Biological approach

Using an animal to study a process that also happens in humans, because of shared biology.

Shared biology, tighter control, testing risky methods safely first, and faster life cycles.

To apply a result from one group (the animals) to another (humans) — done with caution.

Animals and humans share a lot but also differ, so a result may not fully transfer.

Replacement (use another method), Reduction (fewer animals), Refinement (less suffering).

Using a non-animal method instead of animals wherever possible, such as computer or cell studies.

Using as few animals as possible while still getting clear results.

Changing how animals are treated to reduce any pain or suffering.

Weighing the harm a study causes animals against the good it may do, before it is allowed.

Responsibility — researchers have power over the animals and must protect their welfare.

It allows tightly controlled studies and lets risky methods be tested safely before humans.

Animals can suffer and cannot give consent, so the harm may not always be justified.

Explaining something complex by breaking it down into simpler parts.

Explaining behaviour using its simplest biological parts — brain areas, chemicals and genes.

Explaining behaviour by looking at the whole person and their situation, including thoughts, environment and culture.

Explaining it only by low activity of a neurotransmitter and treating it with a medicine.

It is precise and testable — a small biological question can be measured, which has led to real treatments.

It can oversimplify by ignoring thoughts, environment and culture, so one cause rarely explains a whole behaviour.

Perspective — it is one way of looking at behaviour, raising whether a single perspective is ever enough.

Because it can treat behaviour as fixed by biology, reducing the sense of choice.

A smaller, biological question is easier to measure and test than a big, messy one.

Reductionism: explain by the simplest parts. Holism: explain by the whole person and situation.

Not wrong — useful and precise, but often incomplete on its own.

When combined with a more holistic view, so precision and the bigger picture work together.

Techniques that show the structure or activity of the living brain, such as fMRI, EEG and PET.

Blood flow to show which brain areas are active — good spatial detail (where).

Electrical activity via the scalp — excellent timing (when), poor location.

A radioactive tracer to map activity or chemicals; shows function but is invasive.

fMRI is strong on location, weak on timing; EEG is the reverse.

Objective, measurable data on the living brain, often non-invasive.

It shows activity correlated with a task, not that the area caused the behaviour.

Lying still in a noisy scanner is artificial and unlike real-life behaviour.

No — it shows correlation; reverse or third-variable explanations still apply.

Measurement — it makes invisible brain activity measurable.

A chemical the brain or body uses to carry a signal that affects behaviour — a neurotransmitter or a hormone.

A chemical that carries a signal across the synapse (gap) between two nerve cells.

A chemical messenger carried in the blood to affect the body; slower but longer-lasting than a neurotransmitter.

The tiny gap between two nerve cells that a neurotransmitter crosses.

A part of a cell that a chemical messenger fits into, like a key in a lock, to pass on the signal.

It is released, crosses the synapse, and fits a receptor on the next cell; left-over is cleared by reuptake.

Dopamine — released in the reward pathway, giving pleasure and making a behaviour more likely to repeat.

Causality — a chemical is linked to a behaviour, but a link is not proof that it causes the behaviour.

The two occur together, but the behaviour could cause the chemical change, or a third factor could cause both.

Indirectly — e.g. by giving a drug that changes its level and watching behaviour, or by brain imaging.

It is precise and testable, and has led to real treatments such as medicines for low mood.

Behaviour usually involves many chemicals, and a link is often only a correlation, not proof of cause.

A disorder results from a vulnerability (diathesis) combined with environmental stress (a trigger).

A predisposition or vulnerability — genes, brain chemistry, early experience — that raises risk.

A triggering life event or ongoing strain that can tip a vulnerable person over.

The interaction — stress exceeding what the person's vulnerability can withstand.

Their vulnerabilities differ, so the stress crosses the threshold for some but not others.

Less — high vulnerability can be triggered by only mild stress.

It combines nature and nurture, avoiding a one-sided explanation.

Vulnerability is hard to measure and the threshold for 'enough' stress is vague.

No — without enough stress, the disorder may never appear.

Causality — the cause is an interaction of vulnerability and stress.

The idea that some behaviour is passed down in our genes, not only learned from the environment.

A section of DNA that carries instructions passed from parents to children.

An inherited tendency that makes a behaviour or condition more likely — not certain.

How often both twins share a trait — used to compare identical and non-identical twins.

If identical twins (who share ~all genes) share a trait more than non-identical twins (~half), genes probably matter.

How much of the difference in a trait across people is linked to genes. It is almost never 100%.

Genes and environment working together — an inherited tendency may only appear if life events trigger it.

Causality — a trait can run in families, but genes, shared environment, or both could cause it.

Families share both genes AND an environment, so the pattern does not prove genes are the cause.

Twin and family studies give a clear way to estimate a genetic influence and explain traits that run in families.

Identical twins usually share an environment too, so genes and environment are hard to separate; a link is not proof of cause.

They compare children with their biological and adoptive families, helping separate genes from upbringing.

The idea that specific brain areas carry out specific jobs or behaviours.

Damage to a part of the brain — often used as evidence for what that area does.

If damage to a specific area is followed by the loss of a specific ability, that area was probably needed for it.

A scan can show which area becomes active during a task, pointing to where the job is done.

Producing fluent speech; damage can leave a person unable to speak fluently while still understanding others.

Causality — damage-then-loss suggests an area is needed for an ability, but activity alone is not proof of cause.

Brain damage and imaging give clear, testable links between an area and a function.

Many behaviours use several areas together, so functions are often shared, not fixed to one spot.

Because other areas can sometimes take over a job, so a function is not permanently fixed to one area.

They are often one patient, so the finding may not generalise to everyone.

E.g. occipital lobe — vision; motor cortex — movement; amygdala — emotion/fear.

No — it shows the area is active and likely involved, not that it alone causes the behaviour.

The brain's ability to change and reorganise — connections grow and strengthen with experience, or reroute after damage.

When connections that are used repeatedly become stronger and faster.

Removing connections that are rarely used — 'use it or lose it'.

Practising fires the same connections again and again, so they strengthen and the skill becomes automatic.

Healthy areas can slowly take over some jobs of a damaged area, so lost abilities can partly return.

Change — behaviour and the brain change together through experience, rather than being fixed.

Brain imaging can show real, physical changes after practice, and it explains recovery after injury.

It is hard to prove practice alone caused the change, since many life factors change at once.

Plasticity tends to slow with age, so change is not equally easy for everyone.

No — rewiring can also strengthen unhelpful habits, so change is not always positive.

Connections you use are strengthened; connections you don't use are pruned away.

No — imaging shows that a change occurred, not exactly what caused it.

How neurons pass signals using electrical impulses and chemical messengers across a synapse.

Impulse fires, neurotransmitters release, bind to receptors, then are cleared (reuptake/breakdown).

The tiny gap between two neurons that neurotransmitters cross.

A site on the receiving neuron where a matching neurotransmitter binds.

Leftover neurotransmitter being taken back into the sending neuron, resetting the synapse.

By blocking reuptake, so a neurotransmitter stays active in the synapse longer.

Within = electrical impulse; between = chemical neurotransmitters.

Precise, evidence-based, and explains how many medicines work.

It can be reductionist and ignores thoughts, environment and social context.

Causality — chemical signals are a physical cause of behaviour.