psych 1xx3

development

changes and continuities that happen within the individual between conception and death

• how you change overtime, but also how you stay the same

maturation

biologically timed changes within the person according to that persons genetic plan, influenced by environment, but timeline is largely biological.

learning

• Acquire new skills, information by experience (Enduring changes in thoughts, feelings, behaviour)

  • Permanent information storage through neural connections

Overcoming old learning

Sometimes learning means unlearning old habits.

Example:

Driving in Canada → move to UK → must override automatic “right side of road” behaviour.

Environment affects BOTH maturation & learning

• Poor nutrition → delayed puberty

• Rich language environment → faster vocabulary growth

interactionist perspective

emphasize that most of your developmental changes reflect the interaction of maturation + learning

• Please a key role and understanding inherited traits, prenatal development, and how nervous system develops across the lifespan

how maturation affects learning

certain biological systems must mature before learning is possible

eg.) trying to teach a four month old to walk won’t work because they’re not physically mature enough to learn the task.

how learning affects maturation

environmental input is necessary for normal maturation

• maturation may be delayed or absent without environmental stimulation.

• eg.) child with adequate nutrition, but raised in isolation (delayed speech, poor vision)

extreme behaviourist perspective

development completely environment dependent

• Watson: full manipulation of individual via nurture

naturist perspective

development completely dependent on genetics

Why developmental research is hard

• Many things change at once

• Impossible to control everything

• Lab findings don’t always transfer to real life

Why focus on infants & children?

• Most rapid & important changes happen early

• Easier to see developmental patterns

• eg.). changes from birth to age 5 are more greater than changes from 40 to 45.

limits of behavioural inference

Researchers infer cognition from behavior, which can be misleading

eg. measuring escape by speed, participant has broken leg. Slow escape does not equal lack of fear.

Competence vs Performance

Competence: What a child can do

Performance: What a child shows in a task

A child may have the ability but fail the task due to:

• Attention

• Language limits

• Motor control

An infant understands quantity but can’t point → performance underestimates competence.

habituation procedure

test weather infants can detect differences between stimuli

1. present same stimulus repeatedly

2. Measure response, physiological, or behavioural

3. Response decrease - habituation

4. Present a new stimulus

5. response increases - dishabituation

habituation

decrease in the responsiveness to a stimulus following its repeated presentation

dishabituation

increase in the responsiveness to a stimulus that somehow different from the habituated stimulus

event related potentials (ERP)

Measure brain electrical activity in response to stimuli, neuron populations

• Electrode-array cap on infant scalp detects electrical activity changes in neuron groups

  • Tells us what brain areas respond

  • provide neural evidence to complement behaviour

visual stimulus

occipital lobe activity

auditory stimulus

temporal lobe activity

High amplitude sucking method

measures preference (single stimulus) using sucking rate

• Special pacifier measures sucking rate

• Establish basal sucking activity, stimuli absent

• Shaping procedure: Infant controls stimuli presentation by sucking rate

  • Infant likes stimuli, increase sucking, pacifier maintains presentation

  • Infant dislikes stimuli, maintain or decrease sucking, pacifier ends presentation

preference method

• Examine multiple stimuli infant likes/dislikes by relative attention (measures preference based on looking time)

  • Not necessarily visual stimuli

  • Infant placed in looking chamber to measure gaze direction

  • Only used after confirming infants can discriminate stimuli

    • Avoid false (+)/(-): no preference vs cannot distinguish stimuli

developmental research studies

focusses on how abilities change across the lifespan not just that one moment.

longitudinal design

same people are studied repeatedly over some subset of their lifespan.

eg. testing same ppl memory every yr from 5-45

advantages: tracks individual development reveals long term patterns

disadvantages: time consuming practice effects, selective attrition

selective attrition

when some people are more likely to drop out of a study than others making samples non-representative of the original population

cross-sectional design

individuals from different age gaps are studied at the same point in time

eg. comparing memory in 25,30 and 50-year-olds.

advantages: fast inexpensive, no practice effects

disadvantages: Cannot verify if differences due to development changes vs generational differences (cohort effect), Not directly measuring changes with age, indirect inference from group data

cohort effect

A disadvantage of the cross-sectional design. Difference between age groups may be due to generational differences and not reflect actual differences in development.

