Introduction to the Biological Approach

The biological approach assumes that everything psychological is, at root, physical. To 'think like a biological psychologist' is to ask: what is happening in the brain, the hormones, the genes or the evolutionary history that produces this behaviour? Nothing mental is treated as separate from the body — thoughts, moods and actions are products of biological machinery.

Assumption 1 — Behaviour, cognition and emotion can be explained in terms of the working of the brain and the effect of hormones, genetics and evolution.

• The brain controls behaviour — specific regions handle specific jobs (localisation of function), and the brain can physically change with experience (plasticity).
• Hormones are chemical messengers that influence behaviour (e.g. testosterone and play/aggression; oxytocin and social bonding; cortisol and stress).
• Genetics means some behaviours are inherited or have an innate, biological basis.
• Evolution means behaviours that aided survival and reproduction were naturally selected and passed on through generations.

Assumption 2 — Similarities and differences between people can be understood in terms of biological factors and their interaction with other factors.

• Why are males and females, or different individuals, alike or different? The biological approach looks first to biology — but the phrase "interaction with other factors" matters: even biological psychologists accept the environment plays a part. The approach is therefore not crudely deterministic.

Why the wording matters. A 2-mark "outline one assumption" question is pure recall — write the assumption and give a quick example, and you bank both marks.

Your textbook will teach the studies; this section gives you the underlying biology that makes the studies make sense. Understanding why a biological explanation works lets you write deeper, more confident answers — and explains the three core studies at a stroke.

1. Neurons and neurotransmitters. The brain is built from billions of nerve cells (neurons) that communicate using electrical impulses and chemical messengers called neurotransmitters (e.g. dopamine, serotonin) which cross tiny gaps (synapses). Brain activity — like the electrical patterns Dement & Kleitman recorded with an EEG — is the summed firing of huge numbers of neurons.

2. The brain and localisation of function. Different brain regions specialise in different jobs — this is localisation of function. For example, the hippocampus is central to memory and emotion, which is exactly why it appears in Hölzel's mindfulness findings.

3. The endocrine system and hormones. Glands release hormones into the blood; these are slower than neural signals but have widespread, lasting effects. Testosterone, an androgen, influences development and behaviour and is the leading explanation for the sex difference Hassett found in monkeys.

4. Genes and heredity. Genes carry inherited instructions. Behaviours with a genetic basis are part of the nature side of the debate; many biological rhythms (like the sleep cycle) are genetically programmed.

5. Evolution and natural selection. Behaviours that improved survival/reproduction were passed on. Sleep, sex differences in interests, and the brain's ability to adapt can all be given evolutionary explanations.

6. Brain plasticity. The brain can physically change its structure in response to experience. This is the headline of Hölzel's study and a beautiful example of nature and nurture interacting: the environment (meditation) reshapes biology (grey matter).

You will be examined on all three core studies, so build a one-line 'hook' for each — it makes recall under pressure far faster.

Study	Topic / 'psychology being investigated'	Headline finding
Dement & Kleitman (1957)	Sleep, dreaming, ultradian rhythms	Dreaming happens mostly in REM sleep; eye movements relate to dream content
Hassett et al. (2008)	Sex differences, hormones, play	Male monkeys prefer wheeled toys — sex differences in toy choice are partly biological, not just socialisation
Hölzel et al. (2011)	Mindfulness, localisation, brain plasticity	8 weeks of mindfulness increased grey matter (e.g. left hippocampus) — the brain physically changes with experience

How they fit the assumptions:

• Dement & Kleitman → the brain (EEG measures sleep stages) and an innate biological rhythm (the ~90-minute sleep cycle).
• Hassett et al. → hormones / evolution (toy preference linked to prenatal androgens, not learning).
• Hölzel et al. → the brain changing structure — neuroplasticity (biology shaped by experience).

Spot the pattern: all three use objective biological measurement (EEG/EOG, behavioural coding, MRI). This is a defining strength of the approach you can quote in evaluation.

Paper 1 questions often ask you to identify and evaluate the methodology of a core study. The biological studies between them showcase a wide range:

• Laboratory experiment — Dement & Kleitman (controlled sleep lab) and Hölzel et al. (MBSR group vs control group).
• Correlation — Dement & Kleitman (REM duration vs estimated dream length; eye-movement direction vs content) and Hölzel (practice time vs grey-matter change). Correlations show a relationship, not cause.
• Longitudinal design — Hölzel et al. (MRI before and after an 8-week course), allowing change over time to be tracked.
• Self-report / interview — Dement & Kleitman (dream reports) and Hölzel (the FFMQ mindfulness questionnaire).
• Observation with behavioural categories — Hassett et al. (coding toy interactions).
• Brain-scanning / objective measures — EEG and EOG (Dement & Kleitman); MRI (Hölzel).

Why this matters for A:* if a question says "evaluate the methodology used in [study]", the marks come from linking a feature to a strength or weakness (e.g. "MRI is an objective measure, so the data are not affected by researcher bias — increasing validity").

At AS Level you must relate each core study to the relevant issues and debates. The biological approach links most strongly to these:

• Nature vs nurture. Biology is the nature side. Hassett (hormones, not learning) and Dement & Kleitman (innate rhythm) support nature; Hölzel shows nurture (experience) altering biology — a great example of interaction.
• Use of animals in research. Hassett used 135 rhesus monkeys — discuss generalisability to humans and the ethics (cost–benefit).
• Use of children in research. Hassett compares its monkey data to human children data; consider why children's data is hard to interpret (the socialisation confound).
• Individual vs situational explanations. Biological factors are usually individual (within the person), e.g. an individual's hormones or brain structure — though Hölzel shows a situation (a course) changing the individual.
• Application to everyday life. Sleep clinics (Dement & Kleitman), mindfulness therapy & stress reduction (Hölzel), understanding the origins of gendered behaviour (Hassett).

Exam phrasing tip: when a question names an issue (e.g. "…at least one of your evaluation points must be about the use of animals"), you must include it or you cannot reach the top band.

Paper 1 (Approaches, Issues and Debates) is 1 hour 30 minutes, 60 marks, and tests AO1 (knowledge), AO2 (application) and AO3 (analysis/evaluation).

Section A — short-answer questions test recall of the core studies: aims, procedures, results, conclusions, and the issues/debates. Command words: state, outline, describe, identify, suggest, explain.

Section B — extended response & essay asks you to describe a study (~6 marks) and evaluate it (often 8–10 marks), and may compare studies.

The single most important exam skill — the 'evaluate' answer. From the Cambridge example responses, top answers must:

1. Give two strengths and two weaknesses (not a long list).
2. Include the named issue (e.g. generalisations, ethics) as at least one point.
3. Be in context — every point must use evidence from that study, not a generic statement.
4. Follow a logical chain (a 'PEEL' shape): Point → Explain what it means → Evidence from the study → Link to why it is a strength/weakness.

A point like "the sample was unrepresentative" scores low because it could apply to almost any study. "Hölzel only tested 16 right-handed adults, so the grey-matter findings may not generalise to left-handed people, who can use their brains differently" scores high — it is specific and explained.