obey two general rules.
o Cephalocaudal rule: Also known as the “top-to-bottom” rule which describes the
tendency for motor skills to emerge in sequence from the head to the feet.
Infants tend to gain control of their heads first, their arms and trunks next, and
their legs last.+96
o Proximodistal rule: Also known as the “inside-to-outside” rule which describes the
tendency for motor skills to emerge in sequence from the center to the periphery.
Babies learn to control their trunks before their elbows and knees, and they
learn to control their elbows and knees before their hands and feet. o Motor skills develop in an orderly sequence but not on a strict timetable. The timing of
these skills is influenced by the baby’s incentive for reaching, body weight, muscular
development and general level activity.
Cognitive development: The emergence of the ability to think and understand.
o Between infancy to adulthood, children must come to understand:
How the physical world works
How their minds represent it
How other minds represent it
Piaget suggested that cognitive development occurs in four stages:
o Sensorimotor stage (Birth – 2 years)
o Preoperational stage (2 – 6 years)
o Concrete operational stage (6 – 11 years)
o Formal operational stage (11 years and up)
Sensorimotor stage: A stage of development that begins at birth and lasts through infancy.
o Infants at this stage use their ability to sense and their ability to move to acquire info.
o Actively exploring their environment with their eyes, mouths and fingers, infants begin
to construct schemas (theories about or models of the way the world works).
o If infants realize that tugging at a toy makes it come closer, it will incorporate it into a
theory about how physical object behave. The infant will later use that theory when
he/she wants a different object to get closer. Piaget called this process assimilation
(when infants apply their schemas in novel situations).
o When an infant pull on a cat’s tail, the cat is more likely to run away. The infant will then
learn from it and adjusts their theory as they discover new things. Such as “inanimate
things come closer when I pull them”. Piaget called this process accommodation (when
infants revise their schemas in light of new information).
o Infants do not have a theory of object permanence (The idea that objects continue to
exist even when they are not visible). Infants act as thought objects stop existing the
moment they are out of sight. However studies show that infants have some
understanding of object permanence by the time they are just 4 months old.
Childhood: The stage of development that begins at about 18 to 24 months and lasts until
adolescence, which begins between 11 and 14 years.
According to Piaget, childhood consist of two stages:
o Preoperational stage: The stage of development that beings at about 2 years and ends
at about 6 years. During which the child learns about physical or “concrete” objects.
o Concrete operational stage: The stage of development that begins at about 6 years and
ends at about 11 years. During which the child learns various actions or “operations”
can affect or transform those objects.
o Piaget showed children a row of cups and asked them to place an egg in each.
Preoperational children were able to do this and they agreed that there were
just as many eggs as there were cups. However, if the eggs were removed and
spread out in a long line that extended beyond the row of cups, preoperational
children would incorrectly claim that there are more eggs than cups because the
row of egg is longer than the row of cups.
Concrete operational children would correctly report that the number of eggs
did not change. Piaget called this conservation (the notion that the quantitative
properties of an object are invariant despite changes in the object’s appearance). Centration: The tendency to focus on just one property of an object to the
exclusion of all others. Whereas adults can consider several properties at once,
children focus on the length of the line of eggs without simultaneously
considering the amount of space between each egg.
Reversibility: Children do not consider the fact that operation that made the line
of eggs longer could be reversed The eggs could be repositioned more closely
together and the line would become shorter.
Formal operational stage: The stage of development that begins around the age of 11 and lasts
o Children can solve nonphysical problems with ease.
o Childhood ends when formal operations begin and people who move on to this stage
are able to reason systematically about abstract concepts such as liberty and love and
about events that will happen, that might happened, and that never happened.
Egocentrism: The failure to understand that the world appears differently to different observers
Perceptions & Beliefs: A 3-year-old child may have trouble understanding that others may not
know what they know.
Desires & Emotions: At very young age, children understand that people have different desires.
However they take quite a long time to understand that other people may have emotional
reactions unlike their own.
Theory of Mind: The idea that human behaviour is guided by mental representations.
o Autism: A relatively rare disorder that affects approximately 1 in 2 500 children. Children
with autism typically have difficulty communicating with other people and making
friends, and some psychologists have suggested that this is because autistic children fail
to acquire a theory of mind. Although they are typically normal or better on most
intellectual dimensions, they have difficulty understanding inner life of other people.
They don’t seem to understand that people can have false beliefs, belief-based
emotions or self-conscious emotions.
o Deaf children whose parents do not know sign language: Children are slow to learn to
communicate because they do not have ready access to any form of conventional
language. This restriction slows the d