The Biological Approach

The biological approach argues that everything psychological is at first biological. To fully understand any behaviour, we must study the physical structures and processes that produce it: genes, the brain, the nervous system and neurochemistry.

This leads to a distinctive claim about where the mind sits. For the biological approach, the mind lives in the brain — all thoughts, feelings and behaviours ultimately have a physical, biological basis. This is a deliberate contrast with the cognitive approach, which treats the mind and the brain as separate, studying mental processes as software running on the brain's hardware.

Idea	Biological approach	Cognitive approach
Where is the mind?	The mind is brain activity	Mind and brain treated as separate
What should we study?	Genes, brain structures, neurochemistry	Internal mental processes and schema
Preferred methods	Scans, drug studies, twin and family studies	Lab experiments, inference from behaviour

The founding assumption to memorise: to understand behaviour we must look first at its physical bases — the genes we inherit and the biological structures and chemistry of the brain and nervous system.

Because it grounds behaviour in physical processes, the approach favours scientific, objective methods such as brain scans and controlled drug trials — a strength returned to in the evaluation.

The genetic basis of behaviour starts with two terms that are easy to confuse and are regularly tested.

• Genotype is a person's actual genetic make-up — the particular set of genes they inherit at conception.
• Phenotype is the observable characteristics of that individual, produced by the interaction of the genotype with the environment.

The key insight is that genotype alone does not fix the outcome. The environment acts on the genotype to produce the phenotype, so the same genotype can lead to different phenotypes.

Term	Definition	Example
Genotype	The genes an individual actually carries	Identical twins share the same genotype
Phenotype	Observable traits from genotype × environment	One twin who diets or trains ends up leaner or fitter

The classic illustration is monozygotic (identical) twins. They begin with the same genotype, yet differences in diet, exercise, upbringing and experience mean their phenotypes — height, weight, personality, even the expression of a disorder — are never perfectly identical.

Genotype is what you inherit; phenotype is what actually shows, once the environment has interacted with those genes. Because phenotype always involves the environment, the biological approach does not ignore nurture — it builds it into the definition.

If behaviour has a genetic basis, close relatives who share more genes should share more of the behaviour. Psychologists test this using twin studies, which compare concordance rates — the extent to which both twins share a characteristic — between two types of twin.

• Monozygotic (MZ) twins develop from one fertilised egg and share about 100% of their genes.
• Dizygotic (DZ) twins develop from two separate eggs and share about 50% of their genes, like ordinary siblings.

The logic is a comparison. If a behaviour is influenced by genes, the concordance rate should be higher in MZ twins than in DZ twins, because MZ twins are more genetically alike.

Twin type	Genes shared	Concordance if trait is genetic
Monozygotic (MZ)	~100%	Higher
Dizygotic (DZ)	~50%	Lower

Worked interpretation. Suppose a study reports a concordance rate for a disorder of 68% in MZ twins and 31% in DZ twins. Because the MZ rate is much higher, this suggests a genetic component to the disorder. But note the MZ figure is not 100% — if genes were the whole story, every MZ pair would be concordant. The shortfall shows the environment also contributes.

A raised MZ concordance rate suggests genes matter, but a concordance below 100% for MZ twins is itself evidence that behaviour is not determined by genes alone.

The genetic basis of behaviour extends across generations through evolution. The biological approach draws on Darwin's theory of natural selection to explain why certain behaviours are widespread in a species.

The reasoning runs in steps:

1. Genes vary between individuals, and some genetically influenced traits or behaviours improve an organism's chances of surviving and reproducing.
2. Individuals with those advantageous traits are more likely to live long enough to reproduce.
3. They pass the underlying genes to their offspring.
4. Over many generations the advantageous behaviour becomes more common in the population — it has been naturally selected.

So any genetically determined behaviour that enhances survival and reproduction will tend to be selected for and passed on. Behaviours that reduce survival or reproductive success tend to be selected against and become rarer.

Natural selection is the mechanism: behaviours are selected not because they are "good" in a moral sense, but simply because they helped ancestors survive and reproduce, so the genes behind them were passed down.

An often-cited example is an innate readiness to form attachments: an infant who stays close to a caregiver is more likely to be protected, survive and eventually reproduce, so a genetic basis for attachment behaviour would be favoured by natural selection.

Behaviour also depends on the physical structures of the brain and nervous system and on their neurochemistry — the balance of chemicals that carry signals within the brain.

Neurones communicate at synapses using chemical messengers called neurotransmitters. The biological approach argues that the levels and activity of these neurotransmitters directly influence behaviour and mental states, so an imbalance can be linked to a psychological disorder.