Quasi-experimental method:

• Group subjects based on existing IV

  • Cannot manipulate IV {age, sex}

  • Cannot control variation → cannot establish causation

normative question

Investigates how things normally change as an individual ages. (description.)

how behaviour changes by age

analytic question.

Research focused on the processes and variables that are responsible for the changes in abilities and needs from age to age. (mechanism.)

why behaviour changes by age?

• Marshmallow study:

• 1 marshmallow immediately or 2 marshmallows 15:00 later

  • Self-regulation: Delay immediate gratification, requires development

    • Low restraint: drug use, divorce, BMI

    • High restraint: SAT scores, working memory

  • Test administered age 04, follow-up exam age 40

• Innate face preference study:

• Infants just born prefer looking at face-like (inverted) triangle dot arrangement vs upright triangle dot arrangement

  • Researcher travels to hospital after mother calls during labour

  • Researcher unaware of which pinhole box infant looks through (blinded)

  • Evidence of genetic influence of face preference

• Head start funded breakfast program study:

• Hungry students without breakfast have poor academic performance, nutritious breakfast improves academic performance, graduation rate, adult health (controlling for siblings)

zygote

• Cell formed during conception, sperm penetrates ovum

• 46 chromosomes 23 per parent

• zygote divides exponentially maintaining chromosome number

human genome project

• estimates [30000, 40000] genes

• SRY

• Sex-determining region Y protein (SRY) gene on 23rd chromosome

• X chromosome larger, more genetic information → more X-linked traits/disorders

  • Males have single X-chromosome → X-linked disorders more common in males

• Androgen insensitivity syndrome:

• Biological males resistant to androgens (male sex hormone causing male sexual characteristics)

  • Female physical characteristics

  • Male reproductive organ

  • Suggests gender is continuous

• Monozygotic (MZ) (identical) twins:

• Genetically identical

  • Same sperm-ovum creates 1x zygote → splits into 2x zygotes

• Dizygotic (DZ) (fraternal) twins:

• Genetically similar as siblings

  • Different sperm-ovum pairs create 2x zygotes

• Twin studies

• determine relative genes/environment influence on traits

  • MZ twins more similar than dizygotic twins (raised together): Genetic differences

  • DZ twins raised together: Genetic differences

  • MZ twins raised separately: Environmental differences

• Simple dominant-recessive:

• 2-allele combination determine simple trait expression

• Homozygous:

• Same alleles, same effect on expression

Heterozygous:

• Dominant allele expressed, recessive allele masked

• Ex. hair type, eye colour (visual traits)

Polygenic inheritance:

• Multiple alleles determine complex trait expression

  • More complex traits than simple dominant-recessive

  • Ex. height, weight (physical traits)

• Codominance:

• 2-allele combination equally expressed

  • Ex. ABO blood types

• Sex-linked inheritance:

• Alleles on X/Y chromosomes

Ex. X: colour blindness, Y: nonobstructive spermatogenic failure (no spermatogenesis → no sperm in semen, != physical obstruction)

• Canalization principle:

• Genotype restricts phenotype to limited outcomes

  • All species members share certain phenotypic traits independent of environment

• Range of reaction principle:

• Experiences (learning), environment produce phenotype range

Passive correlation:

• Parents raise child in environment complementing common genetic traits

  • More significant in infancy, early childhood

Active correlation:

• Individual actively seeks environment to complement traits

  • More significant in late childhood, adulthood

Evocative correlation:

• Genes influence social environment, how others behave towards individual

  • Consistent throughout lifespan

Critical period:

Developmental timeframe where specific environmental stimuli necessary to develop specific abilities

• Same environmental stimuli null after critical period

• Stimuli deprivation outside of critical period insignificant

• Ex. Kittens require visual input between 4-6 weeks to discriminate visual inputs

• Sensitive period:

• Developmental timeframe where learning most easily occurs, learning possible but more difficult outside timeframe

  • Brain maintains residual growth capacity into adulthood

  • More flexibility in when stimulation required, less specificity in type of stimulation required

  • Timeframe not explicit

Synaptic pruning:

Changes in neural structures that results in a reduction in the number of synapses.

