AQA A-level Psychology (7182): Paper 2 – Biopsychology – Study Guide

Biopsychology is the study of how the nervous system, hormones and brain structures relate to behaviour. In AQA A-level Psychology (7182) it is compulsory content examined on Paper 2: Psychology in Context. You need to describe the nervous and endocrine systems, neurons and synaptic transmission, the fight-or-flight response, localisation and lateralisation of function, split-brain research, plasticity and ways of studying the brain, and to evaluate the research behind them. Biological rhythms, part of earlier editions of the specification, are not in section 4.2.2 of Version 1.4.

This guide follows the AQA AS and A-level Psychology (7181, 7182) specification, Version 1.4 (1 September 2025), for teaching from September 2025. Biopsychology is section 4.2.2 of the specification and topic 6 in the A-level subject content. Use it with the Biopsychology revision notes and Biopsychology practice questions. The other Paper 2 topics are covered in the Approaches in Psychology guide and the Research methods guide.

How is Biopsychology examined on Paper 2?

Paper 2: Psychology in Context assesses compulsory content 5 to 7 (Approaches in Psychology, Biopsychology and Research methods). It is a 2-hour written exam worth 96 marks and 33.3% of the A-level. The specification lists three sections: Section A and Section B are each “multiple choice, short answer and extended writing, 24 marks”, and Section C is 48 marks. Biopsychology is the second of the three topics; your teacher will confirm which section carries it on your paper. The specification also states that research methods, practical skills and mathematical skills are assessed across all papers, so expect data and methods questions set in biological contexts.

Coverage table

Specification point	What it means for you
Divisions of the nervous system	Central and peripheral; somatic and autonomic
Neurons and synaptic transmission	Sensory, relay and motor neurons; neurotransmitters; excitation and inhibition
Endocrine system	Glands and hormones
Fight or flight	The response, including the role of adrenaline
Localisation and lateralisation	Motor, somatosensory, visual, auditory and language centres; Broca’s and Wernicke’s areas; split-brain research
Plasticity and functional recovery	How the brain changes and recovers after trauma
Ways of studying the brain	fMRI; EEG and event-related potentials (ERPs); post-mortem examinations

1. How is the nervous system organised?

The central nervous system (CNS) is the brain and spinal cord. The brain processes information and controls conscious thought and behaviour; the spinal cord relays messages between the brain and the body and controls simple reflexes. The peripheral nervous system (PNS) is every nerve outside the CNS. It has two divisions:

• The somatic nervous system carries sensory information to the CNS and motor commands to skeletal muscles; it controls voluntary movement.
• The autonomic nervous system controls involuntary functions such as heart rate, digestion and breathing. It has a sympathetic branch, which arouses the body for action, and a parasympathetic branch, which returns it to a resting state (“rest and digest”).

2. How do neurons communicate?

There are three types of neuron. Sensory neurons carry messages from receptors to the CNS; they have long dendrites and short axons. Relay neurons connect sensory and motor neurons inside the CNS and have short dendrites and short axons. Motor neurons carry messages from the CNS to muscles and glands; they have short dendrites and long axons. Every neuron has a cell body, dendrites that receive signals and an axon that carries the electrical impulse (action potential), often covered by a myelin sheath that speeds transmission.

Synaptic transmission is how a signal crosses the tiny gap (synapse) between neurons. When the action potential reaches the axon terminal, synaptic vesicles release a neurotransmitter into the synaptic cleft. The neurotransmitter diffuses across and binds to receptor sites on the postsynaptic neuron. The message is then converted back into an electrical signal, or not, depending on the effect. Transmission is one-directional because vesicles are only on the presynaptic side and receptors only on the postsynaptic side. The neurotransmitter is then broken down or taken back up (reuptake).

Excitation and inhibition. An excitatory neurotransmitter (such as adrenaline in the brain) makes the postsynaptic neuron more likely to fire. An inhibitory neurotransmitter (such as serotonin in many brain pathways) makes it less likely to fire. Whether the postsynaptic neuron fires depends on summation: the combined total of excitatory and inhibitory inputs it receives at once.

3. What does the endocrine system do?

The endocrine system uses glands to release hormones into the bloodstream, which carry them to target organs. It works more slowly than the nervous system but its effects last longer. Key glands include the pituitary (the “master gland”, controlled by the hypothalamus, releasing hormones that regulate other glands), the adrenal glands (adrenaline from the adrenal medulla; cortisol from the adrenal cortex), the thyroid (thyroxine, which affects metabolism), the pineal gland (melatonin, which affects sleep) and the ovaries and testes (oestrogen and testosterone).

