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IB DP Psychology — Biological Approach | SL & HL | Paper 1
🎯 Learning Intentions By the end of this note, you will be able to:
- Define neuroplasticity, synaptic pruning, and long-term potentiation using IB-aligned terminology.
- Explain how experience-dependent plasticity allows the brain to reorganise itself in response to learning, injury, and environmental demands.
- Describe the role of synaptic strengthening and pruning in shaping neural pathways across the lifespan.
- Evaluate research evidence for neuroplasticity using supporting and opposing studies in ACAS format.
- Apply neuroplasticity concepts to a real-world case study from the biological perspective.
- Discuss the extent to which neuroplasticity provides a complete explanation of learning, recovery, and behavioural change.
- Analyse neuroplasticity research using relevant concept areas: Causality, Bias, Perspective, and Change.
Introduction & Context
Imagine you decide to learn a new language. At first, every new word feels effortful and unfamiliar. But after weeks of practice, phrases begin to flow more naturally, and what once required intense concentration becomes almost automatic. Something has changed — not just in your habits or motivation, but physically, inside your brain. The question is: what exactly is changing, and how does it happen?
For much of the twentieth century, scientists believed that the adult brain was essentially fixed — a hardwired structure that, once formed, could not meaningfully change. This view has been overturned by decades of research showing that the brain is far more dynamic than anyone imagined. Neural connections form, strengthen, weaken, and disappear throughout our entire lives in direct response to our experiences. This capacity for change is one of the most important discoveries in modern neuroscience, and it sits at the heart of the biological approach to psychology.
🔌 Analogy — The Path Through a Field Imagine a large field of tall grass. The first time you walk across it, you have to push through the grass with effort. But every time you walk the same route, the grass gets flattened a little more. Eventually, a clear path forms — easy to walk, hard to miss. If you stop using that path, the grass slowly grows back. The brain works in a similar way: frequently used neural connections become stronger and more efficient, while unused ones gradually fade. Neuroplasticity is the brain's ability to create, reinforce, and remove these paths based on experience.
Core Concepts
To understand how the brain changes, we first need to appreciate what it is made of. The brain contains approximately 86 billion neurons, each capable of forming thousands of connections with other neurons. These connections — called synapses — are the physical basis of everything we think, feel, remember, and do. The key insight of modern neuroscience is that these connections are not permanent: they are constantly being built, modified, and removed based on what we experience.
📖 Key Definition — Neuroplasticity Neuroplasticity (also called neural plasticity or brain plasticity) refers to the brain's ability to reorganise itself by forming new neural connections and modifying existing ones throughout the lifespan. This reorganisation occurs in response to learning, experience, environmental demands, and injury.
Neuroplasticity is not a single process but an umbrella term for several related mechanisms. It includes the growth of new synaptic connections (synaptogenesis), the strengthening of frequently used pathways, the