Chapter 10- Development 1 Flashcards
Researchers in human development are interested in studying age-related changes across the life span in three major domains
physical, cognitive, and social-emotional development
Research in human development seeks to answer three questions:
Is development a distinct, discontinuous process (is our growth punctuated by sharp and sudden changes in our abilities?) or is it a gradual, continuous process?
How doe nature (our genes) and nurture (our environment) interact to make us who we are?
To what extent do we stay the same over time (remain stable) versus change?
interactionist approach:
believing that development incorporates all of these ideas
Cross-sectional design
Individuals of different ages are studied at one point in time to find age-related differences
Advantage: Allows researchers to collect data quickly and inexpensively
Disadvantage: Cohort effects: Participants in each age group/cohort grew up in different historical contexts, can’t be certain if the differences between groups are due to age or the different social and political conditions experiences by each group
Ex: Studying differences in intellectual abilities of people who are 10, 30, 50, and 70.
Although 70 year olds may score lower on tests of intellectual ability than 30 year olds, may be due to differences in education, access to technology, or nutrition (not necessarily aging)
Longitudinal design
Same people are studied over time at various ages to find age related changes
Advantage: Allows researchers to look at real age-related changes because they are able to compare the same individuals at different ages
More sensitive to developmental influences than cross-sectional designs
Disadvantage: More costly and time consuming because it takes a number of years to complete
Selective attention/participant drop-out is an issue because over time people might lose interest or move away. May end up with a smaller and less representative sample
History effects: Can’t be sure whether changes in intellectual ability are due to aging and occur to everyone, or are unique to particular cohort
Longitudinal-sequential design
Combination of the cross-sectional and longitudinal designs
Two or more age groups of people are studied repeatedly over time
Allows researchers to repeatedly test two or more age cohorts as they grow older
Can compare different cohorts at the same age to see if they exhibit the same behaviours
Can determine if different cohorts follow a similar developmental pattern
Advantage: Very comprehensive
Disadvantage: Costly and time consuming
Prenatal development is divided into 3 distinct stages
the germinal, embryonic, and fetal stages.
Germinal Stage
Begins at conception, lasts for 2 weeks
Conception: fertilized egg is a single celled zygote
Zygote
the single cell that results when a sperm fertilizes an egg
Develops rapidly around 36 hours after conception
Blastocyst
The multi-celled organism developed by the 7th day
On 7th day, travels down the fallopian tube and attaches to the uterine wall
30-50% do not implant properly and the pregnancy ends without the woman knowing she was pregnant
2) Embryonic Stage
Occurs if implantation is successful
From 2-8 weeks after conception
Growing bundle of cells is an embryo
Marked by the formation of the major organs: the nervous system, heart, eyes, ears, arms, legs, teeth, palate, and external genitalia
3) Fetal Stage
8 weeks after conception
Formation of bone cells
Heartbeat can be detected between 8-12 weeks into development
Organs grow and mature while the fetus rapidly increases in size
Rate of new neural growth is 3 million neurons per minute at its peak
Central nervous system (brain and spinal cord)
takes the longest amount of time to develop
Begins developing in the third week after conception and continues to develop nearly the entire time in the womb
Most major abnormalities occur in the
in the early stages of development
Blue bar indicates when major abnormalities can occur. After that period, minor abnormalities can still occur
The ovum is fertilized
in the fallopian tube
As the zygote grow
it moves through the fallopian tube into the uterus, where it attaches to the uterine wall and implants there
The brain is the first major organ to develop and is still growing rapidly at birth
By time infant is born, its head has grown to 25% of its adult weight, whereas its body is only 5% of its adult weight
Neural migration
The movement of neurons from one part of the fetal brain to more permanent destinations
Occurs during the 3rd to 5th month of pregnancy/fetal stage
Prenatal exposure to toxins and viruses may interfere with normal neural migration and increase the risk of psychological disorders
Development Timeline
After nervous system starts to form, the embryo begins to move
4-6 months after conception, the fetus’s movements are noticeable
Mothers can feel the fetus moving as early as 16 weeks into pregnancy, although it might feel like abdominal gas or “butterflies”
Male fetus’s are more active than females, their greater activity levels after birth may be inborn
How Can Researchers Know What a Fetus Prefers?
