Developmental Psychology Ch 1–2: Theories, Research & Genetics

[Ch 1] Developmental science: definition and two goals

The field studying children's physical, intellectual, social and emotional development. Goals: understand the biological and cultural processes behind development, and devise ways to safeguard children's health and well-being.

[Ch 1] Five periods of development with ages

Prenatal (conception to birth); infancy (0 to 2); early childhood (2 to 6); middle childhood (6 to 12); adolescence (12 to 18). Boundaries are guides, not strict.

[Ch 1] Three domains (processes) of development

Biological (height, weight, motor skills); cognitive (thought, intelligence, language); socio-emotional (relationships, emotions, personality).

[Ch 1] Three features of developmental change

Orderly (logical sequence), cumulative (includes all that came before), directional (increases in complexity).

[Ch 1] Development vs growth

Development is qualitative (type or kind) and quantitative (amount). Growth is only quantitative (size).

[Ch 1] Critical period vs sensitive period

Critical: the feature must emerge during that time. Sensitive: optimal time, an experience has an especially profound effect, but it is not essential.

[Ch 1] Active vs passive theories

Active: children make sense of the world and direct their own learning. Passive: the environment stimulates a child who only reacts.

[Ch 1] Preformationism

The belief that adult-like capacities, desires, interests and emotions are present in early childhood.

[Ch 1] How did views of children change over history?

Medieval: miniature adults. Protestant Reformation: willful, sinful, needing harsh treatment. Industrialization: protectionist view and the rise of developmental science.

[Ch 1] Darwin's and Preyer's contributions

Darwin: theory of evolution, scientific method for studying development. Preyer: first child development textbook, sequences of behaviour (walking from crawling), rules of observation.

[Ch 1] Freud vs Erikson

Both psychodynamic. Freud: psychosexual stages tied to the sex drive. Erikson: psychosocial stages, tasks or crises shaped by social and cultural factors.

[Ch 1] Watson, Thorndike, Skinner

Behaviourists. Watson: classical conditioning (association). Thorndike: law of effect. Skinner: operant conditioning (reward and punishment).

[Ch 1] Law of effect

Thorndike: behaviours with a satisfying effect are likely to be repeated; uncomfortable effects make a behaviour less likely.

[Ch 1] Bandura's theory

Social learning (social cognitive) theory: learning by observing and interacting with others.

[Ch 1] Piaget's theory in one line

Constructivist: children actively construct reality through schemas, searching for a fit between schemas and experience (equilibration), moving through universal stages.

[Ch 1] Vygotsky and the ZPD

Sociocultural theory: culture shapes development. Zone of proximal development: the gap between what a child can do alone and with a more competent person.

[Ch 1] Ethology

The science of the biological and evolutionary foundations of behaviour. Basis of evolutionary theories (and Bowlby's attachment theory).

[Ch 1] Information-processing theories

Use a computer analogy: how children perceive, store, organize, retrieve and manipulate information more efficiently with age.

[Ch 1] Dynamic systems vs ecological systems theory

Dynamic (Thelen and Smith): new behaviour systems emerge from interaction of simpler parts. Ecological (Bronfenbrenner): organization of environmental contexts around the child.

[Ch 1] Bronfenbrenner's five systems

Micro (face-to-face settings), meso (links between them), exo (settings affecting the child that exclude the child, e.g. parent's workplace), macro (culture's values and laws), chrono (timing and historical time).

[Ch 1] Four central issues of developmental science

Sources of development; plasticity; continuity/discontinuity; individual differences.

[Ch 1] Plasticity

How open development is to change and intervention. Greatest during sensitive periods.

[Ch 1] Continuity vs discontinuity

Continuity: gradual accumulation of small changes. Discontinuity: abrupt change and stages. Walking built from crawling and standing is continuity.

[Ch 1] Basic, applied and action research

Basic: advance scientific knowledge. Applied: solve practical problems. Action: provide data for social policy decisions.

[Ch 1] Four criteria for judging research

Objectivity (no distortion by preconceptions), reliability (consistent measurements), replicability (same procedures, same results), validity (measures what it intends).

