Capstone: Development Across the Life Span

This is Unit Eighteen, the capstone, part one, on theoretical perspectives and language across the lifespan. Unit Seventeen closed on a good death across cultures. The capstone teaches nothing new; it gathers threads from the whole course. Carry one question through this part: when the course's big frameworks are gathered from every unit, how well do they hold up? For theories of stages, the answer comes at the entry that weighs stages against evidence. For language, it comes at the entry that weighs nature against nurture. By the end you will be able to name the five families of theory. To put Piaget's stages and Erikson's crises in order. To state what the evidence says about stage theories. To put the early language milestones in order, and assign an error to its layer. And to explain how nature and nurture combine in language.

Four entries: how the capstone works, the stage question, the families of theory, and one theory that fits every age.

How to use this unit.

HGD 2551 How to Use This Unit

The capstone teaches nothing new. It runs four threads through the course, theoretical perspectives, language, perception and intelligence, the four exam categories the body covers most thinly, in four arcs of ten entries, each naming by number the earlier entries that carry its claims. Where a claim was contested upstream, the entry named still carries its evidence.

Continuous, or stage-like?

HGD 2552 Continuous or Stage-Like

Theoretical perspectives begin with unit one's question: is development continuous, gradual day-by-day progress, or discontinuous, a change in kind? The staircase of long landings and short climbs is the picture behind Piaget's and Erikson's stages. One change can show both patterns, as puberty looks sudden on top of continuous preparation.

The families of theory.

HGD 2553 The Families of Theory

Unit one grouped theories into families: psychodynamic, from Freud; learning theory; sociocultural, from Vygotsky; information processing; and ecological, from Bronfenbrenner. One toddler's tantrum can be explained five ways, one per family. Each family asks a different question, so the course uses them together rather than choosing one winner.

Bronfenbrenner across the lifespan.

HGD 2554 Bronfenbrenner Across the Lifespan

Bronfenbrenner's nested systems recur across the course: in infancy, where a distant change reaches the infant through the other layers; in supports for struggling children; and in the CDC's grouping of suicide risk, which unit eleven said mirrors his systems. Influence moves inward, layer by layer, in every age band.

Five entries on the great stage theorists, gathered from across the course.

Piaget's stages, in order.

HGD 2555 Piaget's Stages in Order

Piaget's four stages run through four units. The sensorimotor stage, birth to about two, builds understanding through the senses and action, ending in symbolic thought and deferred imitation. The preoperational stage, about two to seven, brings symbolic representation and pretend play, but also egocentrism and centration. The concrete operational stage, about seven to eleven, brings conservation, reversibility, class inclusion and seriation. The formal operational stage, from about eleven or twelve, brings reasoning about possibilities. The ages are approximate. Exam items name a behaviour and ask the stage: object permanence, sensorimotor; failing conservation, preoperational; logic about real objects, concrete; hypothetical reasoning, formal.

Piaget's critics.

HGD 2556 Piaget's Critics

Each Piaget unit carried a critique: infants show object permanence earlier than he thought; the order holds but ages vary by culture, and preschoolers have passed conservation early; and formal operations are not universal. The criticisms qualify the timing and universality of the stages, not the sequence itself.

Erikson's crises, in order.

HGD 2557 Erikson's Crises in Order

Erikson's eight crises run through the whole course. Trust versus mistrust fills the first year; autonomy versus shame and doubt follows; initiative versus guilt runs from about three to six; industry versus inferiority spans the elementary years; identity versus role confusion, about twelve to eighteen; intimacy versus isolation in early adulthood; generativity versus stagnation in midlife; and integrity versus despair at life's end. The age bands are approximate, textbooks differ, and the crises have been criticized for fitting some cultures better than others. Exam items describe a central struggle and ask for the crisis.

Vygotsky, beside Piaget.

HGD 2558 Vygotsky Beside Piaget

Vygotsky's sociocultural theory holds that thinking develops through social tools and help from others, within the zone of proximal development, and scaffolding, support withdrawn as competence grows, shows in a teacher's hints to a struggling student. Classrooms draw on both theorists: constructivism from Piaget and guided interaction from Vygotsky.

Freud's legacy.

HGD 2559 Freud's Legacy

Freud's psychosexual stages are the most disputed classic: hard to test and failed on key claims, while unconscious processes and ego defenses have research support, as in Vaillant's mature defenses, a psychoanalytic idea tested in a long-term study. Erikson's psychosocial theory is psychodynamic theory's lifespan descendant.

One entry that sets every stage claim in the course beside its evidence. The first half of the opening question is answered here.

The first payoff: stages against evidence.

