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The human brain is the most complex organ in the body, containing approximately 86 billion neurons. Understanding the basic structure of the brain is essential for GCSE Psychology, as it underpins topics such as memory, perception, language, and psychological disorders. The brain is divided into distinct regions, each responsible for different functions.
The cerebral cortex is the outer layer of the brain, often called grey matter due to its colour. It is the largest part of the human brain and is responsible for higher cognitive functions such as thinking, reasoning, language, memory, and voluntary movement.
The cerebral cortex is divided into two hemispheres (left and right), connected by a thick band of nerve fibres called the corpus callosum. Each hemisphere is divided into four lobes:
The frontal lobe is located at the front of the brain. It is the largest lobe and is responsible for:
| Function | Description |
|---|---|
| Voluntary movement | The motor cortex (in the frontal lobe) controls conscious movements of the body |
| Higher cognitive functions | Reasoning, planning, problem-solving, decision-making |
| Personality and behaviour | Involved in personality expression and social behaviour |
| Speech production | Broca's area (in the left frontal lobe) is responsible for producing speech |
Key case study: Phineas Gage (1848) — a railway worker who survived a metal rod being driven through his frontal lobe. His personality changed dramatically — he became impulsive, rude, and unable to plan ahead. This case provided early evidence that the frontal lobe is involved in personality and decision-making.
The temporal lobe is located at the sides of the brain (near the temples). It is responsible for:
| Function | Description |
|---|---|
| Auditory processing | Processing sounds and interpreting speech |
| Memory | The hippocampus (located within the temporal lobe) is crucial for forming new long-term memories |
| Language comprehension | Wernicke's area (in the left temporal lobe) is responsible for understanding language |
The parietal lobe is located at the top of the brain, behind the frontal lobe. It is responsible for:
| Function | Description |
|---|---|
| Somatosensory processing | Processing sensory information from the body (touch, temperature, pain, pressure) |
| Spatial awareness | Understanding the position of the body in space and the location of objects |
| Numerical processing | Involved in mathematical thinking and calculations |
The occipital lobe is located at the back of the brain. Its primary function is:
| Function | Description |
|---|---|
| Visual processing | Contains the visual cortex, which processes information from the eyes — interpreting colour, shape, depth, and movement |
Damage to the occipital lobe can result in visual impairments or blindness, even if the eyes themselves are functioning normally.
The cerebellum (meaning "little brain") is located at the back and base of the brain, beneath the occipital lobe. It is responsible for:
Damage to the cerebellum results in ataxia — uncoordinated, clumsy movements, difficulty with balance, and problems with fine motor skills.
The cerebellum is also associated with procedural memory — the memory for how to do things (e.g. tying shoelaces, playing piano). This explains why procedural memories are often preserved even when other types of memory are damaged.
| Brain Region | Location | Key Functions |
|---|---|---|
| Frontal lobe | Front | Movement, thinking, planning, personality, speech production (Broca's area) |
| Temporal lobe | Sides | Hearing, memory, language comprehension (Wernicke's area) |
| Parietal lobe | Top | Touch, spatial awareness, numerical processing |
| Occipital lobe | Back | Vision (visual cortex) |
| Cerebellum | Back/base | Coordination, balance, motor learning, procedural memory |
graph TD
Brain["Brain<br/>cerebral cortex + cerebellum"] --> Cortex["Cerebral cortex<br/>two hemispheres"]
Brain --> Cb["Cerebellum<br/>coordination, balance,<br/>procedural memory"]
Cortex --> F["Frontal lobe<br/>movement, planning,<br/>personality, Broca area"]
Cortex --> T["Temporal lobe<br/>hearing, memory,<br/>Wernicke area"]
Cortex --> P["Parietal lobe<br/>touch, spatial awareness,<br/>numbers"]
Cortex --> O["Occipital lobe<br/>vision / visual cortex"]
Cortex --> CC["Corpus callosum<br/>connects hemispheres"]
Exam Tip: You must be able to identify and describe the function of each lobe and the cerebellum. A common question format is: "Describe the role of [brain region]." Always state both the location and the function.
To understand brain structure in context, it helps to know where the brain sits within the wider nervous system.
Nervous System
Central Nervous System (CNS) = brain + spinal cord
Peripheral Nervous System (PNS) = all nerves outside CNS
Somatic NS = controls voluntary skeletal muscles
Autonomic NS = controls involuntary organs
Sympathetic = fight or flight (arousing)
Parasympathetic = rest and digest (calming)
The brain is the command centre of the CNS. The cortex we study in this lesson sits at the top of this hierarchy — it is the "executive" of the nervous system.
Aim: To document the behavioural and psychological consequences of damage to a specific brain region — the frontal lobe — and so contribute to the debate about localisation of function.