Critical/sensitive period extreme approach social implications:

Extreme interpretations caused harm

• Overstimulating infants

• Refusing adoption of children >3

• Panic about “missed windows”

What research ACTUALLY shows

More stimulation ≠ smarter

• Brain doesn’t grow infinitely

• Excess stimulation → stress, withdrawal

✅ Less stimulation is harmful

• Deprivation → fewer synapses

• Poor cognitive outcomes

• Enriched environment:

• More stimuli != more neural connections

• Less stimulation inhibits brain development

Deprived environment:

Less stimuli → less neural connections

Natural environment

• minimal input may suffice for normal development

  • Enriched laboratory environments = normal natural environment

  • Standard laboratory environments = poor natural environment

Biological exuberance:

• Abundant synaptic connections in newborn infant's brain pruned with refined input as individual ages

• Mozart effect:

• False notion listening to classical music increases infant IQ

  • Participants = university students, original study independent of children

  • Small, temporary (15:00) performance increase on 1x spatial reasoning test

• Self-help books, media misinterpretations

• Misguided practical applications

• Misguided government policy

• Ocular dominance columns:

• Visual cortex structures formed by receiving visual input in corresponding eye

Columns of neurons in the visual cortex that respond preferentially to information from one eye or the other.

• Cataract:

Cloudy area in eye lens causing blurred vision

• Vision deprivation from one eye → ↓ corresponding ocular dominance column size

• Remove cataract early, cover healthy eye to decrease competition for visual cortex space

Ambylopia ("lazy eye"):

• Poor visual acuity after cataract removal, visual input not received during sensitive period

  • Improve visual acuity with practicing visual tasks (experience-dependent brain growth)

• Depriving sensory stimulation for one sense causes extra connections with other senses

  • Experience-dependent development

human development patterns

• Humans born with excess synapses pruned through development

  • Pruning mostly stops at adult maturity

• Unclear relation between synaptic growth, intelligence

• Brain synapses malleable at all ages

  • Learn new skills later in life

• Experience-expectant brain growth:

• Brain evolved to expect specific amount of environmental input (programmed development)

  • Normal development requires environmental stimulation

Experience-dependent brain growth:

• Brain development dependent on personal experiences (additional development beyond biological programming)

  • Plastic brain beyond normal development

Neural plate:

A key developmental component of the nervous system. It is composed of primitive neural tissue and eventually develops into the neural tube.

Neural tube:

The neural plate folds and closes to become a hollow structure known as the neural tube.

Plasticity

While the brain is most malleable in childhood, some brain plasticity is maintained in adulthood.

This plasticity helps us adapt to change in our environment or sensory abilities.

prenatal

The nervous system starts developing about 21 days (~3 weeks) after conception with the formation of primitive tissue known as the neural plate. The neural plate folds and closes to become the neural tube, which eventually leads to the development of the brain and spinal cord. The neural tube is lined with the neural stem cells that give rise to all cells of the nervous system. The basic human brain regions of the forebrain, midbrain, and hindbrain are visible after about 28 days. Although the brain begins to look distinctly human by 100 days after conception, it is only after about 210 days (~7 months) that it forms the sulci and gyri characteristic of the adult mammalian brain.

• Infancy, Childhood:

• Understand object permanence, detect numerical change

  • First few months: synapse increase

  • 1-10 years: synaptic pruning

  • <3 years: Overabundant synapses

    • Experience sensory information in undifferentiated manner

      • Auditory, visual cortexes activated to spoken language

Adolescence:

• Shift from self-focus to abstract reasoning

  • Substantial synaptic production, pruning (similar to infancy)

  • The greatest changes seem to occur in the frontal lobes, which are implicated in self-control, judgment, emotions, and planning

Adulthood:

Variable memory, intelligence decline compensated by vocabulary

• Neurogenesis is now thought to occur continuously in the hippocampus and the olfactory bulbs, suggesting neurogenesis may play a role in learning and memory

Fluid intelligence

• (cognitive processing speed, efficacy) ↓ α age

Generally involves abstract thinking and quick reasoning and tends to decline with age.

