AQA Syllabus focus:
'The biological approach: biological structures, neurochemistry and cognitive neuroscience.'
This section explains how the biological approach links behavior and cognition to brain structures, chemical signaling, and modern methods that connect mental processes to measurable neural activity.
Biological structures
The biological approach argues that behavior and mental life can be explained through the body’s physical systems. Rather than separating thoughts, emotions, and actions from biology, it examines how the brain, nervous system, and endocrine system make behavior possible.
The nervous system
A major biological structure is the nervous system, which allows rapid communication around the body. It is divided into two main parts:
Labeled overview of the human nervous system, showing the central nervous system (brain and spinal cord) alongside major peripheral nerves. This helps you map the CNS/PNS distinction onto concrete anatomical structures and see how the PNS spreads throughout the body. Source
The central nervous system (CNS) consists of the brain and spinal cord. It receives information, processes it, and directs responses.
The peripheral nervous system (PNS) carries messages between the CNS and the rest of the body.
The PNS can be divided further:
The somatic nervous system controls voluntary movement by sending signals to skeletal muscles.
The autonomic nervous system (ANS) controls involuntary processes such as heart rate and digestion.
The ANS has two branches:
The sympathetic division increases arousal and prepares the body for action, such as in a threat situation.
The parasympathetic division reduces arousal and returns the body to a resting state.
These structures are important because changes in activity in different parts of the nervous system can alter attention, emotion, and behavior.
The endocrine system
The endocrine system is another key biological structure. It is made up of glands that release hormones directly into the bloodstream. Hormones act more slowly than nerve impulses, but their effects often last longer.
Important glands include:
The pituitary gland, often called the “master gland,” because it influences other glands
The adrenal glands, which release hormones such as adrenaline
The thyroid gland, which affects metabolism and energy levels
The endocrine system works closely with the nervous system. For example, in a stressful situation, the brain can trigger the adrenal glands to release adrenaline, increasing alertness and preparing the body for action.
Brain structures and behavior
The brain itself contains specialized structures linked to different functions. The biological approach assumes that behavior is shaped by activity in these areas.
Examples include:
The frontal lobe, involved in decision-making, planning, and voluntary movement
The temporal lobe, associated with hearing, language, and aspects of memory
The occipital lobe, mainly responsible for visual processing
The parietal lobe, important in sensory processing and spatial awareness
Subcortical structures are also significant:
The hippocampus is strongly linked to memory formation
The amygdala is involved in emotional processing, especially fear and threat
This focus on physical structures supports the idea that behavior has a material basis in the brain.
Neurochemistry
Neurochemistry refers to the chemical processes that allow the nervous system to function. In the biological approach, behavior is influenced not only by brain structures, but also by the neurotransmitters and hormones that affect communication within and between those structures.
Neurotransmitters are chemical messengers released at synapses.
Diagram of chemical synaptic transmission showing neurotransmitter release from presynaptic vesicles, diffusion across the synaptic cleft, receptor binding on the postsynaptic neuron, and reuptake. This is a compact visual summary of the key steps that underpin how excitatory vs inhibitory effects emerge from synaptic signaling. Source
They can have excitatory effects, making a neuron more likely to fire, or inhibitory effects, making firing less likely. Because of this, neurochemistry influences mood, motivation, learning, attention, and many other aspects of behavior.
Important neurotransmitters include:
Dopamine, linked to reward, motivation, and movement
Serotonin, associated with mood and emotional regulation
GABA, an inhibitory neurotransmitter involved in calming neural activity
Acetylcholine, important in attention and memory
The biological approach suggests that behavior may be affected by imbalances in these chemicals, by differences in receptor sensitivity, or by changes in how quickly neurotransmitters are reabsorbed or broken down. This helps explain why drugs that alter neurotransmitter activity can also change behavior and mental states.
Hormones are also part of neurochemistry. For instance, cortisol is associated with stress responses, and abnormal hormone levels can influence energy, mood, and concentration. This shows that biological explanations often involve both structures and chemicals working together.
Cognitive neuroscience
Cognitive neuroscience studies how mental processes are linked to activity in the brain. It combines the cognitive approach, which focuses on internal mental processes such as memory and attention, with the biological approach, which examines the brain and nervous system.
