Biopsychology — AQA A-Level Psychology
Test yourself on Biopsychology with AQA A-Level practice questions.
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Biopsychology explained
The nervous system is the body's fast, electrical messaging network, and the marks are in the branching diagram.
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The central nervous system is the brain plus the spinal cord: the brain is where conscious decisions are made, while the spinal cord relays messages up and down and runs reflexes without waiting for the brain. Everything outside those two structures is peripheral, and it divides twice. The somatic branch carries sensory information in from receptors and motor commands out to skeletal muscle, and it is under voluntary control. The autonomic branch is involuntary, governing organs and glands through a sympathetic division that arouses the body and a parasympathetic division that restores it. Strong answers place a structure, name its job, then apply it: a thumping heart before a performance is sympathetic, not somatic.
The structure and function of sensory, relay and motor neurons. The process of synaptic transmission, including reference to neurotransmitters, excitation and inhibition.
A neuron carries information electrically along its own length and chemically to the next cell. Sensory neurons run from receptors to the CNS and have long dendrites and short axons; relay neurons lie within the CNS connecting the other two and have short dendrites and short axons; motor neurons run from the CNS to muscles and glands, with short dendrites and one long axon. At rest the inside of the cell is negatively charged, roughly -70 millivolts; a strong enough stimulus depolarises it and an action potential travels down the axon. At the terminal, vesicles fuse and release neurotransmitter into the synaptic cleft, where it diffuses across and binds to receptors on the postsynaptic dendrite. Excitatory transmitters such as glutamate make firing more likely; inhibitory ones such as GABA and serotonin make it less likely, and summation decides whether the threshold is crossed.
The function of the endocrine system: glands and hormones.
The endocrine system is the slow chemical partner to the nervous system: glands secrete hormones straight into the bloodstream, so the signal reaches every cell but only cells with matching receptors respond. It is slower to act than neural transmission but its effects are widespread and long lasting. The pituitary is the master gland, itself instructed by the hypothalamus; it releases ACTH, which drives the adrenal cortex to secrete cortisol during prolonged stress. The thyroid releases thyroxine, raising metabolic rate and heart rate; the adrenal medulla releases adrenaline; the ovaries release oestrogen and the testes testosterone. Evaluation is available here: the evidence linking testosterone to aggression in humans is largely correlational, and explaining behaviour by hormone level alone is reductionist, ignoring cognition and social context.
The fight or flight response including the role of adrenaline.
Faced with a threat, the amygdala signals the hypothalamus, activating the sympathetic branch of the autonomic nervous system. This stimulates the adrenal medulla to release adrenaline into the bloodstream, causing rapid physiological changes. Heart rate rises, breathing quickens, pupils dilate, and stored glycogen converts to glucose for muscle energy. Digestion is suppressed as it is not needed for immediate survival. Once the threat passes, the parasympathetic branch returns the body to baseline. For evaluation, Taylor et al. (2000) argued the model is beta biased as females often show a tend and befriend response, while Gray (1988) noted the initial reaction is usually to freeze and scan for information.
Localisation of function in the brain and hemispheric lateralisation: motor, somatosensory, visual, auditory and language centres; Broca’s and Wernicke’s areas, split brain research. Plasticity and functional recovery of the brain after trauma.
Localisation suggests specific functions reside in specific brain areas, while lateralisation means hemispheres have different roles. The motor cortex (frontal lobe) controls contralateral movement; the somatosensory cortex (parietal lobe) processes touch. The visual centre is occipital, and the auditory centre is temporal. Language is left-lateralised: Broca’s area damage causes non-fluent speech, whereas Wernicke’s area damage produces fluent but meaningless speech. Sperry’s split-brain research showed an image in the left visual field could not be named but could be identified by touch. The brain also shows plasticity and functional recovery after trauma, reorganising through mechanisms like axonal sprouting.