Neurotransmitter	Typical influence	Linked disorder (imbalance)
Serotonin	Mood regulation, impulse control	Low levels linked to depression and OCD
Dopamine	Reward, movement, motivation	Abnormal levels linked to schizophrenia

For example, low levels of serotonin are associated with depression and with OCD. Alongside neurochemistry, specific brain structures are tied to specific functions — a link explored directly by cognitive neuroscience in the next slide.

The neurochemical claim is testable and clinically useful: if low serotonin contributes to depression, then drugs that raise serotonin activity should relieve symptoms — the basis of many modern treatments.

This mechanistic view is a genuine strength, because it produces predictions that can be tested with drugs and scans rather than left as abstract theory.

Cognitive neuroscience is the scientific study of how brain structures and processes influence mental processes. In the current AQA 7182 specification it sits under the biological approach (having moved here from the cognitive approach), so it is required content in this topic.

It emerged as a distinct field as brain-scanning techniques became powerful and precise. Using scans such as fMRI (which tracks blood flow to map active regions) and PET, researchers can watch the living brain at work and map mental functions onto specific brain areas.

Technique	What it measures	What it lets researchers do
fMRI	Changes in blood flow / oxygen use	See which regions activate during a task
PET	Metabolic activity via a radioactive tracer	Locate areas involved in a mental process

The idea of tying mental functions to brain regions is older than the scanners. In the 1860s Broca linked speech production to a specific area of the left frontal lobe (now Broca's area) after studying patients who lost fluent speech. Modern cognitive neuroscience builds on that principle, using scans to map processes such as memory and decision-making onto particular structures.

Cognitive neuroscience is the modern bridge between biology and cognition: it takes mental processes, once studied only by inference, and locates them physically in the brain using objective scanning evidence.

An A-level answer needs developed AO3 points, not just description. Each point below states the criticism or strength and explains its effect.

Strength — scientific, objective methods. The approach relies on brain scans, drug trials and twin studies, methods that are precise, replicable and objective. This gives its explanations high scientific credibility and places psychology alongside the natural sciences, which is a clear strength compared with approaches that rely on subjective interpretation.

Strength — real-world application. Understanding neurochemistry has led directly to psychoactive drug treatments. For example, discovering the role of serotonin in depression supported the development of SSRIs, which help many people manage mental illness and can allow them to live relatively normal lives. This practical value is a major strength of the approach.

Limitation — biological determinism and reductionism. The approach can be reductionist, explaining complex behaviour purely in terms of genes or neurotransmitter levels and so downplaying the roles of environment, cognition and free will. Viewing behaviour as biologically determined also raises problems, for instance for the legal system, which assumes people freely choose their actions.

Limitation — separating nature from nurture is difficult. Twin studies are confounded because MZ twins usually share their environment as well as their genes, so a high concordance rate cannot be attributed to genetics alone. The genotype–phenotype distinction makes the same point: because phenotype always reflects the environment, the approach cannot cleanly isolate the genetic contribution to behaviour.

Evaluation point	Type	Core idea
Scientific methods	Strength	Objective, replicable, credible
Real-world drug treatments	Strength	Neurochemistry → SSRIs and other therapies
Determinism / reductionism	Limitation	Oversimplifies; downplays environment and choice
Nature vs nurture confound	Limitation	Twins share environments; phenotype includes it

1. Confusing genotype and phenotype

Genotype is the genetic make-up you inherit; phenotype is the observable result of that genotype interacting with the environment. Students who swap these definitions lose easy marks. Remember that identical twins share a genotype but never have a perfectly identical phenotype.

2. Forgetting cognitive neuroscience is part of the biological approach

In the current AQA 7182 specification, cognitive neuroscience is listed under the biological approach, not the cognitive approach. An answer on the biological approach that omits it has left out required content.

3. Treating high MZ concordance as proof of a 100% genetic cause

A raised MZ concordance rate suggests a genetic component, not a purely genetic cause. If genes were the whole explanation, MZ concordance would be 100%. A figure below that is evidence the environment also plays a part.

4. Saying the biological approach ignores the environment

The definition of phenotype builds the environment in: phenotype comes from genotype interacting with the environment. Claiming the approach ignores nurture misrepresents it. The sharper criticism is that it reduces behaviour to biology and struggles to separate nature from nurture, not that it ignores the environment entirely.

5. Describing evaluation instead of evaluating

Naming a criticism such as "reductionism" is not enough. State the point, then explain its consequence — for example, that reducing behaviour to neurochemistry downplays cognition, environment and free will, which limits the completeness of the explanation.