Lecture notes Lifespan development 3313 PDF

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Lifespan Development 3313 lecture notes Why study it? 1) To understand human behaviour through its changes across the lifespan 2) Helps us identify the best family and social systems needed to raise healthy and happy children 3) We can therefore counteract conditions that produce poorer outcomes Assumptions: 1) Studies of typical and atypical development are mutually informative - need to understand variability in typical development and what is atypical 2) Developmental change is influenced by a multitude of variables - within a child’s genetic and biological characteristics and ones that are external, like the physical environment 3) Development arises from a dynamic interplay between these variables: physiological, generic, social, cultural, cognitive and emotional…over time Development What: a sequence of changes over a lifespan Childhood: -

Changes are evident in almost every aspect of development (motor, moral, cognitive etc.) Typically, positive, but some exceptions

Across adulthood: -

Mirror image of childhood Decline, stability, or advance? o Argued that you peak at 25 but then declines o But other areas, such as vocabulary, tends to increase rather than decline

Aims: 1) Describe characteristics of psychological change over time a. Substantial differences in children in how they development  hard to determine what is typical i. Individual rates of development ii. What changes do we focus on? 2) Understand the mechanisms that underly these changes a. Theories provide these mechanisms/principles b. Theories aid in the selection of critical areas to study for this Key questions in child development: 1) How do nature and nurture shape development a. Nature: biological makeup b. Nurture: child’s environment and experiences (physical, cultural and social influences) i. There’s no simple answer to this, both contribute ii. Genes and environment both contribute to development often in interaction iii. Epigenetics: study of how the environment can influence the expression of genes 2) Do children shape their own development?

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a. Piaget’s constructivist position: children play a central role in their own development. They actively acquire knowledge through self-discovery in interaction with their environment i. Through exploration or practice skills b. Attentions is selective, and infants preferences tailor their early experiences Is development continuous or discontinuous? a. Stage theories: development is discontinuous – child’s thinking undergoes a qualitative change in moving from one stage to another b. Other theorists argue its continuous: its progressive without any major recognition What are the sources of changes and how do they occur? a. Proposed mechanisms: i. Basic learning ii. Development of information processing capacity iii. Development of effortful attention iv. Mechanisms specific to a developmental domain How does social and cultural context influence development?  to what extent is knowledge or capabilities universal rather than culturally specific? a. Interactions with immediate environment  family, friends, teachers b. Media c. Economical factors d. Cultural beliefs and values e. Childs historical context How do children develop so differently? a. Genetic differences b. In caregiver support and interaction c. Reactions to similar experiences d. Selecting environments that suit their interests and capabilities How can research promote children’s wellbeing? a. Provides information to parents (e.g. no alcohol when pregnant) b. Assist optimising education systems c. Guide intervention programs aimed at limiting atypical development Research methods used

Scientific method: an approach to testing beliefs that involves: 1) 2) 3) 4)

Choosing a question Form a hypothesis Testing it Draw conclusions a. All involve relationships between variables

Basic designs used: Naturalistic: investigate relationships between variables as they exist naturally -

Usually observational No interfering

Experimental: manipulate a variable of interest and examine its influence on an aspect of behaviour -

Children receive an experience of interest Control group doesn’t receive this but are matched to the experimental group IV: experimental vs control

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DV: behaviour hypothesised to be affected by the independent variable

Cross sectional: data collected from individuals varying in age at roughly the same point in time Longitudinal: same group tested repeatedly Micro genetic: - variant of longitudinal – intensive study of an area of change as it is happening Usually naturalistic, but can include experimental manipulations Longitudinal a) Prospective design: record behaviour working forwards in time (this year  2021  2023) b) Retrospective: work backwards in time (collect data from 2017  2018 -> this year) a. Prospective is generally better i. Can use a framework to collect data accurately ii. In retrospective designs we don’t have this control and therefore could affect result accuracy Advantages: -

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Permit the analysis of within individual change: o Stability or variability of behaviour over time o Onset and duration of critical behaviours o Different patterns of individual change Control for cohort differences (since using a single cohort) Can look at prediction of variables across time Prediction from time 1 to time 2 provides information on causality Cross lagged correlations consistent with A influencing development of B but not vice versa o E.g.