[Ch 1] Four steps of the scientific method

Choose a question, formulate a testable hypothesis, develop a method, use the data to draw a conclusion.

[Ch 1] Naturalistic observation: pros and cons

Pro: objective, shows full complexity. Con: people may act differently when watched; time-consuming to analyze.

[Ch 1] Experiment: pros and cons

Pro: best test of causal hypotheses. Con: people may behave differently in the setting, hurting validity. Uses experimental and control groups.

[Ch 1] Clinical interview vs structured interview

Clinical: questions tailored to each answer; poor for very young children. Structured: everyone gets the same questions, allowing comparison.

[Ch 1] Quasi-experiment

Measures the impact of a naturally occurring event when ethics prevent experimental control.

[Ch 1] Ecological validity

How well behaviour studied in one setting (such as a lab test) reflects behaviour in other settings.

[Ch 1] Correlation vs causation; correlation coefficient

Correlation: changes in one factor go with changes in another. Causation: one event depends on another. The coefficient r runs from -1.0 to +1.0. Only experiments test causation.

[Ch 1] Longitudinal vs cross-sectional design

Longitudinal: same people followed over time (expensive, dropout). Cross-sectional: different ages at one time (cheap, but snapshots and groups may differ in more than age).

[Ch 1] Cohort sequential and microgenetic designs

Cohort sequential: several cohorts followed over time, separating age from cohort effects. Microgenetic: same children over a short period of rapid change.

[Ch 1] Cohort

A group of people born at about the same time who share certain experiences.

[Ch 1] Three ethical principles; IRBs

Freedom from harm, informed consent, confidentiality. Institutional review boards oversee the ethical soundness of research.

[Ch 2] Material vs symbolic tools

Material: observable objects and behaviour patterns. Symbolic: abstract knowledge systems, beliefs, values. Both mediate children's behaviour.

[Ch 2] Three ways children acquire cultural tools

Social enhancement (use a tool because it is available), imitation, explicit instruction (language and symbols).

[Ch 2] Cumulative cultural evolution

Variation in material and symbolic tools builds up over generations. Messy, not a harmonious march of progress.

[Ch 2] Genotype vs phenotype

Genotype: the genes you carry. Phenotype: observable traits resulting from genotype interacting with environment.

[Ch 2] DNA, chromosomes, genes

DNA: double-stranded molecule making up chromosomes. Chromosome: threadlike structure in the nucleus holding thousands of genes. Gene: segment of DNA with instructions. A pairs with T, G pairs with C.

[Ch 2] Somatic vs germ cells; chromosome counts

Somatic: body cells, 46 chromosomes (23 pairs). Germ: sperm and egg, 23 chromosomes. Zygote: 46.

[Ch 2] Mitosis vs meiosis

Mitosis (somatic cells): chromosomes double, one split, identical cells. Meiosis (germ cells): double, two splits, gametes with half the genetic material.

[Ch 2] How is sex determined?

23rd pair: XX female, XY male. SRY gene acts from the end of week 6 into week 7, only if a Y chromosome is present.

[Ch 2] Alleles; homozygous vs heterozygous

Alleles are forms of a gene (two per gene, one from each parent). Homozygous: same alleles. Heterozygous: different alleles.

[Ch 2] Dominant, recessive, incomplete dominance, codominance

Dominant: expressed. Recessive: not expressed, but a carrier can pass it on. Incomplete: intermediate trait. Codominant: both fully expressed.

[Ch 2] Polygenic inheritance

Most traits involve many genes, so the effect of any one gene or set of genes is a probability.

[Ch 2] Mutation

A change in DNA structure. Passed on only if in germ cells. Only source of new genes in the gene pool. Most are harmful.

[Ch 2] PKU vs Down syndrome vs Klinefelter

PKU: from normal inheritance of genes. Down Syndrome and Klinefelter: breakdown in transmission affecting chromosomes in a germ cell.

[Ch 2] Prenatal genetic tests

Amniocentesis, chorionic villus sampling (CVS), noninvasive prenatal diagnosis (NIPD). Genetic counselors help interpret results.

