Biological and Motor Development Flashcards
Week 2 (34 cards)
How does genetics interact with psychology? What is an example of this interaction?
Natural variations:
* Physical
* Cognitive e.g. IQ, language, memory
* Behavioural e.g. personality
Psychology interfaces with genetics as:
* Genotype + environment = phenotype (how our genetics manifest)
* e.g. genetic predisposition to anxiety + environmental situation (e.g. scary interaction with spiders) = anxiety manifests as fear of spiders
What is the aim of behavioural genetics?
Behavioural genetics aims to determine contributions from nature and nurture to behavioural diversity
What is heritability?
portion of given behaviour due to genetics not environmental factors
How should heritability statistics be correctly interpreted? How does this show the mechanism of heritability?
Correct = 60% of variation in IQ in a given population is due to gene differences
* Therefore heritability speaks to the variation of a trait within a given sample not about the contribution of genetics and environment to a trait in the individual
* Due to seeing less variation in some environments as environment is optimised for everybody in regard to that trait
How does heritability influence development? Describe a study that shows this influence/interaction.
heritability interacts with environment
Haworth et al. (2009): heritability of IQ increases across development
* Young children: increased contribution of environment than genetics
* Adolescents: increased contribution of genetics than environment
* Why? We actively construct out environment -> phenotype–environment correlation
* Increasing control over experience as we age
What is niche-picking and how does it influence development?
sharing similar genetics may lead children to seek out similar environment
How is heritability influenced by environment? Describe a study that shows this interaction/influence.
environmental constraints
Twkeimer et al. (2003): heritability of IQ varies with SES
* Low SES: 60% of IQ due to shared environment as environment is optimised for IQ less environmental influence/variability
* High SES: opposite pattern, therefore more influence from genes in high SES as environment no optimised it has higher influence on gene expression
* Many environmental factors affect brain development and hence gene expression (epigentics) e.g. diet, early social interaction
What is the logic behind classic twin studies?
identical twins share more DNA than fraternal twins but both share same amount of environment
therefore, if identical is more similar on a given behaviour than fraternal then behaviour is said to have a heritable component
What is a criticism of classic twin studies?
Questioned as can we assume each type of twin shares the same environment and reasons to believe their identity alters environment
* People treat identical twins and expect them to behave more similarly than fraternal twins
* Manner of socialisation of each twin type likely to lead to similarities in behavioural outcomes
What test has replaced classic twin studies?
identical twins separated from birth
What is a limitation of the modern twin study design and how was this limitation resolved? Describe the study that implements this modern design.
Animal models in place of separated twins due to reduced number of cases
Epigenetic influences on rat parenting
* Fostered/adopted rat pups by either nurturing or neglectful mothers (rats)
Nurturing mothers
* Reduced stress reactivity in pups
* Due to gene expression (even though not genetically related to mother) -> genes in hippocampus relevant to developing stress regulation are switched on
Neglectful mothers
* Neglected pups turn into neglectful parents
* Genes relevant to female hormones and maternal behaviour in later life switched off
What is the scope of behavioural genetics?
- Studies looking into range of behaviours
- Not deterministic -> show potential collection of gene expressions leading to behavioural patterns
What are teratogens and how do they affect foetal development?
Teratogen: any kind of substance that can influence development (internal or external)
Effects:
* most affected in specific critical periods of development
Effects influenced by:
* critical period
* dosage and duration
* environmental factors
* genetics
What is the most famous example of a teratogen?
Thalidomide
* Widely used tranquiliser in Aus/UK
* Ok when tested on pregnant rats – not humans
* Use of drug and affect dependent on what stage of development it was used
What are the 3 priniciples of growth?
- Cephalocaudal principle: head to tail
- Proximodistal principle: from centre outwards
- Orthogenetic principle: global -> differentiated cells
What are some other examples of teratogens? (list 3)
Maternal diseases and disorders
* Rubella + birth defects
* HIV + AIDS
* Chronic infections e.g. syphilis
* High BP, diabetes etc.
* Rh incompatibility
* Emotional stress, nutrition, age, previous birth
Prescription and non-prescription drugs
* Foetal alcohol syndrome
Why is it important for babies to develop complex motor skills?
Important as successful achievement of motor skill milestones = typical perceptual and cognitive development
How do developmental disorders and motor skills interact?
Many developmental disorders often accompanied by motor difficulties:
* e.g. ADHD: deficits in gross motor skills (clumsiness)
* Motor problems = warning signs of future/current problems
* Impacts other areas -> clumsiness noticed by peers and may lead to bullying and social development issues
What are 2 reflexes present from birth?
Babinski: sole of foot stroked = toes fan out (8-12MO)
Palmar reflex: grabbing things placed in palm/hand
What is the developmental trajectory of motor ability? (4 stages) What is a key feature of each stage?
0-2YO, 2-6YO, Adolescence, Early adulthood
0-2YO
* Reflexes overlaid by voluntary rudimentary movements by 6MO
* Enable control of interactions with environment therefore providing further development opportunities
2-6years
* Develop basic movement chains or motor schemas (catch ball)
* Repeat motor schemas until they become automated
* Handedness established
Adolescence
* Dramatic body schema update
* Streamlining connections: frontal and multimodal association cortex due to Myelination -> faster transmission in brain
Early adulthood
* Muscles stronger and responses faster
* Peak ~30YO and downhill after
What did Gesell’s theory of motor development underestimate?
role of experience
Describe a study that highlighted Gesell’s underestimation of the role of experience.
not cross-cultural studies
Orphanage studies
Dennis (1960): Iranian orphanages
* Spent most of first 2 years on back
* Slowed walking development (15% 3-4YO could walk well)
* <50% could sit up on own
* Maturational proceses necessary but not sufficient for adequate psychomotor development
Romanian experience (1990s)
* No social contact/interaction so deprived in many ways
* Highlights importance of physical, sensory and cognitive stimulation for development
* Extreme effect on size of brain, much smaller for 3YO subject to neglect
What cross-cultural evidence is there that highlights the role of experience in motor development? What were the details of these studies?
Movement deprivation - sandbag nappies
* restricted movement for minimum 12 months
* Delayed in sitting alone, walking alone, declarative pointing (compared to control)
* Missed out on parental interaction and movement
* 3Yo still delayed and lower on non-verbal IQ
Movement stimulation
Hopkins (1991)
* UK and Jamaican mothers
* JM: followed traditional routines that nurtured motor development e.g. massaging infants & stretching limbs
* JM children showed advanced motor skills
Hamilton (1981): Arnhem Land
* Mothers prop up infants head (young as 8 weeks old) in sitting position, freeing hands for work and encourage early walking
* Advanced in raising head, sitting, standing, walking
Kearins (1986): Western Desert
* Aboriginals and Anglo Europeans
* Aboriginal mothers carry infants in up right position w/o head support
* Vs AE carry in horizontal position with head support
* Supported earlier head control and cascaded to support early achievement of other milestones
What does dynamic systems theory argue motor development is the outcome of? (3)
Maturation factors that interact with:
* Biomechanical properties of body
* Environmental support
* Task demands