Disadvantages: -

Time consuming Cost Cohort effects Repeated use of same tests can be invalid Selective attrition may lead to biased principle

Cross sectional Advantages: -

Quick Cheap Avoids bias due to attrition No issue with repeated use of a test

Disadvantages:

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Difficult to establish a causal relationship Individual differences cannot be assessed Age effects confounded with cohort effects

Micro genetic method: a scientific method whereby the same setting is studied repeatedly to observe a change in detail 3 characteristics: 1) Observation period spans from beginning of the period of rapid change to stable use of target strategy a. In a critical period 2) High density of observations collected during this period a. Some studies look at children everyday and collect data daily 3) Intensive, trial by trial assessment of ongoing changes a. Qualitative and quantitative Advantages: -

Can reveal processes that underpin child changes Reveals variability in children’s thinking

Disadvantages: -

Doesn’t provide information about typical patterns of change over long periods Too time consuming to employ this method over several years

Variants on basic designs: Multiple cohort longitudinal design -

Test different ages at the same time and follow up on them Avoids weaknesses of cross sectional and longitudinal designs (except cost and time)

Experimental longitudinal study -

Involves an intervention with follow up surveys Assess groups at time 1 Intervention for group 1, control condition for group 2 Assess groups at time 2

Lecture (2) Nature vs Nurture Behaviour genetics: what you’re born with is how you turn out to be -

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Epigenetics: o Environmental factors that affect gene expression o Frequency, rate and factors that influence the expression Genotype: o Genetic material an individual inherits Phenotype o Observable expression of genotype o Physical appearance and behavioural tendencies Environment o Surroundings and experiences

Parents genotype – child’s genotype Basic genetics -

23 pairs of chromosomes – 2 determine sex Chromosomes are made up of 2 twisted strands of DNA Small segments of DNA are called genes Genes contain code for production of proteins Individual variability results from shuffling of chromosomes – 8 million variances Splitting of chromosomes may be different

Gene expression o Regulator genes control the activity of other genes o Additive heredity  Effects of certain genes add up to influence the phenotype o Dominant and recessive heredity  Dominant gene is more influential than recessive Additive expression o Alleles form the variability of the normal distribution – equal variances Basic dominant/recessive pattern X-linked dominance o X chromosome is longer than the y  some of the chromosomes on the x gene doesn’t have a matching y chromosome o X linked recessive genes affect phenotype of boys more than girls o Many diseases and disabilities are x linked Dominant/recessive patterns o Cystic fibrosis, Huntington’s X inked inheritance o Fragile x Chromosomal anomalies o Down syndrome Childs environment – child phenotype -

Any given genotype will develop differently in different environments This is the norm of reaction Phenylketonuria (PKU)  ability to process iron, o Normal diet  brain damage Parental contributions  environment that parents have for their child

Childs phenotype – child’s environment -

Children are active creators of the environment in which they live o Evoke certain responses from others o Select environments to match their own interests e.g. outgoing children may choose to do rock climbing, swimming etc  influenced by temperament which influences their environment o Choosing friends

Childs environment – child’s genotype -

Epigenetics

o Environment can influence silencing of genes o This is the process of methylation o Permanent effect on gene expression Behaviour genetics The aim of behaviour genetics is to estimate the relative influence of genetic and environmental influences Heritability: statistical estimate of the proportion of variance in a behaviour in a given population estimated to be due to genetic differences among those individuals -

For the population studied the heritability estimate refers to the variability in individuals studied E.g. 70% of the variability of the population is shy

Four sources of phenotypic variation 1. Genetic 2. Shared environment a. Common aspects that make children in the same family alike 3. Non -hared a. Environment specific effects that make children in the same family different to each other 4. Measurement error Designs used: 1. Adoption a. Whether the child is more like biological parents, it is a genetic effect b. If the child is more like scores of their adoptive family, it is an environmental influence 2. Twin study a. Compares correlations of identical twins to those of non-identical twins b. 100% of genes and 100% of environment c. 50% of genes, 100% of environment d. Gives us an index of the importance of genetic factors e. We compare the correlations of each pair to find this out f. Can be used to produce heritability estimate  looks at differences between correlations and puts it in a formula 3. Adoptive twin study design a. Mono twins – some reared together, some reared apart, these are then compared i. If MZA scores are lower, it suggests an environmental influence b. Dizygotic – compare reared together to reared apart Bouchard et al study: o IQ is strongly influencing by genetic factor o Higher in adulthood, than childhood o MZA twins are so similar because their identical genotypes make it likely that their effective environments are also very similar Ways that genetic endowment and environment interact: -

Parents adapt child’s environmental to suit child’s capabilities

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Niche picking – individual may seek environments, through play activities, employment, Reciprocal influences

4. Genome-wide complex trait analysis (GCTA) a. Analyse persons genetic material and group people together who have similar genetic makeups b. Look at how similar these are at tasks and compare them to others c. Used to examine expression of genes across different points in development d. Used to tease apart effects of genes and the environment

High heritability does not imply immutability (environment can’t influence outcome) -

Mean can increase but variability remains the same Heritability estimates don’t tell us anything about group differences Race differences in IQ are often mis-assumed that its due to genetics Heritability estimates can change according to the environment – socio cultural influences

Brain Development Issues with assuming brains are important for understanding development: 1. Brain changes are correlated with life changes 2. Matching brain changes to functional behaviour changes is no easy matter, the relationship is very complex Brains develop on:  

Size Synaptic properties Myelination Need to associate brain development with the development of function Likely that genes influence behaviour through their influence on (a) brain development and (b) the brains influence on cognitive functioning

