Psych 2AA3.

Perspectives on child development

1. Biological

2. Psychodynamic

3. Learning

4. Cognitive

5. Contextual

Biological Perspective

- Psychological dev is a consequence of biological maturation of body & controlled by DNA (nativism)

- environment does NOT play a factor in child dev

Psychodynamic perspective

- Sigmund Freud: focus on unconscious

- Erikson's psychosocial theory: dev is driven by resolving social challenges

Learning Perspective

- Children are blank slates are learning determines their outcome

- Skinner & Watson

- Behaviour explained by paired associations b/w stimuli & response

- Classical + operant conditioning

- Rewards & punishments

Cognitive Perspective

- how intellectual capacity / thinking develops

- Piaget (stages of cognitive dev)

- informational processing theories

Contexual Perspective

- Dynamic interaction b/w child & others

- Vygotsky's theory of dev (through social interactions)

Scientific Method

1. Observation

2. Form hypothesis

3. Test hypothesis

4, Gather data

5. Draw a conclusion (interpret data)

*requires critical thinking

Measuring children's behaviour

- Observations (naturalistic, structured (lab setting))

- Experiments (relationship b/w 2 variables)

How to measure the dependent variable in an experiment

- sampling a behaviour

- self-report (ask what they think)

- physiological measures (HR, cortisol, etc.)

Experimental Designs

- correlational (evaluate rel b/w 2 naturally existing variables)

- developmental designs (longitudinal & cross-sectional)

Longitudinal vs cross-sectional design

- Longitudinal: same people followed across time

- Cross-sectional: people of different ages viewed at the same time

longitudinal design advantages

- same individuals measured (variables consistent across measurements, addresses individual differences)

- expensive & time-consuming

longitudinal design disadvantages

- practice effect

- selective attrition

- cohort effects (ex: covid cohort)

cross-sectional study advantages

- saves time

- saves money

- most common in dev studies (efficient)

- if large enough sample, individual differences cancel out

cross-sectional study disadvantages

- cohort effect

- lack of continuity in sample

Longitudinal Sequential Design

- Begin with cross-sectional study, continue with same individuals longitudinally

- continuity across individuals, less prone to selective attrition & cohort effects

Ethological Theory (part of biological perspective)

views development from an evolutionary perspective (inherit adaptive behaviours and learning can occur but only at certain stages)

Critical period (part of ethnological theory)

Time when a specific type of learning can take place; before or after the critical period the same learning is difficult or even impossible

Erikson's Psychosocial Theory (definition)

development consists of a sequence of stages, each defined by a unique crisis or challenge

Erikson's Psychosocial Theory- birth to 1 year

Basic trust of caregiver or mistrust

-Child looks towards the primary caregiver for stability and consistency of care

Erikson's Psychosocial Theory - 1-3 years

Autonomy versus shame and self doubt

-children are focussed on developing a sense of personal control or physical skills and a sense of independence

Erikson's Psychosocial Theory- 3-6

Initiative versus guilt

-The child is regularly interacting with other children please provide children with the opportunity to explore their interpersonal skills through initiating activities

Erikson's Psychosocial Theory- 6-teens

Industry versus inferiority

-The child now feels the need to win approval by demonstrating specific competencies that are valued by society and begin to develop a sense of pride in their accomplishments

Erikson's Psychosocial Theory- Adolescence

Identity versus identity confusion

-Child searches for a sense of self and personality identity through an intense exploration A personal values beliefs and goals

Erikson's Psychosocial Theory- Young adulthood

Intimacy versus isolation

Erikson's Psychosocial Theory- middle adulthood

Generativity versus stagnation

Erikson's Psychosocial Theory- late life

Integrity versus despair

Operant conditioning-positive reinforcement

Reward good behaviour

Increases likelihood of reoccurrence

Operant conditioning - negative reinforcement

Taking away a negative when child starts engaging in good behaviour

Increases likelihood of reoccurrence

Operant conditioning - positive punishment

Negative consequence after undesired behaviour to decrease likelihood in future

Operant conditioning - negative punishment

Removing a desired stimulus after undesired behaviour to decrease likelihood in future

Observational learning (part of learning perspective)

Children can learn by watching people around them

Bandura's Bobo doll (observational learning)

Children observed an adult hitting a blowup doll

Only some children spontaneously imitated behaviour (more likely if the adult appeared to be smart and talented)

All children could repeat behaviours on command

self-efficacy (part of learning perspective)

Beliefs about on abilities and talents dictates how much children relate to others and imitate that behaviour

Cognitive developmental perspective

- Children's thinking changes as they grow

- Jean Piaget: children try to make sense of the world

- Create theories about physical and social world

- Revise their theories often and radically

Brofenbrenner's Ecological Systems Theory (definition)

Individuals in the middle and is directly and indirectly affected by many systems

Five systems: microsystem, mesosystem, Exosystem, macrosystem and Chronosystem

Microsystem (Bronfenbrenner)

