1What developmental psychology studies
Developmental psychology studies how people change from conception to old age. It looks at three areas: physical development, cognitive development (thinking) and social and emotional development.
A few big questions return in every topic:
- Nature or nurture: how much comes from genes and how much from experience. Today most researchers study how the two interact.
- Continuity or stages: does change happen gradually, or in separate stages with new ways of thinking?
- Critical or sensitive periods: a critical period is a fixed time window in which an experience must happen; a sensitive period is a time when it has the strongest effect.
Two research designs are central. A cross-sectional study compares different age groups at one moment. It is quick, but differences can be cohort effects, caused by growing up in different times. A longitudinal study follows the same people over years. It shows real change, but takes long and loses participants.
Self-check A study tests 20-, 50- and 80-year-olds once and finds that the oldest group uses computers worst. Why may this not show an effect of ageing?
- Cross-sectional studies cannot measure computer skills
- It may be a cohort effect: the groups grew up with different technology
- Longitudinal studies always show smaller effects
- The sample is too young
Answer: It may be a cohort effect: the groups grew up with different technology. In a cross-sectional design, age groups also differ in the era they grew up in. Reading the difference as ageing alone ignores this cohort effect.
2Cognitive development: Piaget and Vygotsky
Piaget saw children as active learners who build schemas, mental frameworks for understanding the world.
- Assimilation: fitting new information into an existing schema, such as calling a cow a “doggy”.
- Accommodation: changing the schema when it does not fit, such as learning that cows and dogs are different.
- Equilibration: the drive to restore balance between schemas and experience.
Piaget described four stages in a fixed order:
- Sensorimotor (0–2 years): learning through senses and actions. Object permanence, knowing that hidden objects still exist, develops from about 8 months.
- Preoperational (2–7): language and pretend play grow, but thinking is egocentric (children struggle to see another person’s view, as in the three mountains task) and children fail conservation tasks.
- Concrete operational (7–11): logical thinking about real objects. Children understand conservation, reversibility and seriation (ordering by size).
- Formal operational (11+): abstract and hypothetical reasoning.
Later studies suggest Piaget underestimated young children. With simpler or more natural tasks, such as the “naughty teddy” version of conservation, more young children succeed.
Vygotsky stressed social learning. The zone of proximal development is the gap between what a child can do alone and what they can do with help. Adults support learning by scaffolding: giving help and withdrawing it as the child improves.
Theory of mind is understanding that others have their own beliefs. In the Sally–Anne false-belief task, most children pass from about 4 years of age.
Self-check A toddler sees a cow for the first time and says “doggy”. Which process is this?
- Accommodation
- Assimilation
- Conservation
- Object permanence
Answer: Assimilation. The child fits the new animal into an existing schema (four legs, fur: dog). Accommodation would be changing the schema to make a new category for cows.
3Social and emotional development
Attachment is the close emotional bond between an infant and a caregiver. Bowlby argued that it is innate, that infants have one main attachment figure (monotropy) and that early bonds form an internal working model for later relationships.
Harlow’s monkeys preferred a soft cloth “mother” to a wire one that gave milk: contact comfort mattered more than food. Schaffer and Emerson found that babies attach most strongly to sensitive, responsive carers, who need not be the ones who feed them, and that many form several attachments.
Ainsworth’s Strange Situation observes a 1-year-old during separations from and reunions with the caregiver:
- Secure: upset at separation, seeks comfort at reunion and is soon calmed. This is the most common type.
- Insecure-avoidant: shows little distress and ignores or turns away from the caregiver at reunion.
- Insecure-resistant (ambivalent): very distressed and both seeks and resists contact at reunion.
- Disorganised (added later by Main and Solomon): confused or contradictory behaviour.
Parenting styles (Baumrind, extended by Maccoby and Martin) combine warmth and demands: authoritative (warm and firm), authoritarian (strict, little warmth), permissive (warm, few rules) and neglectful (neither).
Erikson described eight psychosocial crises across life, such as trust versus mistrust in infancy, identity versus role confusion in adolescence, intimacy versus isolation in young adulthood and integrity versus despair in old age.
Kohlberg described moral reasoning in three levels: preconventional (avoiding punishment, getting rewards), conventional (being a good person, following laws) and postconventional (universal principles). Gilligan criticised it for ignoring an ethic of care.
Self-check In the Strange Situation, an infant shows little distress when the mother leaves and ignores her when she returns. Which type is this?
- Disorganised
- Insecure-avoidant
- Insecure-resistant (ambivalent)
- Secure
Answer: Insecure-avoidant. Little distress plus avoiding the caregiver at reunion is the avoidant pattern. Resistant infants are the opposite: very distressed, then seeking and pushing away contact.
5A worked example
Follow the reasoning. Try to say the next step before you open it.
Worked exampleA 5-year-old agrees that two short, wide glasses hold the same amount of juice. You pour one into a tall, thin glass. She now says the tall glass has more. Explain this with Piaget, and give one criticism.
1At 5 years the child is in Piaget’s preoperational stage (2–7 years).
2This is a conservation task: the amount stays the same although the appearance changes. The child fails it.
3She shows centration: she focuses on one feature, the height of the juice, and ignores the width.
She also lacks reversibility: she does not mentally pour the juice back to see it is the same amount.
4According to Piaget, children conserve liquid in the concrete operational stage, from about 7 years.
5When the change looks accidental, as in McGarrigle and Donaldson’s “naughty teddy” study, more young children conserve. Asking the same question twice may also make children think the answer should change.
Answer She is preoperational: centration and no reversibility make her fail conservation; but simpler task versions show that Piaget underestimated young children.
7How exam questions look
- Easy (key terms and facts): stages, names and definitions. Piaget’s first stage, who developed attachment theory, when first words appear (about 12 months).
- Medium (applying the concepts): a child’s behaviour to classify. You name the stage, the attachment type, the parenting style or the identity status.
- Hard (cases and analysis): classic studies and their meaning. You interpret findings such as the Romanian orphan studies, Schaie’s longitudinal data or adoption studies, and judge what they show about a theory.
For hard questions, check the design as well as the result. Ask whether the finding could come from a cohort effect, a misleading task or genes and environment acting together.