4. What happens in the fight-or-flight response?

When the amygdala detects a threat, it signals the hypothalamus, which activates the sympathetic nervous system. The sympathetic nervous system stimulates the adrenal medulla, which releases adrenaline into the bloodstream. Adrenaline increases heart rate and blood pressure, dilates the pupils, increases breathing rate, releases glucose for energy and slows digestion, preparing the body to fight or run. When the threat passes, the parasympathetic nervous system returns the body to rest.

Evaluation: the response was adaptive for our ancestors facing physical threats, but modern stressors (exams, traffic) are rarely physical, so repeated activation can be harmful. Taylor et al. (2000) proposed that females more often show a “tend and befriend” response, protecting offspring and seeking social support, which suggests the classic model has a gender bias because early research mainly used males.

5. Where are functions located in the brain?

Localisation of function is the idea that specific areas of the brain have specific functions. The specification lists:

• Motor area: at the back of the frontal lobe; controls voluntary movement on the opposite side of the body.
• Somatosensory area: at the front of the parietal lobe; processes touch, temperature and pain from the opposite side of the body.
• Visual area: in the occipital lobe; each hemisphere receives input from the opposite visual field.
• Auditory area: in the temporal lobe; processes sound.
• Broca’s area: in the left frontal lobe; involved in speech production. Broca’s patient “Tan” could understand speech but could say little except “tan”; after his death Broca found damage in this area.
• Wernicke’s area: in the left temporal lobe; involved in language comprehension. Damage causes fluent but meaningless speech.

Evaluation. Brain-scan evidence supports localisation; for example, Petersen et al. (1988) used PET scans to show Wernicke’s area active when listening to words and Broca’s area when reading. However, Lashley (1950) removed areas of rats’ cortex and found learning was not lost from any single area, suggesting equipotentiality: higher functions are spread across the cortex. Plasticity also challenges strict localisation, because other areas can take over a damaged area’s function.

Hemispheric lateralisation is the idea that the two hemispheres differ in function. Language is usually lateralised to the left hemisphere, while the right is more involved in visual-spatial tasks and recognising faces.

Split-brain research. Sperry (1968) studied patients whose corpus callosum had been cut to treat severe epilepsy, so the hemispheres could no longer communicate. An image was shown to one visual field. When an object was shown to the right visual field (processed by the left hemisphere), the patient could name it. When shown to the left visual field (right hemisphere), the patient could not name it but could pick out the matching object with the left hand. This supported lateralisation of language to the left hemisphere. Evaluation: the sample was small and all had epilepsy, which may have affected brain organisation; and the procedure was highly standardised, which is a strength.

6. What is plasticity, and how does the brain recover?

Plasticity is the brain’s ability to change its structure and function in response to experience and learning. Synaptic connections are formed and lost throughout life (synaptic pruning removes rarely used connections). Maguire et al. (2000) found that London taxi drivers had more grey matter in the posterior hippocampus than control participants, and the amount correlated with time spent in the job, suggesting the brain changes with spatial learning.

Functional recovery after trauma such as stroke or injury happens when undamaged areas take over the function of damaged ones. Mechanisms include axonal sprouting (new nerve endings grow to connect with undamaged neurons), denervation supersensitivity (neurons become more sensitive to compensate) and recruitment of homologous areas on the opposite side of the brain. Evaluation: recovery appears to be affected by age (generally greater in younger people) and by education level, so individual differences matter. Research on plasticity has practical value for rehabilitation, which supports a holistic view of brain function.

7. How do psychologists study the brain?

Method	How it works	Strengths	Weaknesses
fMRI	Detects changes in blood oxygenation linked to neural activity	No radiation; good spatial resolution (a few millimetres)	Poor temporal resolution (a few seconds’ delay); expensive; shows correlation, not cause
EEG	Electrodes on the scalp record overall electrical activity as waves	Excellent temporal resolution; cheap; useful for sleep and epilepsy	Cannot pinpoint the source of activity deep in the brain
ERPs	EEG responses averaged over many trials to isolate the response to a specific stimulus	Excellent temporal resolution; links activity to a specific event	Background noise must be removed; standardisation varies between studies
Post-mortem examination	The brain is studied after death, often comparing with behaviour in life	Allows detailed study of deep structures; led to early discoveries (Broca’s Tan)	Damage may be caused by other factors, such as age or illness; consent issues

8. Are biological rhythms still on the specification?

No. Earlier editions of the AQA specification included biological rhythms, but section 4.2.2 of Version 1.4 (1 September 2025) does not, so no question will be set on them. Many textbooks still have a rhythms chapter; the summary below is background only, useful as evidence about the SCN and the pineal gland in endocrine or localisation answers.

