Human Development Flashcards
What are the 4 mains issues concerned with describing developmental change?
Stability vs change
Continuity vs discontinuity
Nature and nurture
Critical and sensitive periods
What are the 2 main goals of Developmental Psychology?
1) to examine & describe the biological, physical, psychological and behavioural changes that occur as we age
2) ask what causes or drives these changes
Stability vs Change
Do our characteristics remain consistent as we age?
- how development occurs over the lifetime
- lots of change going on in the first years of life
- long periods of stability in adulthood (some change does happen here too)
Continuity vs discontinuity
What shape does development take?
Is it continuous - like how a plant grows?
Or is it discontinuous where we progress through qualitatively different stages - like a butterfly?
Nature and Nurture
To what extent is our development the product of:
Heredity (nature) and/or Environment (nurture)
How do the two interact? Eg the wild boy of Aveyron?
Critical and Sensitive Periods
Are some experiences especially important at particular ages?
Critical period - an age range during which certain experiences must occur for development to proceed normally or along a certain path
Sensitive period - an optimal age range for certain experiences BUT if those experiences occur at another time, normal development is possible.
Is the child active or passive in their development?
PASSIVE - Rousseau’s “noble savage” - the innocent infant who is helpless against the corruption of the insincere and evil society
ACTIVE - Transactional model argues that children will affect what happens to them just as much as they themselves are affected eg language
What are the ethics associated with studying children?
Freedom from harm
Informed consent
Vulnerable group?
Define naturalistic observation
When people are observed without interference
Conducted in natural rather than contrived situations
Case studies - advantages and disadvantages
-ve - results cannot be generalised to other situations or children
+ve - provide a large amount of rich detail
+ve - provide ideas about the developmental sequence of abilities to then generate hypotheses that can be examined with other methods
What is a cross-sectional design?
When subjects are studied at one point in time
What are the advantages of a cross-sectional design?
- less time consuming - lots of data can be collected quickly
- less expensive
- answers some questions clearly
- lessens the possibly of biased sampling
What are the disadvantages of a cross-sectional design?
- does not detect change within the individual, only the group
- cannot separate out the effects of age from the effects of the cohort
What is a longitudinal design?
When subjects are repeatedly tested at different ages over a period of time
What are the advantages of a longitudinal design?
- sensitive to intra-individual changes so essential for studying change in the individual
- everyone is exposed to the same historical time frame (all from the same cohort)
What are the disadvantages of a longitudinal design?
- time consuming
- expensive
- measures may become invalid before the research is complete
- participants may drop out - move away, drop out or die
- focus on just one cohort so the results may not be highly generalisable
- subject to biased sampling
What is a sequential design?
Combines both the cross-sectional and longitudinal approaches
What are the advantages and disadvantages of a sequential design?
Advantages - most comprehensive
Disadvantages:
- costliest
- most time consuming
- loses information about the individuals by examining the development of groups
Describe previous thinking on how much babies could do
- focus on sensorimotor experiences
- limited cognitive ability
- impressions are fragmented and confused
- very basic functions
Describe more recent thinking on how much babies can do
- infant experience is rich and coherent
- learning can occur even during the neonatal period
- can respond to mothers voice and music whilst inside the womb which can be seen when the baby is born
Nature in early development
DNA - strings of biochemical material that provide the code for genes (sets down the blueprint for who we are)
Influences the way in which all body & brain cells grow as well as function
Timetable and direction of prenatal growth is controlled by activation of correct genes at correct times
Nurture in early development
Physical impact - nutritional stimulation
- is the mother eating a sufficient diet?
Perceptual and Cognitive impact - sensory stimulation
- baby hears the music the mother can hear, feel the emotions the mother is feeling
Define genotype and phenotype
Genotype = total genetic endowment inherited by the individual
(the basic genetic blueprint)
Phenotype
- observable and measurable characteristics & traits of the individual
- product of the interaction of the genotype with the environment
Explain the impact of the environment on genes
Can modify, add to or inhibit the action of genes
- most cognitions & behaviours are a consequence of many genes (polygenic) and complex gene-environment interactions
Give an example of a gene/environment interaction
PKU (Phenylketonuria)
- a rare genetic condition
- baby is born without the ability to process protein
- if untreated, severe mental retardation occurs
- it is a treatable disease though
- need to follow a strict diet which is extremely low in phenylalanine particularly when the child is growing
Why do we need to know about the structure of chromosomes?
Because if something goes wrong with development, this is where it happens and we can investigate it
Describe Mitosis
- process by which new cells are made
- cells start to swell & duplicate all it’s chromosome pairs until there is the equivalent to two cells in one
- this cell then splits in half to make two new cells, each containing 23 pairs of chromosomes
What are operator genes?
Genes which activate growth and control builder structural genes
What are structural/builder genes?
