All subjects · Psychology · WPS04 Clinical Psychology and Psychological Skills

Additional methods: twins, animals, case studies, scanning, RCTs and more

Edexcel IAL Psychology · WPS04 Clinical Psychology and Psychological Skills

Spec 9.1.9 lists additional methods from across the course: twin studies, animal experiments, case studies (including brain-damaged patients), brain scanning, RCTs, content analysis, clinical interviewing, ethnography, longitudinal and cross-sectional research, cross-cultural research and meta-analysis.

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Methods from Units 1, 2 and 4

Method	What it is	Course example	Key evaluation
Twin studies	Compare MZ and DZ concordance	Brendgen et al. (2005) aggression; Gottesman and Shields (1966)	Shared environment confounds genes
Animal experiments	Controlled studies on animals	Pavlov, Skinner (1948)	Control and ethics; generalising to humans
Case studies	In-depth study of one person or small group	HM (memory); Freud's Little Hans	Rich detail; not generalisable; subjective
Brain scanning	CAT, PET, fMRI	Raine et al. (1997) PET	Objective; correlational
RCTs	Random allocation to treatment or control	DeRubeis et al. (2005)	Cause and effect; ethics of controls
Content analysis	Coding media or documents	Clinical practical	Unobtrusive; subjective coding

Methods from development (Topic E)

Clinical interviewing: flexible, child-centred questioning to explore thinking (as used by Piaget).
Ethnographic fieldwork: researchers immerse themselves in a community. Punch (2002) studied 37 children aged 8 to 14 in rural Bolivia, combining participant observation and interviews with task-based methods (drawings, photographs, diaries, worksheets), arguing for 'research-friendly' rather than 'child-friendly' methods.
Longitudinal: the same people studied over time (shows development, but slow and suffers drop-out). Cross-sectional: different age groups compared at one time (quick, but cohort differences).
Cross-cultural research: comparing cultures, for example the Strange Situation across countries.
Meta-analysis: combining results of many studies. Van IJzendoorn and Kroonenberg (1988) combined 32 Strange Situation samples from 8 countries (1,990 infants); Hans and Hiller (2013) combined 34 CBT studies.

Evaluating meta-analysis and cross-cultural research

Meta-analysis: large combined samples increase generalisability and show overall patterns; but studies vary in quality and method, and publication bias means non-significant studies may be missing.
Cross-cultural research: tests whether findings are universal; but tools developed in one culture (such as the Strange Situation, developed in the USA) may not mean the same elsewhere (ethnocentrism), and samples may not represent whole cultures: Van IJzendoorn and Kroonenberg found variation within countries was about 1.5 times greater than variation between them.

Worked example

Explain why Becker et al. (2002) is cross-sectional rather than longitudinal, and why this matters.

Longitudinal research follows the same people over time; Becker surveyed different girls in 1995 and 1998.
So Becker is cross-sectional (repeated with new samples).
This matters because changes could reflect differences between the two groups of girls rather than change caused by TV within individuals.

Answer: Different samples mean individual change cannot be shown.

Key idea: Additional methods: twin, animal, case study, scanning, RCT, content analysis, clinical interviewing, ethnography (Punch, 2002), longitudinal vs cross-sectional, cross-cultural (Strange Situation), meta-analysis (Van IJzendoorn and Kroonenberg, 1988; Hans and Hiller, 2013). Give a course example and an evaluation for each.

Check yourself

A study follows the same children from age 3 to age 13. This is
- a cross-sectional study
- a meta-analysis
- an RCT
- a longitudinal study
Show answer
a longitudinal study. Same people over time.
What is a meta-analysis?
- A study of one person in depth
- A statistical combination of the results of many studies
- An observation of children in their community
- A brain scan
Show answer
A statistical combination of the results of many studies. Combining studies.
Van IJzendoorn and Kroonenberg (1988) combined 32 samples with 1,990 infants. What was the mean sample size? Give your answer to 1 decimal place.
Show answer
62.2. 1,990 / 32 = 62.2.
Which is a feature of ethnographic fieldwork?
- The researcher spends extended time immersed in a community
- Participants are randomly allocated
- Data come only from brain scans
- It always uses a laboratory
Show answer
The researcher spends extended time immersed in a community. Immersion in a community.
Punch (2002) studied children aged 8 to 14. What is the age range?
Show answer
6 years. 14 - 8 = 6 years.
Why are case studies such as HM hard to generalise from?
- They study one unusual individual in depth
- They use very large samples
- They only use animals
- They are always laboratory experiments
Show answer
They study one unusual individual in depth. One unique person.
Explain one problem with cross-cultural research such as Strange Situation studies.
Show answer
The Strange Situation was developed in the USA, so behaviours such as distress at separation may mean something different in other cultures, making the comparison ethnocentric and less valid.. Imposed etic / ethnocentrism or unrepresentative samples.

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Last updated 8 November 2026. Spotted a mistake? Tell us.