Monitor the fetus’s heart rate
Slowed heart rate indicates attention, interest, or orienting response
Increased heart rate indicates fear or distress
Certain sounds and music that fetuses are exposed to change their neural networks, these sounds/music are retained in memory for at least four months after birth
Learning already occurs prior to birth
The major sensory systems develop at different times and rates.
Hearing
Ears are connected to auditory pathway 18 weeks after conception
Neurons connecting the ear to the brain are complete
Responds to sound 26 weeks after conception
Fetuses find their mother’s voice soothing, prefer the sound of their mother’s voice to others 6 months + few weeks after conception
Hearing almost adult like after birth
Smell and Taste
Taste and odour from mother’s diet are present in amniotic fluid
Sensitive to odours in the amniotic fluid before birth and remember those smells
When pregnant mothers consume anise flavoured foods during the end of their pregnancy, their newborns liked the smell of anise more than babies whose mothers did not consume anise
Taste buds of fetus look like adults 13 to 15 weeks after conception
Sweet taste preference exists in the womb
Premature babies prefer sweet flavours
Vision
Fetuses do not open their eyes
recall: vision perception occurs in the brain, the brain needs visual stimulation to develop the sense of sight
At birth infants are near sighted
Cannot see as well as adults until 6 months old
Prenatal Programming
The process by which events in the womb alter the development of physical and psychological health
Chemical substances mother consumes/exposed to may influence the development of the brain and body systems in fetus
Common factors are maternal nutrition and substances that can cause permanent damage, known as teratogens
Teratogens
substances that interfered with development and can cause birth defects
Known teratogens
viruses (rubella/measles, flu), alcohol, nicotine, prescription drugs (antidepresssants/Prozac/Zoloft), and radiation
Viruses
Major impact during early pregnancy, little effect towards end of pregnancy
If a pregnant women develops an infection (like the flu) during the 4th-6th month of pregnancy, the risk of schizophrenia increases for the child later in life
Alcohol
No safe level of alcohol consumption during pregnancy
Most serious effect is fetal alcohol spectrum disorder (FASD)
Fetal alcohol spectrum disorder (FASD)
Consequence of prenatal alcohol exposure
Causes damage to CNS, low birth weight, physical abnormalities in the face, head, heart, and joints, intellectual disability and behavioural problems
Described as a spectrum of disorders because the types/degrees can vary
In Canada, 9/1000 children born suffer from FASD, 3000 babies a year
leading cause of intellectual disability
Binge drinking increases the severity
Nicotine
Interferes with oxygen supply to the fetus
Can lead to premature and low birth weight babies
Increased risk of stillbirth
If pregnant women smoke, doubles the risk of the child developing bipolar
Caffeine
Studies yield mixed results
Link between heavy caffeine consumption (over 300mg/3 cups of coffee a day) and increased risk of miscarriage or delivering low weight baby
Don’t need to stop drinking coffee, but should avoid over indulging
Prescription Drugs
Antidepressants Zoloft and Prozac can cause respiratory problems, increased risk of premature birth, and short-lasting effects on motor development
Other studies suggest there are few risks to developing fetus
If possible, avoid these drugs prior to pregnancy
Folic acid + Vitamins
reduce the rates of abnormalities in the nervous system, which starts developing 19 days after conception
Malnourishment
Schizophrenia and antisocial personality disorder more likely to occur if mother is malnourished during pregnancy
Iron deficiency
Iron deficiency in diet and maternal stress predispose infant to anemia/low red blood cell count, which affects how well the body functions
Can lead to cognitive impairment, motor deficiencies, and poor emotional functioning
Pregnancy Sickness
“Morning sickness”
Built in toxin detector
Pregnant women develop aversions to certain foods, nausea, vomiting
Worst during first 3 months of pregnancy, when fetus’ major organs develop and embryo is most vulnerable to teratogens
Occurs most commonly to foods with moulds (cheese and mushrooms), and to bitter substances (coffee). Possibly because these foods can cause birth defects
epigenetics
study of how environment affects gene expression
One of the most important examples(maternal nutrition) of epigenetics
Diet is environment
Certain maternal diet can lead to obesity in offspring