Genes which code for a product/do the work
Describe how inactive genes can be activated by environmental events
Diamond (2009)
Diamond
- maternal stress prior to the conception of offspring can alter genes in the maternal ova
- this altered genome can be passed down to offspring
- stress before pregnancy can affect the child’s development in later life
Describe how genes can alter the effects of the environment
Caspi & Moffat (2006)
- people with a particular version of a gene involved in making serotonin are more likely to develop depression after a stressful life event than those with a different allele of this gene
- abused children are more likely to develop antisocial personality traits is they have a particular version of a neurotransmitter gene
- eg after a divorce someone can become more depressed if they have a gene that makes them susceptible for developing depression
Describe the Human Genome Project goals
- identify all the genes in human DNA
- determine the different sequences of the different chemical base pairs that make up human DNA
- store this information in databases
- improve tools for data analysis
- transfer related technologies to the private sector
- address the ethical, legal and social issues that may arise form the project
Describe the potential benefits for the Human Genome Project
- improved diagnosis of diseases - stop them or treat them better
- earlier detection of genetic dispositions to disease - eg pregnancy planning?
- assess health damage and risks caused by radiation exposure, including low-does exposure
- exonerate persons wrongly accused of crimes
- estvalish parernity and other family relationships
Issues with the Human Genome Project
Who would get the personal information about your genes?
Who decides what is a disease or a disorder?
Who owns all this information of the different sequences etc?
Who can get access to this information?
Congenital abnormalities and examples
- 7% of infants are born with one
- evident at birth but may or may nor be observed until childhood or adulthood - can be presents and everything seems fine but something will become apparent later on in childhood
- can be caused be a problem with the genes and/or chromosomes
- Huntington’s disease & Cystic Fibrosis
Describe chromosomal abnormalities
- sometimes the distribution of the 46 chromosomes is uneven
- this means the gamete has too few or too many chromosomes
- most of these abnormalities are lethal causing a miscarriage
- but not all, Trisomy 21 (Down’s Syndrome)
- caused by the inheritance of an extra 21st chromosome
- have lowered IQ, congenital eye, ear & heart defects as well as a number of distinctive physical features
What are the causes of chromosomal abnormalities?
Most common - the uneven segregation of chromosomes
Likelihood of this happening increases with the age of the mother
Ageing Ova Hypothesis - at 35 years, the ova begins to degenerate and produce abnormalities
- subject to more testing as you are more susceptible to abnormalities
Describe Genetic Abnormalities
- when there is a mutation in the structure of one or more genes
- can happen spontaneously or can be caused by environmental factors such as radiation, drug abuse, disease etc
- parents can be carriers of hereditary gene defects as recessive traits
- the problem only occurs if both parents have the harmful version of the gene and if the parents both pass on the harmful gene to the child
Example - Muscular Dystrophy and Haemophilia
What are the three stages of pre-natal development?
1) Germinal Period (weeks 1-2)
2) Embryonic Period (week 3-8)
3) Foetal Period (week 8 to birth)
Describe the Germinal Period
- sperm fertilises the female egg (ovum)
- forms a zygote which then repeatedly goes through cell division to become a mass of cells that attaches to the mother’s uterus about 10 to 14 days after conception
- the blastocyst also begins to secrete hormones that inhibit menstruation (indicates that the woman is pregnant)
Describe the Embryonic Period
- cell mass is now called an embryo which develops from the end of week 2 to week 8
- the placenta and umbilical cord develop at the start of this stage so since the cells are provided with nutrients & O2, the cells rapidly divide and become specialised
- all major biological organs & systems are formed
- week 8 - heart is beating, brain is forming and facial features such as the eyes can be recognised
- this is the most sensitive period to disruption (including miscarriage) due the vast amount of vast things happening
- if anything does go wrong, it can easily affect development
Describe the Foetal Period
- foetus develops from week 9 until birth
- muscles strengthen and other bodily systems develop
- many organs & structures are already formed so main focus is on growth and detailed development
- by 12 weeks the foetus can also suck, breathe and swallow
- at about 24 weeks, the eyes open
- around 27 weeks, the foetus attains the age of viability
(it is likely to survive outside the womb in case of a premature birth)
Describe the development of the brain and the nervous system
- the most dramatic development of any organ in the body
- the only organ in the body that develops throughout the prenatal period
- at birth - weighs about 25% of its eventual adult weight
- 6 months - weighs about 50% of its eventual adult weight
- first brain areas that mature are deep within the brain & regulate basic survival functions such as heartbeat and breathing
- rapid brain growth slows in later childhood - at 5 years, the brain has reached 90% of their adult size but brain maturation continues
- neurons become more insulated, unnecessary synapses are pruned back and lost, association areas of the cortex mature and the cerebral hemispheres become more highly specialised.