Non-Experimental Methods

Not all psychological research uses experiments. When it is not possible or appropriate to manipulate an IV, psychologists use non-experimental methods to study behaviour. These methods are valuable for exploring, describing, and understanding behaviour, but they cannot establish cause-and-effect relationships.

flowchart TD
    A[Non-Experimental Methods] --> B[Observations]
    A --> C[Self-report]
    A --> D[Case studies]
    A --> E[Correlations]
    B --> B1[Naturalistic / Controlled]
    B --> B2[Participant / Non-participant]
    B --> B3[Overt / Covert]
    C --> C1[Questionnaires]
    C --> C2[Interviews: structured / semi / unstructured]
    E --> E1[Positive]
    E --> E2[Negative]
    E --> E3[No correlation]

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1. Observations

An observation involves watching and recording behaviour as it occurs, either in a natural setting or a controlled environment.

Types of Observation

Type	Description	Example
Naturalistic	Observing behaviour in its natural setting without interference	Watching children play in a playground
Controlled	Observing behaviour in a structured, controlled environment	Watching children play in a laboratory playroom
Participant	The researcher joins the group being observed	A researcher joining a gang to study behaviour
Non-participant	The researcher watches from outside without joining	Watching through a one-way mirror
Overt	Participants know they are being observed	Announced classroom observation
Covert	Participants do not know they are being observed	Hidden camera observation

Evaluation

Strength	Weakness
High ecological validity (especially naturalistic)	Observer bias — different observers may interpret behaviour differently
Can study behaviour that cannot be ethically manipulated	Cannot establish cause and effect
Can capture natural, spontaneous behaviour	Participants may change behaviour if they know they are observed (Hawthorne effect)

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2. Questionnaires (Self-Report)

A questionnaire is a set of written questions used to gather information about a person's thoughts, feelings, attitudes, or behaviours.

Types of Questions

Type	Description	Advantage	Disadvantage
Closed questions	Fixed response options (e.g. Yes/No, rating scales)	Easy to analyse quantitatively	May not capture the full picture
Open questions	Respondents write their own answers	Provide rich, detailed data	Difficult to analyse and compare

Evaluation

Strength	Weakness
Can collect data from large samples quickly and cheaply	Social desirability bias — respondents may give answers they think are acceptable rather than truthful
Easy to replicate (standardised questions)	Questions may be misunderstood or interpreted differently by different people
Can be anonymous, encouraging honest responses	Response bias — some people tend to always agree (acquiescence bias)

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3. Interviews

An interview involves the researcher asking questions verbally (face-to-face or by phone/video).

Types of Interview

Type	Description	Strength	Weakness
Structured	Fixed questions asked in a set order	Easy to replicate and compare responses	Inflexible — cannot follow up interesting responses
Unstructured	No fixed questions — develops like a conversation	Flexible — can explore topics in depth	Difficult to replicate and analyse
Semi-structured	Some fixed questions but freedom to follow up	Combines structure with flexibility	Still partly subjective in analysis

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4. Case Studies

A case study is an in-depth investigation of a single person, group, event, or organisation. Case studies typically use multiple methods (observations, interviews, tests, medical records) to build a detailed picture.

Examples: The case of HM (memory), Clive Wearing (memory), Phineas Gage (brain damage)

Strength	Weakness
Provides rich, detailed data about unique cases	Cannot generalise from a single case to the wider population
Can study phenomena that are rare or unethical to create experimentally	Researcher bias — the researcher may interpret data subjectively
Can generate hypotheses for future research	Relies on retrospective data (e.g. medical records), which may be incomplete

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5. Correlations

A correlation is a statistical technique that measures the relationship between two variables. It tells us whether two variables are related and in what direction, but it does not tell us that one variable causes the other.

Types of Correlation

Type	Description	Example
Positive correlation	As one variable increases, the other also increases	More hours of revision → higher exam scores
Negative correlation	As one variable increases, the other decreases	More hours of screen time → lower exam scores
No correlation	No relationship between the variables	Shoe size and exam scores

Evaluation

Strength	Weakness
Can identify relationships between variables	Cannot establish cause and effect — correlation does not equal causation
Can be used when it is unethical to experiment	A third variable may explain the relationship
Can be used to generate hypotheses for experimental research	Can be misleading if the relationship is assumed to be causal

Exam Tip: Always remember: "Correlation does not equal causation." A positive correlation between ice cream sales and drowning does not mean ice cream causes drowning — both are caused by a third variable (hot weather).

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Key Points

• Non-experimental methods include observations, questionnaires, interviews, case studies, and correlations.
• These methods are valuable for exploring behaviour but cannot establish cause and effect.
• Each method has specific strengths and weaknesses that you should be able to describe and evaluate.
• Correlations show relationships between variables but do not prove causation.

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Quick Reference: Strengths and Weaknesses at a Glance