[Ch 2] Three gene-environment relations

Passive (parents supply genes and environment), evocative/reactive (child's traits draw responses), active/niche construction (child chooses and shapes environments).

[Ch 2] Niche construction and ecological inheritance

Individuals actively shape their environments; the modified environments then affect later generations.

[Ch 2] Phenotypic plasticity vs canalization

Plasticity: easily changed by environment. Canalized: develops nearly the same regardless of environment, e.g. language.

[Ch 2] Heritability

Degree to which variation in a trait among individuals is due to genetic differences. Ranges 0 to 1.

[Ch 2] Kinship studies

Family, twin and adoption studies, used to estimate heritability.

[Ch 2] Limits of heritability

Varies across populations; heritable does not mean environment has no effect; additive model ignores gene-environment interaction.

[Ch 2] Coevolution of culture and biology

Culture influences which genetic traits survive. Examples: lactose tolerance and the sickle-cell gene.

[Ch 3] Three periods of prenatal development

Germinal (conception to implantation, about 8 to 10 days); embryonic (implantation to end of week 8); fetal (week 9 to birth, about 38 weeks).

[Ch 3] Germinal period milestones

Zygote forms 24 to 30 hours after fertilization; 2 cells at 36 h; 4 at 48 h; 16 to 32 at 3 days; hollow ball of about 100 cells at 4 days; enters uterus day 4 to 5; implanted by day 12 to 14.

[Ch 3] Amnion, chorion, placenta

Amnion: membrane holding amniotic fluid. Chorion: surrounds amnion, becomes fetal part of placenta. Placenta: exchanges nutrients and waste between mother and fetus.

[Ch 3] Ectoderm, endoderm, mesoderm

Ecto: outer skin, nails, lens, inner ear, nervous system. Endo: digestive system and lungs. Meso: muscles, bones, circulatory system, inner skin.

[Ch 3] Cephalocaudal vs proximodistal

Cephalocaudal: head down. Proximodistal: centre of the body outward.

[Ch 3] Embryo weeks 3 and 4

Week 3: neural tube becomes spinal cord, brain areas divide, heart forms. Week 4: heart beats; limbs, eyes, ears, digestive system forming.

[Ch 3] Embryo weeks 5 to 8

5: lungs and hand plates. 6: head dominant, brain differentiated. 7: nerve cells, muscles, face and neck, genetic sexual differentiation. 8: ears fully formed, can move.

[Ch 3] Fetal period highlights

Ossification begins week 9; all birth movements by 15 weeks; senses develop and allow fetal learning; age of viability about the 7th month.

[Ch 3] Maternal stress and nutrition

Stress (raised cortisol) linked to low birth weight and long-term effects. Nutrition: about 2,000 to 2,800 calories, extra folic acid, calcium, iron. Under- and overnutrition both risky.

[Ch 3] Teratogen: definition and four influences on its effects

Environmental agent causing abnormalities or death. Effects depend on timing, amount and length of exposure, genetic susceptibility (fetus and mother), and postnatal environment.

[Ch 3] Fetal alcohol syndrome

A pattern of damage from heavy maternal drinking; part of the broader fetal alcohol spectrum disorder (FASD).

[Ch 3] Stages of labor

Contractions dilate the cervix; the baby is delivered; the afterbirth is delivered. Labor starts about 266 days after conception.

[Ch 3] Apgar scale

Rates heart rate, respiratory effort, reflex responsivity, muscle tone and color. Low score means immediate medical attention.

[Ch 3] Preterm and low birth weight cutoffs

Preterm: before 37 weeks. Low birth weight: under 5 lb 8 oz (2,500 g).

[Ch 4] What changes in the brain from birth to adulthood?

Most neurons exist at birth; brain becomes 4 times larger, mainly through more connections and myelination. Cortex is less mature than the brain stem at birth.

[Ch 4] Parts of a neuron

Dendrites receive messages; axon sends impulses to axon terminals; neurotransmitters cross the synaptic gap; myelin insulates the axon and speeds transmission.

[Ch 4] Neurulation, neurogenesis, synaptogenesis, myelination

Neural tube forms (about week 3); neurons are born; synapses overproduced; then pruned; myelin added at different ages in different regions.