Ways of studying the brain: scanning techniques, including functional magnetic resonance imaging (fMRI); electroencephalogram (EEGs) and event-related potentials (ERPs); post-mortem examinations.
Each technique buys one thing and pays for it with another, and the marks come from that trade. fMRI does not measure neural activity directly; it measures blood flow, on the logic that active regions consume more oxygen, so it shows where activity happened to about a millimetre but lags several seconds behind the thought itself. EEG records the summed electrical activity of thousands of neurons through scalp electrodes, giving millisecond timing and the wave patterns used to diagnose epilepsy and to identify sleep stages, but it cannot say which structure produced a signal. ERPs are EEG recordings averaged over many repetitions of the same stimulus so that random background activity cancels out and the response to the event remains. Post-mortem examination links damage found after death to deficits recorded in life, as with Broca and Wernicke, but causation cannot be established.
Biological rhythms: circadian, infradian and ultradian and the difference between these rhythms. The effect of endogenous pacemakers and exogenous zeitgebers on the sleep/wake cycle.
Rhythms are sorted by how long one cycle takes. A circadian rhythm lasts about twenty-four hours, such as the sleep/wake cycle and the daily swing in core body temperature. An infradian rhythm takes longer than a day, such as the menstrual cycle of roughly twenty-eight days or seasonal affective disorder across a year. An ultradian rhythm is shorter than a day, such as the ninety-minute cycle through the stages of sleep into REM. Endogenous pacemakers are the internal clocks: the suprachiasmatic nucleus in the hypothalamus, which drives the pineal gland to release melatonin as light falls. Exogenous zeitgebers are external cues that reset it, chiefly light, plus social cues such as mealtimes. Siffre, isolated underground without clocks or daylight, free-ran on a cycle nearer twenty-five hours, showing the clock is internal but needs zeitgebers to stay in step.
Your focus
- Outline the divisions of the nervous system from CNS and PNS down to sympathetic and parasympathetic.
- Explain how the somatic and autonomic branches differ in voluntary control and in what they act on.
- Identify which division a described bodily response belongs to, such as a racing heart before a performance.
Show all 28 objectives
- Describe sensory, relay and motor neurons by location, direction of travel and dendrite and axon length.
- Explain synaptic transmission from action potential to vesicle release, diffusion across the cleft and receptor binding.
- Apply summation to decide whether a neuron receiving named excitatory and inhibitory inputs will fire.
- Explain why transmission at a synapse can run in only one direction.
- Describe how a hormone travels in the bloodstream and why only cells with matching receptors respond.
- Outline the pituitary as master gland and give two further gland and hormone pairs with their function.
- Explain how endocrine communication differs from neural transmission in speed, spread and duration.
- Evaluate hormonal explanations of behaviour, given correlational human evidence and the charge of reductionism.
- Describe the pathway from amygdala to hypothalamus to sympathetic branch to adrenal medulla and adrenaline.
- Explain three physiological changes in the response and give the survival reason for each.
- Apply the response to a described threat and say what the parasympathetic branch does once it has passed.
- Evaluate the model using Taylor on tend and befriend as beta bias and Gray on the freeze response.
- Describe the motor, somatosensory, visual and auditory centres by lobe and function, stating contralateral control.
- Explain how damage to Broca's area and to Wernicke's area produce different patterns of aphasia.
- Apply split brain findings to predict what a patient can name or pick out when an image goes to one visual field.
- Outline plasticity and functional recovery using Maguire's taxi drivers, axonal sprouting and homologous recruitment.
- Evaluate localisation using the tiny epileptic split brain samples and the plasticity evidence against fixed sites.
- Describe what fMRI, EEG, ERPs and post-mortem examination each actually measure.
- Compare fMRI and EEG on spatial and temporal resolution and explain why the trade runs that way.
- Apply the techniques to a described study by choosing the one that fits what the researcher needs to detect.
- Evaluate post-mortem examination, which cannot establish cause and raises consent problems after death.
