Research Methods: Experimental and Non-Experimental

What you'll learn

This guide covers all research methods required for WJEC GCSE Psychology, including experimental designs (laboratory, field, and natural experiments) and non-experimental methods (observations, self-reports, and case studies). You'll understand how psychologists gather data, control variables, and choose appropriate methods for different research questions. Mastering these concepts is essential as research methods questions appear throughout the exam and are worth significant marks.

Key terms and definitions

Independent Variable (IV) — the variable that the researcher deliberately manipulates or changes to observe its effect on behaviour.

Dependent Variable (DV) — the variable that is measured by the researcher; the outcome that may change as a result of the IV.

Extraneous variables — unwanted variables that could affect the DV if not controlled, potentially confusing the results.

Operationalisation — defining variables in a clear, measurable way so they can be accurately tested and replicated.

Ecological validity — the extent to which research findings can be generalised to real-life settings and situations.

Participant observation — a research method where the researcher becomes part of the group being studied, experiencing events from the participants' perspective.

Informed consent — an ethical requirement where participants agree to take part in research after being told what the study involves.

Reliability — the consistency of a research method; whether it produces similar results when repeated under the same conditions.

Core concepts

Laboratory experiments

Laboratory experiments take place in a controlled environment where the researcher manipulates the IV and measures the DV whilst controlling extraneous variables. The psychologist creates artificial conditions specifically for the research.

Strengths:

• High control over extraneous variables means cause-and-effect relationships can be established
• Standardised procedures make the experiment easy to replicate, testing reliability
• Specialist equipment can be used for precise measurements

Weaknesses:

• Artificial settings may cause participants to behave unnaturally (low ecological validity)
• Participants may show demand characteristics, trying to guess the experiment's purpose
• Findings may not generalise to real-world situations

Example: Bandura's Bobo doll experiment tested aggression in a controlled laboratory setting, manipulating whether children saw aggressive or non-aggressive adult models.

Field experiments

Field experiments occur in natural, everyday environments (like schools, workplaces, or streets) where the researcher still manipulates the IV but participants are in their normal setting.

Strengths:

• Higher ecological validity than laboratory experiments because behaviour occurs in natural contexts
• Participants may be unaware they're being studied, reducing demand characteristics
• Results are more generalisable to real-life situations

Weaknesses:

• Less control over extraneous variables (weather, noise, interruptions)
• Harder to replicate exactly due to changing natural conditions
• Ethical issues if participants don't know they're in a study (lack of informed consent)

Example: A researcher might test memory techniques by teaching one class using rhymes and another using repetition, then comparing test scores in their normal classroom environment.

Natural experiments

Natural experiments involve IVs that occur naturally or are changed by someone other than the researcher. The psychologist simply measures the DV and compares groups.

Strengths:

• Allows research into variables that cannot be manipulated for ethical reasons
• High ecological validity as the IV would have occurred anyway
• Useful for studying rare phenomena or unique situations

Weaknesses:

• Cannot randomly allocate participants to conditions, limiting control
• Extraneous variables are difficult to control
• Cannot establish clear cause-and-effect relationships
• May be impossible to replicate the natural event

Example: Comparing stress levels in students before and after national exam reforms (the researcher didn't introduce the reforms but studies their effects).

Observations

Observations involve watching and recording behaviour systematically. They can be structured (using predetermined categories) or unstructured (recording everything seen).

Types of observations:

Naturalistic observation — watching behaviour in the environment where it normally occurs without interference.

• High ecological validity but low control over extraneous variables
• Example: Observing playground behaviour to study social interaction in children

Controlled observation — watching behaviour in a structured environment created by the researcher.

• More control but potentially artificial behaviour
• Example: Observing parent-child interaction through a one-way mirror in a research room

Participant observation — the researcher joins the group being studied.

• Gains insider perspective but may lose objectivity
• Example: A researcher joining a sports team to study motivation

Non-participant observation — the researcher remains separate from those being observed.