Neurons: -

Neurons constitute the grey matter of the brain Send and receive electrochemical messages between brain and body At birth, brain contains 100 billion Glial cells (white matter) produce myelin sheath  coating on axon which insulates it and helps maintain the integrity of information transited

Neuronal development -

First few months there’s rapid growth in them, and refinement in axons and dendrites

Synaptogenesis -

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Process of exuberant generation of neuronal connections Dendrites are growing and hook up to other neurons in the brain Very rapid, forms millions of connections during this process Not efficient to have lots of connections, we must selectively pruning connections o Excess and unused synapses are gotten pruned  used ones are strengthened and maintained, it’s a competitive process Synaptic density varies as a function of age Process occurs at different times and different areas of the brain

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Reduction in synaptic density begins earlier in visual cortex than auditory or prefrontal cortex  could this maybe be the reason why children absorb information much faster?

Myelination: speeds up transmission of information across axon  affects speed of processing and could influence cognitive performance -

Rapid increase in myelination at around 40 weeks  if children are born preterm, does this affect myelination?

MRI techniques -

Can be used to see changes in white matter Sensory and motor areas of brain mature faster, frontal mature later and slower Could explain why adolescents engage in risky behaviour more

Experience and the brain -

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Experience expectant brain function o Brain functions that require certain basic common experiences to develop o Synapse’s that are activated are strengthened, those that are rarely activated are pruned o Without these experiences, development will be compromised o Brain is waiting for stimulation, if it doesn’t get it, it can lead to certain effects Experience dependant brain function o Brain functions that depend on, variable experiences and that therefore may or may not develop in an infant o Still developing, just a bit different

Frontal Lobe: -

Claim that frontal cortex is the cortical region that sets humans apart from other mammals o Development is slow and protracted over childhood o Prefrontal cortex is implicated in executive functioning o Pre-frontal regions and executive dysfunctions are implicated in several developmental disorders  Study did find that there’s not much difference between sizes of frontal lobes o humans and animals  Could be that human brains are more richly communicated and have more distinct patterns of firing  Greater connectivity due to more white matter  white matter appears important for brain development

Brain and size -

Rushton and Ankeny o Brain size correlated with cognitive ability o Big brain = higher IQ o Controversial o Differences in races do vary in brain sizes  suggests genetically inferior groups o Brain size is a red herring  why this is wrong (most likely)  Causal directions are ambiguous  Within groups differences in IQ is larger than between group differences  Within family correlations between brain size and cognitive ability are essentially zero

 No one knows what biological property of the brain is related to intelligence o Sex differences in IQ are very small relative to differences in brain size – something doesn’t add up? Brain and behaviour -

Relationship between biology and behaviour is complex o Identifying genetic basis doesn’t explain behaviour o Establishing that an area o characteristic of the brain is associated with a psychological trait doesn’t really explain behaviour o Environment also influences brain structure o Establishing cause is difficult

Lecture (3) Theories of Development Why: 1. Provide framework for understanding phenomenon a. Provide concepts we might not have considered 2. raise crucial questions about human nature 3. motivate new research, resulting in better understanding of children 4. predict behaviour (theories) Theory 1. Piaget Influences on his theory: 1. natural sciences  

Darwinism: species adapting to their environment Piaget – children assimilate and accommodate their environment

2. Philosophy   

Knowledge structure based on group structures of logic Logic is at the core of children’s cognitive development Logical-mathematical structures

3. Binet and the IQ test  

Qualitative changes in child’s cognitive development Young children think differently to older children

Driving development is: (1) nature (2) nurture (3) interactionist models Interactionist position: innate mechanisms and environment interact to influence development Interactionist, or known from Piaget as ‘constructivism’… -

Social interactions provide foundations for development There’s influences of innate reflexes and social environment through self-discovery recognizes influences of innate reflexes and social environment, but child essentially acquires knowledge through self-discovery in interaction with environment.

The Theory: -

4 stages of cognitive development

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Knowledge takes place in the form of schemas o Action schemas first then later internalised known as operations 2 processes driving development are adaptation and organisation

Organization: • •

combining actions or thoughts into new and more complex consistent and in balance with the environment e.g. realizing that one operation is the inverse of another.

structures that are internally

Adaptation: •

process of adjusting to the demands of the environment: •

assimilation - interpreting experiences using existing knowledge structures

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accommodation - modifying knowledge structures to incorporate or adapt to new experiences

Piaget’s Stages: •

Children’s cognition passes through 4 stages

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Perception and thinking changes fundamentally across these stages

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Key assumptions of stage theory: 1. Development is domain general, i.e. all areas of the child’s cognition are affected by the transition to a new stage 2. Stage invariance: All children pass through the stages in the same order (but can proceed at different rates)

STAGE

APPROX AGE

MAJOR FEATURE

sensorimotor

birth - 2 years

Experiences world through immediate sensory impressions & actions

preoperational

2-6 years

Can represent the world with words and images

concrete operational

7-12 years