- Distinguish circadian, infradian and ultradian rhythms by cycle length and give an example of each.
- Explain how the suprachiasmatic nucleus and melatonin from the pineal gland drive the sleep/wake cycle.
- Apply the pacemaker and zeitgeber distinction to Siffre's cave study to say why his cycle ran near 25 hours.
- Evaluate the isolation evidence, given single cases, small samples and artificial light acting as a zeitgeber.
Biopsychology exam tips
Marking Points
- CNS identified as brain and spinal cord, with the brain as the centre of conscious awareness and the spinal cord relaying messages and mediating reflexes.
- PNS defined as everything outside the brain and spinal cord, transmitting messages to and from the CNS.
- Somatic branch: voluntary, carries sensory input from receptors and motor output to skeletal muscle.
- Autonomic branch: involuntary, controls internal organs and glands, subdivided into sympathetic and parasympathetic.
- Sympathetic described as arousing (heart rate up, digestion suppressed) and parasympathetic as returning the body to baseline.
- An example from the stem correctly allocated to a named division.
- Sensory, relay and motor neurons each given their location, direction of travel and dendrite/axon length.
- Action potential described: resting negative charge, depolarisation by a stimulus, impulse along the axon to the terminal.
- Vesicles release neurotransmitter into the synaptic cleft and it diffuses across.
- Neurotransmitter binds to specific postsynaptic receptor sites and the chemical message becomes an electrical one again.
- Excitation defined as making the postsynaptic neuron more likely to fire, inhibition as making it less likely.
- Summation: the net effect of excitatory and inhibitory input determines whether the neuron fires.
- Reuptake or enzyme breakdown clears the cleft, and transmission is one-way because only the presynaptic terminal holds vesicles.
- Hormones defined as chemical messengers secreted by glands directly into the bloodstream.
- Only target cells carrying the right receptors respond, which is why a bloodstream signal has selective effects.
- Contrast with the nervous system: slower onset, but widespread and longer lasting effects.
- Pituitary named as the master gland, controlled by the hypothalamus, releasing hormones that direct other glands.
- At least two further gland/hormone pairs with a function, e.g. thyroid and thyroxine raising metabolic rate, adrenal medulla and adrenaline.
- Evaluation: correlational human evidence on hormones and behaviour, and the charge of biological reductionism.
- Amygdala appraises the threat and sends a distress signal to the hypothalamus.
- Hypothalamus activates the sympathetic branch of the autonomic nervous system (the sympathomedullary pathway).
- Adrenal medulla releases adrenaline directly into the bloodstream, which is why the response is almost immediate.
- At least three physiological effects with a survival reason: raised heart rate to deliver oxygen, glycogen to glucose for energy, dilated pupils, suppressed digestion.
- Parasympathetic branch restores resting state once the threat ends.
- Evaluation: Taylor et al. (2000) on tend and befriend and beta bias; Gray (1988) on the freeze response; chronic activation linked to raised blood pressure and heart disease in modern life.
- Motor cortex in the frontal lobe controlling voluntary movement, with contralateral control stated.
- Somatosensory cortex in the parietal lobe processing sensory information from the skin.
- Visual centre in the occipital lobe and auditory centre in the temporal lobe.
- Broca’s area in the left frontal lobe for speech production, with non-fluent aphasia as the evidence from damage.
- Wernicke’s area in the left temporal lobe for comprehension, with fluent but meaningless speech and neologisms.
- Split brain procedure and method: corpus callosum severed, stimulus presented to one visual field only, so information stays in one hemisphere.
- Plasticity: the brain reorganises with experience, e.g. Maguire et al. (2000) found more grey matter in the posterior hippocampus of London taxi drivers, correlated with time in the job.
- Functional recovery mechanisms named: axonal sprouting, recruitment of homologous areas in the other hemisphere, denervation supersensitivity.
- Evaluation: split brain samples were tiny and had epilepsy, so generalisation is limited; plasticity itself argues against rigid localisation.
