chapter 11: the development of body, thought, language Flashcards
developmental psychology
the study of changes that occur in people’s abilities and suppositions as they grow older
how much spent do men release in each ejaculation
about 250 million
where is the egg when it’s impregnated
in the Fallopian tube which connects the ovaries to the uterus (womb)
three phases of the prenatal period
zygotic (germinal), embryonic, foetal
how long is the zygotic phase
the first two weeks
how many zygotes don’t survive the earliest phase of development and how many of those don’t survive later stages
40% early stages, 1/3 spontaneous abortion
when do embryo’s major organ systems develop
in the embryonic phase
when does the embryonic phase happen
from the third to about the eight weeks after conception
how does the embryo receive nutrition from the mother’s blood stream
via the umbilical cord and placenta
when does the foetal phase happen
from about 9 weeks until the birth (38 weeks after contraception)
what happens in the foetal phase
growth and refinement of organs and body structure
what are the sizes of the foetus at 3 months
it’s about 2.5 inches long and weighs about half an ounce
how large is the baby when it’s born
about 20 inches long and about 7.5 pounds
what percentage makes the head for a baby and for an adult?
20% for a baby and 12% for the adult
cephalocaudal development
change in proportion, with the development progressing essential from head to foot
what happens by the end of 12th week
all the organs are formed and are in the same proportion to each other as in a full-term newborn, just smaller
when does external genitalia begin to differentiate between males and females and when is it fully developed
differentiates at 9 weeks, fully formed at 12
when does the embryo begin to move, when does the activity increase and when do women start feeling it move
begins to move at 8 weeks, activity increases at 12, women feel it in the 5th month
when do infants start responding to their mothers’ heart beats and voice
by 6 months
what are teratogens
environmental agents that cause harm during prenatal development, most are in the form of substances that get into the baby’s system through the umbilical cord - weed, cocaine, heroin, antibiotics, antidepressants, sex hormones, alcohol, tobacco
in what period can teratogens affect the course of development of organs the most
between the 3rd and 8th week
what happened with the drug thalidomide
it was prescribed in the 1960s for morning sickness, woman who took it between 3rd and 8th week had children with deformed limbs and damage to other organs, but women who took it later in pregnancy didn’t
what happens to babies whose mothers had poor diets during pregnancy
tend to have low birth weights, but then grow up to become overweight or obese during childhood - thrifty phenotypes storing more fat than children whose prenatal diets were more nutritious
what characteristics do children who were prenatally exposed to higher levels of stress hormone have?
higher anxiety, fearfulness, temperamental difficulty, impulsitivity, reduced executive functions, reduced executive functions, impaired attention, higher aggression, risk taking
how long does infancy last
roughly the first 18 to 24 months after birth
when do the head and the brain grow the most
over the first 5 or 6 years and approach adult levels by age 10
how does the lymphoid system develop and what does it contain
it contains the thymus and lymph glands, develops rapidly early in life greatly exceeding adult dimensions by about age 12
what is puberty?
the developmental stage leading up to adolescence when glands associated with the reproductive system begin to enlarge, bringing about changes in physical appearance and behavior
what hormones does puberty increase in males and females?