People and objects in an individual's immediate environment (Family)

Mesosystem (Bronfenbrenner)

Microsystems affecting one another (school might affect neighborhood; neighbourhood might affect home)

Exosystem (Bronfenbrenner)

Social systems that a child might not experience firsthand (parents workplace)

Macrosystem (Bronfenbrenner)

Cultures and subcultures in which the other systems are embedded (culture of mothers coworker, cultures of students teacher)

Chronosystem (Bronfenbrenner)

Systems are always in flux within the microsystem (sister might leave for University, or mother has a new coworker)

Themes in child development

Continuity, nature versus nurture, the active child, links between domains of development

Continuous vs discontinuous development

Continuous: once a child starts on a certain trajectory, they stay on that path throughout life

Discontinuous: early behaviours and situations never predict later development

Active and passive child

Passive child: at mercy to their environment

Active child: actively influences their own development through their unique individual characteristics

Links between domains of development

Each domain have impacts on one another but not necessarily at the same time

Genes

- smallest unit of biochemical instructions found in DNA

- each chromosome consists of 1 DNA molecule

- less than 1% accounts for individual differences (99% same)

Genotype

genetic makeup (sum of all genes a person has)

Allele

Different versions of a gene

Phenotype

visible traits

Sickle cell anaemia

- from homozygous recessive alleles

- heterozygous phenotype: sickle-cell trait (carrier)

- Incomplete dominance: dominant alleles do not always dominate recessive alleles completely

Sickle cell trait

- Heterozygous for sickle cell anaemia

- Most asymptomatic

- Mild form of the disease with hypoxia

Down Syndrome (Trisomy 21)

- extra chromosome 21

- distinct facial features

- mental & motor delays

- Often from egg (mother)

- Likelihood of passing on extra chromosome 21 increases with mothers age (age 20: 1/1000, age 40: 1/50)

Evolutionary theory

- evolution

- natural selection

- heritability

Natural selection

environmental conditions allow some members of species to survive & pass on genes to future generations, while others do not, env selects hereditary traits that improve survival

Evolution

- process of change in gene frequencies over many generations

- does NOT act on individuals

- does NOT act on traits that are not hereditary (passed on gen-gen)

Polygenetic inheritance

- most traits determined by multiple genes (+ their interactions with env)

- leads to a normal distribution

Evolutionary theory in child development (behaviours that have changed across generations)

- selected traits may be maximally adaptive at each stage of dev

- Ex: infant's poor visual acuity (so there is no sensory overload)

Heritability

- proportion of variation among individuals that we can attribute to genes

- index 0-1 (0: none of the variance is due to genetics, 1: all variance is due to genetics)

- greater variability in env -> less heritability

When environment constant, but differences are observed, heritability is

high (genetics is driving the difference)

When environment changes, & differences are observed, heritability is

low (environment drives some of the difference)

How do genes & environment interact?

1. Developmental Systems Theory

2. Gene to Environment Theory

*complementary theories, describe different aspects of development

Developmental Systems Theory

- Development from reciprocal interactions b/w individual & their environment

- Interaction at 4 levels: environment, behaviour, neural activity, genetic activity

- genetics & environment interact through this mechanisms

Epigenetics

- functional change in genome that doesn't involve alteration in DNA sequence (i.e. gene expression)

- experience modifies chemistry of gene activity, leading to changes in behaviour

- ex: lizard exposed to snake has offspring with longer tails, larger, & more reactive

HG vs LG pups

HG: lower stress response, become HG moms

LG: higher stress response, become LG moms

HG & LG moms with adopted offspring

Same

HG: lower stress response, become HG moms

LG: higher stress response, become LG moms

Conclusion of HG/LG mice study

Environment > Genetics

Methylation

turns OFF gene expression

Methylation & stress response

- methylation: silences gene for creating receptors, poor stress regulation

- demethylation: allows receptor formation, better stress regulation

Environment -> Genetic activity in HG/LG mice study (effects of methylation on stress)

- birth: equal methylation in HG & LG pups

- day 6: demethylation of receptor-creating genes in HG pups only (better stress regulation)

HG/LG mice study + second variable (human handling)

- handling of pups (tactile stimulation) increases cortisol receptors & behaviourally increases frequency of maternal grooming

- LG handled pups had high receptor formation

- non-handled pups had lower receptor formation

Apply dynamic systems theory to HG/LG mice study

- Environment: presence of human handling

- Behaviour: being groomed by mom

- Neural: brain processes tactile (+ other) sensations

- Genetic: demethylation of genes

- Neural: more cortisol receptors

- Behaviour: better stress regulation, become HG moms

Gene to Environment Theory

- 3 types of genotype-environment effects: passive, evocative, active (not mutually exclusive)

Passive gene-environment effect

- genetically related parents provide rearing environment

- child's family shares genetically determined abilities and interests

- stronger earlier in life

Evocative gene-environment effect

- children's genotype causes them to act in a way that evokes certain responses from those around them

- child elicits response from others

- ex: smily baby, smile back, adults are happy people

Active gene-environment effect

- genotype influences types of environments the child selects

- stronger later in life

Breast-feeding & IQ

- breast fed babies had higher IQs as children, adolescents, & adults (FAs in human breast milk foster brain dev)

- BUT, alleles (C) on gene determined whether breast fed babies had higher IQ

- therefore, genetics matter!