- fMRI measures the haemodynamic response, oxygenated blood flow to active areas, rather than firing itself.
- fMRI strengths: non-invasive, no radiation, high spatial resolution; weaknesses: expensive, poor temporal resolution because of the delay.
- EEG measures general electrical activity via scalp electrodes and produces characteristic wave patterns.
- EEG strengths: very high temporal resolution, useful clinically for epilepsy and sleep research; weakness: poor spatial resolution and no localisation of the source.
- ERPs isolate the response to a specific stimulus by averaging many trials to remove extraneous activity.
- Post-mortem examination compares brain abnormality with behaviour observed in life, the basis of early localisation research.
- Post-mortem limitations: no causal conclusion, damage may result from decline or medication, and consent may not have been given before death.
- Circadian defined as roughly a twenty-four hour cycle, with the sleep/wake cycle or core body temperature as the example.
- Infradian defined as longer than twenty-four hours, with the menstrual cycle or seasonal affective disorder.
- Ultradian defined as shorter than twenty-four hours, with the stages of sleep and the roughly ninety-minute cycle.
- Endogenous pacemaker identified as the suprachiasmatic nucleus in the hypothalamus, receiving light information via the optic chiasm.
- Pineal gland and melatonin linked to darkness and the onset of sleepiness.
- Exogenous zeitgebers named, with light as the dominant cue and social cues such as mealtimes as secondary.
- Evidence used: cave and bunker isolation studies showing a free-running cycle of about twenty-five hours; animal research in which destroying the suprachiasmatic nucleus abolishes the sleep/wake rhythm.
- Evaluation: isolation studies rest on single cases and small samples, artificial light may itself have acted as a zeitgeber, and animal findings generalise to humans only with caution.
Examiner Tips
- 💡An 'outline the divisions' answer is best written top down: CNS, then PNS, then somatic and autonomic, then sympathetic and parasympathetic, with one sentence of function each.
- 💡In a scenario question, quote the bodily change described in the stem and label the division responsible for it, rather than describing the whole system again.
- 💡Match the breadth of the response to the command word by naming each relevant division and briefly explaining its distinct function.
- 💡Write synaptic transmission as an ordered sequence and keep the order: action potential, vesicles, cleft, receptors, new potential, reuptake. Examiners credit the chain, not a bag of terms.
- 💡An 'explain' question on excitation and inhibition wants the consequence for firing, so finish every sentence with 'more likely to fire' or 'less likely to fire'.
- 💡If the stem involves a drug, state which stage it acts on (release, binding or reuptake) and whether firing rises or falls as a result.
- 💡Answer gland questions as a triplet every time: gland, hormone, effect on the body. Three elements, one sentence.
- 💡If the question asks you to compare the endocrine and nervous systems, structure it by speed, route of travel and duration rather than writing two separate descriptions.
- 💡Scenario stems usually describe a bodily change; name the gland and hormone that produced it and avoid generic stress essays.
- 💡Learn the pathway as a chain of four links (amygdala, hypothalamus, sympathetic branch, adrenal medulla) so an outline writes itself.
- 💡Pair each physical change with its function; a list of changes reads as description while a change plus purpose reads as explanation.
- 💡In extended response questions, evaluation carries significant weight, so ensure concepts like tend and befriend, the freeze response, and the costs of chronic arousal are developed in depth rather than just listed.
- 💡Extended response questions require substantial evaluation, so plan two or three well-developed evaluation paragraphs (e.g., discussing plasticity or methodological limits of split-brain research) before writing your description.
- 💡Use case evidence precisely: name the researcher and what was found, because a named finding earns credit that a vague reference to research does not.
- 💡When evaluating localisation, set it against equipotentiality and plasticity rather than simply calling it reductionist.
- 💡In split brain answers, always state which visual field went to which hemisphere before describing the result, or the finding reads as a contradiction.