This area asks questions such as:
Which brain areas are active during memory tasks?
How does the brain process language?
What neural activity is associated with decision-making or attention?
Methods used in cognitive neuroscience
Cognitive neuroscience depends heavily on brain-imaging and recording techniques:
fMRI measures changes in blood oxygenation, showing which brain areas are more active during a task
EEG records electrical activity in the brain, making it useful for studying the timing of mental processes
ERPs are specific patterns within EEG data that are linked to particular events or stimuli
Example event-related potential (ERP) waveform with common components labeled (including N1/N100 and P3/P300). This illustrates how ERP research identifies reliable, time-locked voltage deflections that can be linked to specific perceptual and cognitive processing stages. Source
These methods allow researchers to compare brain activity while a person is thinking, remembering, reading, or responding to emotional information.
Why cognitive neuroscience matters
Cognitive neuroscience has made it possible to identify neural correlates of mental processes. A neural correlate is a pattern of brain activity associated with a particular behavior or cognitive function. This has improved understanding of how memory, language, perception, and attention operate in the living brain.
It has also helped psychologists compare typical brain functioning with patterns seen after brain injury or in neurological conditions. By doing this, researchers can refine explanations of how cognition works and which structures are involved.
An important feature of cognitive neuroscience is that it treats mental processes as real but measurable through biological activity. Instead of relying only on behavior or self-report, it uses physical evidence from the brain itself to investigate how the mind works.
Practice Questions
Outline two functions of the autonomic nervous system. (2 marks)
1 mark for stating that it controls involuntary bodily processes, such as heart rate or digestion.
1 mark for stating that it includes the sympathetic division, which increases arousal, or the parasympathetic division, which reduces arousal.
Credit any other valid function or feature.
Explain how cognitive neuroscience has contributed to the understanding of human behavior. (6 marks)
1 mark for explaining that cognitive neuroscience combines the study of mental processes with the study of brain activity.
1 mark for reference to techniques such as fMRI, EEG, or ERPs.
1 mark for explaining that these methods identify brain activity linked to specific cognitive functions.
1 mark for linking this to behaviors such as memory, attention, language, or decision-making.
1 mark for explaining that it helps identify neural correlates of behavior.
1 mark for explaining that it improves or refines explanations of behavior by providing biological evidence.
Credit clear, accurate elaboration throughout.
FAQ
A neural correlate is a pattern of brain activity that appears alongside a mental process or behavior.
It does not automatically prove causation because:
the activity may happen at the same time without producing the behavior
another brain area may actually drive the process
the correlation could reflect the result of the behavior rather than its cause
To show causation, researchers usually need converging evidence, such as brain injury data, stimulation studies, or repeated findings across different methods.
An agonist increases the effect of a neurotransmitter. It may:
mimic the neurotransmitter
increase its release
block its reuptake
An antagonist reduces the effect of a neurotransmitter. It may:
block receptor sites
reduce release
interfere with synthesis
These effects matter because they show that changes in brain chemistry can alter mood, perception, memory, and motivation. This is one reason drug research is important in biological psychology.
A neurotransmitter does not have one fixed effect everywhere.
Its effect depends on:
the type of receptor it binds to
the brain region involved
whether the target neuron is excitatory or inhibitory
how much of the neurotransmitter is present
For example, the same chemical messenger may increase activity in one circuit but reduce it in another. This is why simple statements like “one neurotransmitter causes one behavior” are usually too reductionist.
Resting-state scans measure brain activity when a person is not doing a specific task.
They are useful because they can show:
how different brain regions communicate as networks
stable patterns of functional connectivity
differences between typical and atypical brain organization
This matters in cognitive neuroscience because many mental abilities depend on coordinated networks rather than one isolated brain area. Resting-state research helps psychologists understand the brain’s baseline organization.
Several practical issues can reduce accuracy or generalizability:
Cost: fMRI and similar methods are expensive.
Artificial settings: lying still in a scanner may not reflect everyday thinking.
Small samples: studies often use limited numbers of participants.
Movement artifacts: even slight movement can distort data.
Complex analysis: results depend on how the data are processed and interpreted.
Because of these issues, findings are usually strongest when different methods point to the same conclusion.