- BUT, not enough to recommend one or the other

Conduct disorder

- children/adolescents who consistently break rules or violate others' rights

- more common in boys

- early onset (

Effect on environment - Conduct disorder

- higher maltreatment group had higher conduct disorder %

- therefore, environment matters

- BUT, not all maltreated children dev disorder, & not all with disorder were maltreated

- maltreatment significantly impacts dev in people with low MAOA gene (metabolizes NE, serotonin, dopamine)

- high MAOA mediates effects of maltreatment on later antisocial behaviour

- therefore, genetic disposition may impact environment

Steps of prenatal brain development

1. Formation of neural tube

2. Neurogenesis

3. Migration

4. Differentiation

5. Cell & synaptic pruning

prenatal brain development - formation of neural tube

- folding/closing of neural plate (becomes spinal cord)

- 18-24 days after conception

- location on plate determines what cell will become (peripheral vs central)

- failure to properly close causes birth defects (spina bifida)

prenatal brain development - neurogenesis

- neurons form in a region of neural tube

- occurs 10-28 weeks after conception

- at peak: 4000 neurons/s

- no neurons after birth (except in hippocampus)

prenatal brain development - migration

- neurons move to permanent location via glial cells

- by 7 months after conception

- faulty migration associated with neural disorders (epilepsy, cerebral palsy)

prenatal brain development - differentiation

- neurons become larger, form dendrites & axons

- specialize

- synaptogenesis begins

- myelination (inc conduction velocity, dec signal leakage)

When does myelination occur

some prenatally + early in infancy to adulthood

prenatal brain development - cell & synaptic pruning

- removal of neurons & synapses not being used

- to increase efficiency of brain

- use it or lose it

- continues into adulthood

prenatal hearing

- cannot hear words

- at 16 weeks gestation, fetus can perceive sound outside womb through fluid-filled ears

- no evidence to suggest reading to baby stimulates brain development

- prenatal experience is not necessary for auditory development

prenatal hearing - can moms encourage bilingualism?

- Moms may be able to encourage bilingualism

- Sounds shape brain dev & will predispose children to learn those languages

- familiarity

hearing development in children with deaf parents

- no evidence that hearing of deaf parents experience language delay

- after birth, 5-10 hours a week of exposure to spoken sounds is sufficient to dev normal hearing

- newborns of deaf have same preferences as newborns of hearing parents (infant-directed speech)

- prenatal experience is not necessary for auditory development

Prenatal hearing & familiarity study (Dr Seuss reading)

- mothers read Dr Seuss out loud while pregnant

- after birth, newborns controlled sucking to hear Dr Seuss more than other book

- preferred moms voice over a different voice (no pref for dads)

- fetus can only hear through amniotic fluid, likely only hears moms voice internally

Prenatal taste study with carrot juice

- women planning on breast-feeding assigned to: (1) 300mL carrot juice 3 weeks before birth, (2) 300mL water before birth & carrot juice after birth, or (3) 300mL water 3 weeks before birth

- when solid foods started (~6m), babies given cereal made of water or carrot juice

- results: babies with prenatal or after birth exposure to carrot juice showed less negative expressions with carrot cereal, enjoyed more, & no difference in control group

- also showed that infants memory can last as long as 6 months!

Direct observation prenatal taste study

- 4D scans of facial movements

- moms given: (1) carrot-flavour capsule, (2) kale-flavoured capsule (bitter), or (3) no capsule

- results: kale flavour showed unpleasant facial expressions, carrot flavour showed happy facial expressions

Sex linked genetic disorders

A mutation that occurs on the sex chromosomes

Klinefelter's syndrome (XXY)

- 1 in 500-1000 male births

- Tall, small testicles, sterile, below average intelligence, enlarged breasts, broad hips

Turner Syndrome (XO)

- 1 in 2500-5000 female births

- short, limited development of secondary sex characteristics, problems perceiving spatial relations

XXX Syndrome (Metafemale)

One in 500-1200 female births

Delayed motor and language development, average intelligence and regular growth

polygenic inheritance

Combined activity of many separate genes

Results in behavioural traits

Most all around average (follows a normal distribution)

Eg. intelligence

monozygotic twins

identical twins formed when one zygote splits into two

100% the same DNA

Dizygotic twins

Two separate eggs fertilized by two separate sperm, 50% same DNA

twin studies

Same environments, similar development

Compare which twins are more like:

If monozygotic twins are more like trait is likely inherited

adoption studies

Comparing child scores with biological and adoptive parents

Who is more similar