- 💡For each technique, state what it measures, how the result is produced, and a relevant strength and limitation.
- 💡When asked to compare, pick one dimension at a time (spatial resolution, temporal resolution, invasiveness) and run both techniques through it.
- 💡If the stem describes a study, match the technique to the research question: rapid processing needs EEG or ERPs, precise location needs fMRI.
- 💡Questions often ask for 'the difference between these rhythms', so define all three by cycle length first and only then give examples.
- 💡Every rhythm claim should carry evidence; naming the isolation study or the animal lesion research turns a description into a supported point.
- 💡For evaluation, attack the method rather than the conclusion: single case studies, small samples, uncontrolled artificial light and animal to human extrapolation.
Common Mistakes
- Placing the autonomic nervous system inside the CNS. It is a branch of the peripheral nervous system, even though its control centres sit in the brain.
- Saying the somatic system is sensory and the autonomic is motor. The somatic carries both sensory and motor pathways.
- Treating sympathetic and parasympathetic as separate systems rather than the two divisions of the autonomic branch.
- Drifting into hormones and glands, which belongs to the endocrine statement, and losing the neural detail the question asked for.
- Writing that the impulse 'jumps' or travels electrically across the synapse. Across the cleft the signal is chemical and moves by diffusion.
- Describing inhibition as 'stopping the message'. An inhibitory transmitter makes the postsynaptic membrane more negative, so firing is less likely, not impossible.
- Giving relay neurons long dendrites, which belongs to the sensory neuron.
- Naming transmitters without saying what they do; GABA earns nothing unless it is labelled inhibitory and linked to reduced firing.
- Saying hormones travel along neurons or through the nervous system. They travel in the blood.
- Confusing the adrenal cortex with the adrenal medulla, and so pairing cortisol with fight or flight instead of with prolonged stress.
- Listing glands without hormones, or hormones without effects; a bare list of gland names attracts almost no credit.
- Calling the hypothalamus a gland of the endocrine system only, and losing the point that it links the nervous and endocrine systems.
- Confusing adrenaline with cortisol. Adrenaline comes from the adrenal medulla in the acute response; cortisol comes from the adrenal cortex during prolonged stress.
- Describing the effects without saying why they help, when the adaptive reason is usually required for full explanation.
- Forgetting the parasympathetic 'rest and digest' return, so the answer implies arousal simply stops on its own.
- Writing the evaluation as 'it ignores women' instead of naming tend and befriend and identifying beta bias as the criticism.
- Swapping Broca’s and Wernicke’s symptoms. Broca’s damage leaves comprehension largely intact with halting speech; Wernicke’s leaves fluent speech that does not make sense.
- Saying the left hemisphere controls the left side of the body. Motor and visual processing are contralateral.
- Claiming split brain patients could not see the left visual field image at all; they processed it, but the right hemisphere has no language to report it.
- Treating plasticity as something only children have, when Maguire’s taxi drivers and studies of adult training show it continues through life.
- Describing functional recovery as damaged neurons growing back, rather than surviving circuits taking over the function.
- Saying fMRI shows neurons firing. It shows blood oxygen changes, which is an indirect measure.
- Confusing spatial and temporal resolution, then crediting EEG with pinpoint location or fMRI with instant timing.
- Treating ERPs as a separate machine rather than a way of analysing EEG data.
- Evaluating with one word (expensive, invasive) and not explaining what that costs the research conclusion.
- Reversing infradian and ultradian. Infra means below the frequency of a daily cycle, so the rhythm is longer; ultra means above it, so the rhythm is shorter.
- Calling the suprachiasmatic nucleus a zeitgeber. It is the internal pacemaker; light is the zeitgeber that entrains it.
- Saying the sleep/wake cycle is purely internal, when isolation studies show it drifts away from twenty-four hours without external cues.
- Using the menstrual cycle as an example of a circadian rhythm, or REM sleep as an infradian one.