[Ch 4] Synaptic pruning

Selective dying-off of nonfunctional synapses; unused connections die.

[Ch 4] Four lobes and their jobs

Frontal: motor control, complex functions. Parietal: touch, spatial. Temporal: hearing, language, memory, emotion. Occipital: vision.

[Ch 4] Amygdala vs hippocampus

Both limbic system. Amygdala: emotion. Hippocampus: memory formation.

[Ch 4] Experience-expectant vs experience-dependent

Expectant: pre-wired for experiences common to the species, during sensitive periods. Dependent: stores information unique to the individual.

[Ch 4] Perceptual narrowing

Newborns discriminate phonemes of all languages, then soon perceive only those of the language they hear.

[Ch 4] Newborn vision and visual preferences

Nearsighted at birth. Prefer sharp contours, patterns over plain, large patterns over small, and faces. Recognize mother's face.

[Ch 4] Newborn hearing preferences

Mother's voice over a stranger's, baby talk over adult-directed speech, native language over others.

[Ch 4] Visual preference technique; habituation

Two stimuli shown together to see which the baby prefers. Habituation: attention to a repeated stimulus declines; dishabituation: renewed attention to something new.

[Ch 4] Multimodal perception

Perceiving one object or event through more than one sense.

[Ch 4] Reflexes

Organized inborn responses (rooting, sucking, grasping, Moro). Building blocks for coordinated action like nursing and reaching.

[Ch 4] Classical vs operant conditioning

Classical: an existing behaviour becomes linked to a new stimulus (Pavlov). Operant: new behaviours through reinforcement and punishment.

[Ch 4] Temperament

Emotional and behavioural style consistent across situations and fairly stable. Genetically based, shaped by environment; same traits across cultures with different strengths.

[Ch 4] Chess and Thomas profiles

Easy 40% (easygoing, positive); Difficult 10% (active, irritable, irregular); Slow to warm up 15% (inactive, moody, slow to adapt).

[Ch 4] Newborn sleep, feeding and crying

Sleep about two-thirds of the time in short bouts. Feeding about every 3 hours, 4 by 2.5 months. Crying is early communication; less in cultures with prolonged holding.

[Ch 5] Motor milestones in infancy

Reaching and grasping in year 1; crawling by 8 to 9 months (wariness of heights appears); walking around 1 year; by 2 stacking blocks and turning pages.

[Ch 5] Gross vs fine motor skills

Gross: large muscles (crawling, walking). Fine: hands and fingers (grasping, stacking).

[Ch 5] Effects of early deprivation

Orphan studies show prolonged deprivation causes lasting intellectual impairment; the sensitive period for experience-expectant and experience-dependent brain development is 6 to 24 months.

[Ch 5] Schema

A mental structure that represents, organizes and interprets experience; the unit of knowledge. Few are innate.

[Ch 5] Assimilation vs accommodation

Assimilation: fit new experience into an existing schema. Accommodation: change the schema for a new experience.

[Ch 5] Equilibration and disequilibrium

Equilibration: balance between schemas and input. When assimilation keeps failing, disequilibrium pushes the child to reorganize.

[Ch 5] Piaget's four stages with ages

Sensorimotor 0 to 2; preoperational 2 to 6/7; concrete operational 6/7 to 12; formal operational 12 and up.

[Ch 5] Sensorimotor substage 1

0 to 1.5 months. Reflex activity: rooting, sucking, grasping, looking.

[Ch 5] Sensorimotor substage 2

1.5 to 4 months. Primary circular reactions: repeat pleasurable actions on own body.

[Ch 5] Sensorimotor substage 3

4 to 8 months. Secondary circular reactions: repeat actions that make interesting things happen to objects; imitates simple actions.

[Ch 5] Sensorimotor substage 4

8 to 12 months. Coordination of secondary circular reactions: intentionality, goal-directed behaviour, combining schemes, earliest problem solving.

[Ch 5] Sensorimotor substage 5

12 to 18 months. Tertiary circular reactions: deliberately varies actions to see results, the little scientist.