Background, not specification content since Version 1.4: a circadian rhythm lasts about 24 hours, such as the sleep/wake cycle and core body temperature. Siffre spent long periods in caves without daylight or clocks; his sleep/wake cycle stayed rhythmic but lengthened to a little over 24 hours, suggesting an internal clock that is normally reset by light. Aschoff and Wever (1976) found similar results with participants living in a bunker.

An infradian rhythm lasts longer than 24 hours, such as the menstrual cycle (about 28 days). Stern and McClintock (1998) found that women’s menstrual cycles changed when they were exposed to underarm compounds from other women, suggesting pheromones can synchronise cycles. Seasonal affective disorder is another infradian (annual) rhythm.

An ultradian rhythm lasts less than 24 hours, such as the stages of sleep, which cycle roughly every 90 minutes through light sleep, deep (slow-wave) sleep and REM sleep. Dement and Kleitman (1957) used EEG to show that REM sleep is linked with dreaming.

Endogenous pacemakers are internal clocks. The suprachiasmatic nucleus (SCN) in the hypothalamus is the main one: it receives information about light from the optic chiasm and controls the pineal gland, which releases melatonin to promote sleep when it is dark. Ralph et al. (1990) transplanted SCN cells from mutant hamsters with a 20-hour rhythm into normal hamsters, which then adopted the 20-hour rhythm. DeCoursey et al. (2000) found that chipmunks with SCN damage returned to the wild had disrupted sleep/wake cycles and many were killed by predators.

Exogenous zeitgebers are external cues that reset the internal clock. Light is the most important: it resets the SCN. Social cues, such as meal times, also help entrain rhythms, which is why travellers are advised to adopt local eating and sleeping times to reduce jet lag. Campbell and Murphy (1998) reported that light shone on the backs of participants’ knees could shift their sleep/wake cycle, though later studies did not replicate this.

Evaluation: much rhythm research uses animals or very small samples (Siffre was one person), which limits generalisation. Pacemakers and zeitgebers work together; studying one alone is reductionist. Research has applications, for example to shift work and to timing medication (chronotherapeutics).

Common errors

• Writing that the somatic system controls heart rate; that is the autonomic system.
• Saying neurotransmitters travel “along” the axon; they cross the synapse.
• Mixing up Broca’s area (production) and Wernicke’s area (comprehension).
• Reversing split-brain findings: the left hemisphere (right visual field) can name objects.
• Revising biological rhythms as if they were examinable; Version 1.4 removed them.
• Describing fMRI as recording electrical activity; that is EEG.

Frequently asked questions

What is the difference between the sympathetic and parasympathetic nervous systems? Both are branches of the autonomic nervous system. The sympathetic branch prepares the body for action (fight or flight), while the parasympathetic branch calms it and conserves energy once the threat has passed.

Is localisation of function proven? Strong evidence supports localisation of basic functions such as motor control and language, but higher functions such as memory appear more distributed, and plasticity shows functions can move after damage.

Are biological rhythms on the AQA specification? Not in Version 1.4 (1 September 2025). Section 4.2.2 lists the nervous and endocrine systems, neurons and synaptic transmission, fight or flight, ways of studying the brain, localisation, lateralisation, split-brain research, plasticity and functional recovery.

Which glands should I know for the endocrine system? The specification says only “glands and hormones”, so learn a few well: the pituitary (controlled by the hypothalamus), the adrenal glands (adrenaline from the medulla, cortisol from the cortex), the thyroid (thyroxine) and the pineal gland (melatonin).

Where to go next

Condense this guide with the Biopsychology revision notes, then test yourself with the Biopsychology practice questions. See the AQA A-level Psychology hub and the AQA A-level Psychology checklist.

Official syllabus

AQA AS and A-level Psychology (7181, 7182) specification, Version 1.4 (1 September 2025), section 4.2.2 Biopsychology — aqa.org.uk.