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IB DP Psychology — Concepts (Change) | SL & HL | Paper 1
🎯 Learning Intentions By the end of this note, you will be able to:
- Define development, maturation, and the concept of change in psychology using IB-aligned terminology.
- Explain the difference between change driven by experience and change driven by biological maturation, and why this distinction matters for research design.
- Describe the key features of longitudinal, cross-sectional, and cross-sequential research designs and the conditions under which each is most appropriate.
- Evaluate research evidence on developmental change using supporting and opposing studies in ACAS format.
- Apply concepts of development and maturation to a real-world case study from the sociocultural and biological perspectives.
- Discuss the extent to which research designs used in developmental psychology can establish whether change is caused by age, experience, or cohort effects.
- Analyse developmental research using relevant concept areas: Causality, Measurement, Bias, and Perspective.
Introduction & Context
Think about a photograph of yourself from five years ago. You look different, you think differently, and you probably behave differently too. Some of those changes happened because you grew older — your brain matured, your hormones shifted, your body changed in ways that were largely inevitable. But other changes happened because of what you experienced: the friendships you made, the challenges you faced, the culture you absorbed. The question at the heart of developmental psychology is deceptively simple: when a person changes over time, what is actually driving that change?
This question is not merely philosophical — it has profound practical consequences. If a child's reading difficulties stem from a brain that simply has not matured yet, the appropriate response is patience and time. But if those difficulties stem from a lack of stimulating early experiences, the appropriate response is intervention and enrichment. Getting the answer wrong has real costs. Developmental psychologists therefore invest enormous effort in designing research that can distinguish between these two sources of change, and understanding those research designs is essential for evaluating any claim about how and why people change across the lifespan.
🔍 Analogy — The Oak Tree and the Gardener Imagine planting an oak tree. Some of its growth is entirely predetermined — it will grow taller each year, produce acorns at a certain age, and shed its leaves in autumn regardless of what the gardener does. That is maturation: a biologically programmed sequence of change. But whether the tree grows tall and strong or stunted and weak depends enormously on the soil it is planted in, the water it receives, and the space it is given. That is development shaped by environment and experience. Developmental psychology tries to work out how much of the tree's final form was written in its seeds, and how much was written by the garden.
Core Concepts
Before we can evaluate any research on how people change, we need to be precise about what kind of change we are actually talking about. Psychologists draw a careful distinction between two overlapping but distinct processes: maturation and development. Understanding this distinction is the foundation of everything else in this topic.
📖 Key Definition — Maturation Maturation refers to the biologically programmed sequence of physical and psychological changes that unfold with age, largely independent of specific environmental experiences. These changes are universal across the species and follow a predictable timetable — for example, the development of object permanence in infancy, the onset of puberty in adolescence, or the gradual decline of working memory speed in later adulthood.
Maturation is essentially the body and brain following their genetic blueprint. A child does not need to be taught to walk — given a typical environment, the motor cortex, cerebellum, and