• Maintains objectivity but may miss subtle behaviours
• Example: Recording aggressive incidents in a school canteen from a distance

Strengths of observations:

• Records actual behaviour rather than what people say they do
• Useful when participants cannot express themselves verbally (young children, animals)
• Can generate hypotheses for future research

Weaknesses of observations:

• Observer bias — researchers might interpret behaviour according to their expectations
• Inter-observer reliability issues if different observers record different things
• Ethical concerns about privacy and consent, especially in naturalistic settings
• Cannot establish cause and effect

Self-report methods

Self-report methods gather data directly from participants about their thoughts, feelings, or behaviours through questionnaires and interviews.

Questionnaires use written questions with either closed questions (fixed responses like yes/no or rating scales) or open questions (free responses in participants' own words).

Strengths:

• Can gather large amounts of data quickly and cheaply
• Respondents may feel comfortable disclosing sensitive information anonymously
• Closed questions produce quantitative data that's easy to analyse

Weaknesses:

• Social desirability bias — people answer in ways that make them look good
• Leading questions may influence responses
• People may not understand questions or may misremember information
• Low response rates for postal questionnaires

Interviews involve direct verbal questioning, either structured (predetermined questions in fixed order), unstructured (informal conversation around general topics), or semi-structured (combination of both).

Strengths:

• Can explore complex issues in depth, especially with open questions
• Interviewer can clarify misunderstood questions
• Can gather detailed qualitative data about experiences and motivations

Weaknesses:

• Time-consuming and expensive to conduct
• Interviewer bias may influence responses
• Difficult to replicate as each interview may differ
• Social desirability bias when answering face-to-face

Case studies

Case studies involve detailed, in-depth investigation of a single individual, group, or event using multiple research methods (observations, interviews, tests, document analysis).

Strengths:

• Rich, detailed data about unique or rare cases
• Can study situations that couldn't be created ethically in experiments
• Generates hypotheses for future research
• Holistic understanding of the individual in their context

Weaknesses:

• Findings cannot be generalised to other people due to small sample size
• Researcher bias in selecting and interpreting information
• Relies on retrospective data which may be inaccurate
• Time-consuming and expensive to conduct

Example: HM (Henry Molaison) was studied extensively after brain surgery left him unable to form new memories, providing crucial insights into memory processes that couldn't be obtained ethically through experimentation.

Variables and controls

Operationalisation is crucial in psychological research. Variables must be defined precisely so they can be measured objectively.

Poorly operationalised: "Does stress affect memory?" Well operationalised: "Do students who experience examination anxiety (scoring above 15 on the Test Anxiety Inventory) recall fewer words from a 20-item list than students scoring below 10?"

Extraneous variables must be controlled to ensure they don't confuse results:

Participant variables — differences between individuals (age, gender, intelligence, mood)

• Control through random allocation to conditions or matched pairs design

Situational variables — features of the environment (temperature, noise, lighting, time of day)

• Control by standardising the procedure and keeping conditions constant

Experimenter variables — influence of the researcher (expectations, instructions, appearance)

• Control through standardised instructions and double-blind procedures where neither participant nor researcher knows the condition

Ethical considerations

All psychological research must follow ethical guidelines:

Informed consent — participants must understand what participation involves before agreeing. For children, parental consent is required.

Deception — misleading participants should be avoided, but if necessary for valid results, participants must be debriefed afterwards.

Right to withdraw — participants can leave the study at any time without giving a reason or facing consequences.

Confidentiality — personal information must be kept private; data should be anonymous where possible.

Protection from harm — participants shouldn't experience physical or psychological distress beyond everyday life.

Debriefing — after the study, participants should be informed of the true aims and allowed to ask questions.

Worked examples

Example 1: Identifying variables (2 marks)

Question: A psychologist investigates whether listening to music affects concentration. Students complete a puzzle either in silence or whilst listening to classical music. The time taken to complete the puzzle is recorded.

Identify the independent variable and the dependent variable in this study.

Mark scheme answer:

• Independent Variable: Whether students listen to music or sit in silence / presence or absence of classical music (1 mark)
• Dependent Variable: Time taken to complete the puzzle (1 mark)

Examiner note: You must clearly identify both variables. Vague answers like "the music" or "concentration" wouldn't receive full marks because they aren't specific enough.

Example 2: Evaluating a research method (4 marks)

Question: A researcher uses a questionnaire to investigate teenagers' attitudes towards social media. Give two strengths and two weaknesses of using a questionnaire for this research.