HGD 2560 Stages Against Evidence

Across the course, stage theories met the same test. Unit one defined them as bursts of change between stretches of stability. Piaget's stages held up in sequence but not in timing: concrete operations appear before seven, and formal operations are not universal. Arnett's emerging adulthood describes a period many young people in affluent societies pass through, not a universal stage. The adult stage theories drew largely on men, small samples and single cohorts, and the midlife crisis is not typical. At life's end, Kübler-Ross's five themes were never tested as a sequence before the Yale study, and the dual-process model replaced stages with oscillation. That answers the first half of this part's question. The misconception is either extreme: that stages are fixed timetables, or that they are useless. They describe typical sequences and common tasks; real development is more continuous, more variable and more shaped by culture and cohort.

Four entries on language from the start: what it is, its first milestones, its theories, and its layers.

What language is.

HGD 2561 What Language Is

Language is a communication system of words and rules with infinite generativity; productive language is speaking or signing, receptive language is understanding. A toddler may follow a two-step request but say only a dozen words, since understanding runs ahead of speaking throughout early childhood.

The first words, in order.

HGD 2562 First Words in Order

Early language follows a reliable order. Crying is present from birth. Cooing, vowel sounds, arrives by about two months. Babbling, repeated consonant-vowel sounds, begins around four to seven months and narrows toward the languages heard. Pointing appears around nine to twelve months, and first words around twelve months. Telegraphic two-word speech follows at eighteen to twenty-four months, with a vocabulary spurt. The order is similar across cultures, suggesting a biological base, while the ages vary. Exam items give a behaviour and an age and ask whether it is on time.

Theories of language.

HGD 2563 Theories of Language

Three accounts of language acquisition appear in unit three: Chomsky's nativist device, Skinner's learning by reinforcement with Bandura's imitation, and the interactionist view of readiness meeting a social world. Learning alone cannot explain language, and toddlers learn words better face to face than from video.

The layers of language.

HGD 2564 The Layers of Language

Language can be described in layers. Phonology is the sound system, built of phonemes. Morphology is units of meaning, morphemes. Semantics is meaning in context, and syntax the rules for combining words, while grammar is the whole rule system. Pragmatics is using language appropriately with real people in real settings. Preschoolers progress in every layer at once. Exam questions describe an error and ask its layer: goed is grammar, a rule overapplied; doggie for every animal is semantics; talking over a teacher is pragmatics.

Five entries following language through the lifespan, from private speech to late life.

Private speech, and thought.

HGD 2565 Private Speech and Thought

Vygotsky saw private speech, talking to oneself through a hard task, as evidence that language guides cognition, like a five-year-old narrating her puzzle moves under her breath. The Sapir-Whorf hypothesis holds that language shapes thought; its strong form, that language determines thought, is probably wrong.

Sensitive periods for language.

HGD 2566 Sensitive Periods for Language

Childhood is the optimal time for a first and a second language, and learners who start before about ten are often indistinguishable from native speakers, a sensitive period rather than a critical one. Early access to a full language protects development, as with a deaf toddler signing fluently with deaf parents.

Two languages.

HGD 2567 Two Languages

Bilingual infants reach milestones on the usual schedule, bilingual preschoolers may mix languages at first, and the cognitive advantage of bilingualism is contested. Two languages neither confuse children nor reliably make them smarter.

Pragmatics across childhood.

HGD 2568 Pragmatics Across Childhood

Pragmatics grows from turn-taking in preschool, to the hidden rules of school-age talk, to code-switching as identity work in adolescence, like a teen speaking one way with family, another at school and a third at a job interview. Code-switching signals competence in both varieties, not confusion.

Language in late life.

HGD 2569 Language in Late Life

Language holds up in late life: semantic memory, facts and vocabulary, stays intact, even as tip-of-the-tongue retrieval blocks increase, like a seventy-year-old recalling an actor's name an hour later. The problem is retrieval, not loss, and vocabulary rises into the seventies in the Seattle study.

One entry to close the part, on language as the clearest case of nature and nurture together. The second half of the opening question is answered here.

The second payoff: nature and nurture in language.

HGD 2570 Nature and Nurture in Language

Language is the course's clearest case of nature and nurture working together, the theme unit one introduced, and it answers the second half of this part's question. The evidence for nature is strong: milestones follow a similar order across cultures, Chomsky's nativist account points to an innate device, and sensitive periods fit a biological clock. But nurture is equally visible. Children with no language input in the first two years risk never achieving fluency, so the clock needs input to run. Family talk varies widely within and across income groups, toddlers learn better face to face than from video, and reinforcement and imitation capture part of the story. The misconception is that language is either innate or learned. The interactionist view is usually the answer: biological readiness interacts with a social environment, because language exists for communication. Both halves of the debate are real.

Look at what you can now do. You can name the five families of theory: psychodynamic, learning, sociocultural, information processing and ecological. You can put Piaget's four stages in order, from sensorimotor to formal operations, and Erikson's eight crises, from trust to integrity. You can state the course's finding on stages: typical sequences and common tasks, qualified in timing, universality and sequence. You can put the milestones in order, from crying to two-word speech, and assign an error to its layer. And you can explain language as readiness meeting a social world, the interactionist answer. Part two runs the last two threads: perception and intelligence.