in males - androgens, especially testosterone and in females - estrogen and progesterone
how long does puberty last
about 4 to 5 years
breast development + periods
initial breast development begins at about 11 years and is mostly complete by 15 or 16 + a girl’s first period typically occurs at about 13 years of age although many girls don’t become fertile until they’re about 15/16 because eggs aren’t always produced in the beginning
when does a growth spurt start in girls and when is skeletal growth complete
the growth spurt starts around the age of 12, skeletal growth is complete between 14 and 15
when
when do testes being to increase in size and when does the penis begin to increase
testes begin to increase between 11 and 12 and the penis increases beginning about 13
when do boys usually have their first nocturnal emission and when do they develop facial hair
first nocturnal emission - 14
facial hair - between the ages of 15 and 16
when does the male voice change begin and when does it end
begins at 13 and is complete by age 15
why has the average age of menarche decreased
better nutrition + girls who’re overweight get it sooner
what’s the average period age now int he US
for white girls it’s 12.6 and 12.1 for black girls
what’s the average age of breast development and presence of pubic hair
for breast development was 9.96 in white girls and 8.87 for African American girls, some girls showing signs of breast development as early as age 3
why does pubertal development start earlier now than it did in the past
exposure to passive tobacco smoke, insecticides, arsenic, polybrominated biphenyls (a fire retardant), chemicals used in common plastic, hormonal changes associated w obesity
habituation in babies
if a pattern is substituted for a new one, infants immediately increase their looking time
what do developmental psychologists use to assess infants’ abilities to perceive and remember
infant’s bias for looking at novel stimuli
when do infants start perceiving the difference between two checkerboards with different-sized squares and remembered that difference
when they were 1 day old
when do infants begin to show special interest in aspects of the environment that they can control
within a few weeks of birth
at which age did babies smile and attend much more to a mobile that moved in response to their own bodily movements
at 2 months
experiment with turning on an array of lights
4-month-olds learned to make a particular movement to turn on a small array of lights, lost interest when they got good at it + when conditions changed, got interested again
what happened when 4- and 5-month-old babies lost control of their ability to turn on a recording even though it kept playing
they showed anger and sadness
how do babies test objects’ properties
first 3 or 4 months of life by putting stuff in their mouths, by 5 or 6 months they start manipulating and exploring it
what is examining in babies
when they hold the object in front of their eyes, turn it side to side, pass it from one hand to another, rub it, squeeze it
does examining happen in all cultures + example
yes, !Kunga San people in Botswana don’t encourage it, but don’t stop it
gaze following
babies watch the eyes of a nearby person and move their own eyes to look at what that person is looking at
does gaze following always happen
no, when the adult’s eyes are closed or covered, the baby doesn’t look preferentially in the direction the adult is facing
what is the purpose of gaze following
ensures that the baby will attend to those objects and events that are of greatest interest to their elders, promotes language development (if the adult is naming an object, it’s useful to the child to know what object it is)
intentional agents
individuals who cause things to happen and whose behavior is designed to achieve some goal (around the latter part of the first year)
shared attention
a three-way interaction between the infant, another person, and an object - an adult points out objects that both the infant and adult see, by 12 months of age infants will point to it to alert others to the object they’re not attending to, between 12 and 18 months of age, they will point to direct an adult’s attention to an object the adult is search for
social referencing
babies look at their caregivers’ emotional expressions for clues about the possible danger of their own actions
examples of social referencing
12-month-olds didn’t crawl over a slight visual cliff if the mother showed a facial expression of fear but most did if the expression was of joy or interest + avoided a new toy if the mother showed a facial expression of disgust toward it
what are some core physical principles?
objects continue to exist even when they disappear from view, two solid objects can’t occupy the same space at the same time, if an object moves from one place to another, it must do so along a continuous path
who said that infants possess core knowledge about the physical world
spelke
according to spelke, what makes infants able to make sense of the physical world
skeletal competencies
violation of expectations experiment
in the habituation phase, the baby is shown a physical event until they’re bored with it
test phase - either an impossible event with mirrors or possible event
infants as young as 3.5 months looked longer at the impossible event
what is the proof that nuances of core knowledge are acquired w age
4-month-olds expected a box to fall to the ground when it was released in midair, but didn’t expect that when it was set on the edge of the shelf with most of its weight hanging off the shelf
only by 7 months believe that
object permanence
the principle that objects continue to exist when out of view (absent before the 5th month)
the simple hiding problem + who
Piaget, an attractive toy is shown to a baby and is placed under the napkin as the baby watches - younger than 5 months typically follow the toy with their eyes until it disappears
when can infants solve the simple hiding problem
between 6 and 9 months of age
changed hiding place problem (A not B problem)
the toy is first hidden under one napkin, then under another napkin - the baby reaches toward the first napkin
understanding of object permanence is still fragile, when pitted against a learned motor habit the habit wins
when can infants solve the A not B problem
by about 10 to 12 months
why are Piaget’s tests difficult for children
ability to plan the correct arm and hand movement to obtain a hidden object - the baby must know where the object is and be able to use that knowledge to guide movement
Piaget wrong???
researchers have found that infants as young as 3 to 4 months old who fail to reach for hidden object still look at the location where it’s hidden
Piaget wrong experiment???
8-month-olds tested in a series of search tasks - one group learned to crawl at least 9 weeks before the tests, a second group had 9 weeks of experience moving around in walkers, third group nothing
75% of the babies in the first two groups succeeded on the changed-hiding place problem, 13% in the third group
Piaget’s schemes
mental blueprints for actions, bodily movement or of something that a person can do with an object or category of objects
what are the earliest schemes
closely tied to specific objects, called forth only by immediate presence