Mark scheme answer:

Strengths (1 mark each):

• Questionnaires can gather data from a large number of teenagers quickly and cheaply, making the research more efficient
• Teenagers may answer more honestly about sensitive social media issues if the questionnaire is anonymous, reducing social desirability bias

Weaknesses (1 mark each):

• Teenagers may not understand certain questions about social media, leading to invalid responses
• Social desirability bias may occur if teenagers want to appear responsible in their social media use, affecting the truthfulness of responses

Examiner note: Each point needs development/explanation for the full mark. Simply stating "quick" or "anonymous" without explaining why this matters wouldn't receive the mark.

Example 3: Designing an observation (6 marks)

Question: A psychologist wants to observe helping behaviour in children aged 5-7 years during school playtime. Explain how the psychologist could conduct a naturalistic observation to investigate this behaviour. In your answer, refer to where the observation would take place and how behaviour would be recorded.

Mark scheme answer:

The psychologist should observe children in their normal playground environment during regular break times (1 mark), ensuring they don't interfere with or change the natural setting (1 mark).

Before observing, they should operationalise "helping behaviour" by creating specific, observable categories such as "sharing toys," "comforting an upset child," or "helping someone who has fallen" (1 mark for operationalisation).

They could use a structured observation approach with a behaviour checklist or tally chart to record each time a helping behaviour occurs (1 mark for recording method). Using two observers who record independently would allow them to check inter-observer reliability (1 mark).

The psychologist should obtain informed consent from parents and the school before conducting the observation (1 mark for ethical consideration).

Examiner note: This 6-mark question requires detailed application to the specific scenario. Generic observation answers that don't reference children, playgrounds, or helping behaviour specifically would lose marks.

Common mistakes and how to avoid them

• Confusing IV and DV: Remember that the IV is what the researcher changes or compares; the DV is what they measure. A simple check: "Does [IV] affect [DV]?" must make logical sense.

• Writing vague evaluations: Don't just say "high ecological validity" or "can't generalise." Explain why in the context of the specific study (e.g., "laboratory settings are artificial, so participants may not behave naturally, reducing ecological validity").

• Failing to operationalise variables: In exam questions asking you to design a study, always define variables in measurable terms. "Aggression" needs to become "number of hits on a Bobo doll" or "instances of verbal insults recorded."

• Mixing up observation types: Naturalistic means the natural environment with no manipulation; controlled means some structure is imposed. Participant/non-participant refers to whether the researcher joins the group, not the location.

• Forgetting ethical issues: When describing or evaluating any study, consider at least one ethical guideline. "The researcher should obtain informed consent from participants" shows good psychological understanding.

• Not applying knowledge to scenarios: In longer questions, generic textbook answers score poorly. Always refer specifically to the scenario given — mention the actual variables, participants, or setting described in the question.

Exam technique for "Research Methods: Experimental and Non-Experimental"

• Command words matter: "Identify" requires a brief, accurate label (1 mark). "Explain" needs a point plus development (2 marks). "Evaluate" requires strengths/weaknesses with reasoning (2-3 marks each). "Discuss" needs balanced analysis with a conclusion.

• Mark allocations guide detail: For 1 mark, a single accurate point suffices. For 2 marks, give a point plus explanation or two distinct points. For 4-6 marks, expect to provide multiple developed points applied to the specific context.

• Use the PEEL structure for longer answers: Point (make your argument), Evidence (provide an example or detail), Explain (say why this matters), Link (connect back to the question). This ensures developed, high-scoring responses.

• Practice identifying research methods: Exam questions frequently describe a study and ask you to identify the method or variables. Practice spotting whether the IV was manipulated (experiment) or just observed (non-experimental), and whether it's in a natural or controlled setting.

Quick revision summary

Research methods split into experimental (lab, field, natural) and non-experimental (observations, self-reports, case studies). Experiments manipulate IVs to measure effects on DVs, with laboratory offering high control but low ecological validity. Field and natural experiments increase realism but reduce control. Observations record actual behaviour but risk observer bias. Self-reports gather participants' views but suffer from social desirability bias. Case studies provide rich detail about individuals but can't be generalised. Always operationalise variables clearly, control extraneous variables, and consider ethical guidelines including informed consent, right to withdraw, and confidentiality.