Crystallized intelligence

• (accumulated knowledge) =↑ α age

An individual’s accumulated knowledge. May increase with age.

Working memory, episodic memory

• ↓ with age {nonsense syllable recall}

Implicit memory

• ↑ with age {meaningful information recall}

• Perceptual narrowing to phoneme sensitivity:

• Phoneme discrimination potential narrows after 1 year

  • McGurk effect: eyes open = "da da", eyes closed = "ba ba"

    • True sound = "ga ga", brain rationalizes intermediate between mouth, sound

Neurogenesis:

The development and growth of neurons.

evolution

change in gene frequencies over generations

evolutionary psych

psych with attention to modern evolution knowledge and theory

• Evolutionary biology subfield

• Examine mechanisms of how biology influences psychology

• Evolution occurring through generations inferrential (cannot be empirically observed)

• Mental processes difficult to identify

• Infer adaptation from output, hypothesize behaviour under certain conditions to experiment

Additive microevolution:

Cumulative small changes → large evolutionary change

Adaptation:

• Physiological/psychological trait helping individual survive, increase reproductive fitness in habitat

  • Caused by gene-environment interactions

  • Higher mental processes: selective attention, memory encoding, retrieval

  • Not necessarily understand adaptation's past function

  • Not necessarily advantageous in modern environment

  • Not necessarily perfect, only function better

Fitness:

Reproductive success (copies of genes in next generation)

Darwinian fitness:

Genotype's average reproductive success compared to alternatives

Evolutionary pressure:

Environmental condition determining favoured traits

Species-typical behaviour:

Adaptive behaviour characteristic of species

Behavioural genetics study:

• Breed animal in captivity to artificially select trait

  • Ex. Drosophila melanogaster: fruit fly, most popular genetic testing animal for quick reproduction

Phylogeny:

• a pattern of evolutionary development and divergence of distinct lineage from common ancestors

Phylogenic trees

• constructed on developmental similarities:

  • Embryo anatomy

  • DNA (incl. non-transcribed regions)

selectionsim

• Traits → ↑ fitness, relative reproduction

Ex. Human Leukocyte Antigen (HLA)/Major Histocompatibility Complex (MHC): Genes with immune function, determine mammal body odours Females smelled T-shirts men slept in for 2x nights

• Naturally cycling prefer genetically dissimilar odours

• Oral hormonal contraceptives prefer genetically similar odours

• Ex. Phototactic behaviour (Daphnia magna): Swim to deep water during sunlight to avoid fish predators, return to shallow water at night to feed

  • Phototaxis more common when fish predator chemicals in water

  • Evolution α predation risk

    • No predators: Maladaptive function → phototactic behaviour genes less common

    • Predators: Adaptive function → phototactic behaviour genes more common

• Ex. Humans estimate greater vertical distance at high vantage point, no impact on estimating horizontal distance

Prisoner's Dilemma:

Optimal decision favours self

• a priori prediction:

• Make prediction from theory with testable hypothesis before data collection

post-hoc explanation:

Intuitive explanation after data collection

Ex. Adoption-conception phenomena: Adoption != fertility

• Post-adoption conception memorable {availability bias, confirmation bias}

• Ex. Finding reasons to rank novel face most attractive

• Moralistic fallacy:

• what should be morally correct → what is natural

• Naturalistic fallacy:

• what is natural → what should be morally correct

• Social Darwinism:

• Individuals with strong traits survive, weak traits weeded out

  • Traits not necessarily based on single heritable genes

• Eugenics:

• the science of trying to improve the human population by controlled breeding to increase desirable heritable traits

  • Cannot identify absolutely desirable traits

  • Human rights violations

• Mutation:

• New gene variants, may shift gene frequencies

• Genetic drift:

• Stochastic gene frequency change

• Migration:

• Population movement to new environment