Procedure: Phineas Gage was a 25-year-old railway foreman for the Rutland and Burlington Railroad in Vermont, USA. On 13 September 1848 a premature explosion drove a tamping iron (1.1 m long, 3 cm thick, 6 kg) through his left cheek, behind his left eye, and out of the top of his skull. The iron destroyed much of Gage's left frontal lobe. He remained conscious throughout and was treated by Dr John Martyn Harlow, who observed him over the following years and published two case reports (1848 and 1868). Harlow compared Gage's pre- and post-accident behaviour based on interviews with Gage's employers, family, and doctors.
Findings: Gage survived and retained his language, memory, motor skills, and general intellect. However, his personality changed dramatically. Before the accident he was reliable, courteous, and described as "the most efficient and capable foreman in their employ". Afterwards, according to Harlow, he became "fitful, irreverent, indulging at times in the grossest profanity, impatient of restraint or advice". He could no longer plan ahead, make appropriate social judgements, or hold down a job. Friends said he was "no longer Gage".
Conclusion: The frontal lobe is essential for personality, planning, and social behaviour, not just movement. Damage to this region spares basic cognitive and motor functions but disrupts higher-order "executive" abilities. Gage's case provided some of the first evidence that specific brain regions support specific psychological functions — a principle known as localisation of function.
GRAVE evaluation:
Misconception: "The cerebellum is just for balance."
The cerebellum does coordinate movement and balance, but it is also central to procedural memory (how to ride a bike, type, or play the piano) and is increasingly recognised as contributing to cognitive processes such as language, attention, and emotional regulation. Damage to the cerebellum can produce ataxia (clumsy, uncoordinated movement) but also cognitive and mood changes. A common exam error is to describe the cerebellum only in terms of balance — always include motor learning and procedural memory.
Example 9-mark question: "Describe and evaluate what psychologists have learned about brain structure from the case of Phineas Gage. (9 marks)"
Grade 3-4 answer (basic):
Phineas Gage had an accident where a metal rod went through his brain. He lived but he changed. He became rude and could not keep a job. This shows the frontal lobe affects personality. A weakness is it only happened to one person.
Why it gets 3-4 marks: Correct outline, limited terminology, only one evaluation point.
Grade 5-6 answer (clear):
In 1848 Phineas Gage, a 25-year-old railway worker, had a tamping iron driven through his left frontal lobe in an explosion. He survived, and his language, memory, and motor skills were intact. However, his personality changed dramatically — he became impulsive, rude, and unable to plan. His friends said he was "no longer Gage". This suggests the frontal lobe is responsible for personality and decision-making, supporting the idea of localisation of function. A strength is that the case provided unusual and powerful real-life evidence. A weakness is that as a single case it cannot be generalised, and the reports of his personality change may have been exaggerated by later writers.
Why it gets 5-6 marks: Accurate detail, correct terminology, balanced evaluation.
Grade 7-9 answer (sophisticated):
Phineas Gage's 1848 accident — in which a tamping iron destroyed much of his left frontal lobe — remains one of the most influential case studies in neuropsychology. Harlow's observation that Gage survived with intact language, memory, and motor function, yet showed a profound change in personality, decision-making, and social behaviour, provided early evidence for localisation of function, specifically the frontal lobe's role in executive and social processes. The case prefigured later discoveries about frontal-lobe syndromes following stroke or tumour. However, several limitations apply. As an N=1 case study, it lacks generalisability. Contemporary reports are inconsistent, and historian Malcolm Macmillan (2000) argued that some accounts exaggerated Gage's personality change, noting evidence he later worked as a stagecoach driver in Chile. Additionally, the causal inference is complicated because his damage was non-selective and probably affected multiple regions. Modern neuroimaging studies (e.g. Damasio et al., 1994, who reconstructed the lesion) have largely confirmed the frontal-lobe role in executive function, lending convergent validity to Harlow's observations.
Why it gets 7-9 marks: Accurate detail, modern reconstruction, critical evaluation, convergent evidence.
Try these from memory, then check against the sections above:
If you can answer all eight without looking back, your recall of brain structure is exam-ready. If not, revisit the relevant summary table.
The structures you have mapped in this lesson feature throughout the rest of the AQA neuropsychology topic: the frontal lobe appears again in Sperry's split-brain research and Penfield's motor mapping; the temporal lobe in Tulving's PET scan study and the HM case; the parietal lobe and occipital lobe in discussions of the somatosensory and visual cortices. A clear mental picture of brain anatomy now will make every subsequent lesson easier.
This content is aligned with the AQA GCSE Psychology (8182) specification, Paper 2: Social context and behaviour — Brain and neuropsychology. For the most accurate and up-to-date information, please refer to the official AQA specification document.