The Scientific Process and Research Methods Revision

This final lesson covers the scientific process in psychology and provides a comprehensive revision of all research methods concepts for the AQA GCSE Psychology exam.

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The Scientific Process

Psychology aims to be a science. This means it follows the scientific process — a systematic approach to investigating the world:

Steps of the Scientific Process

1. Observation — noticing a pattern or phenomenon that needs explaining
2. Hypothesis — formulating a testable prediction based on existing theory
3. Research design — planning a study to test the hypothesis (choosing methods, sampling, etc.)
4. Data collection — carrying out the study and gathering data
5. Data analysis — using statistical methods to examine the data
6. Conclusion — interpreting the results and deciding whether the hypothesis is supported
7. Peer review — submitting findings for evaluation by other experts
8. Publication — sharing findings with the scientific community
9. Replication — other researchers repeat the study to check the findings

This process is cyclical — new findings lead to new questions, which lead to new hypotheses and further research.

flowchart LR
    A[Observation] --> B[Hypothesis]
    B --> C[Research design]
    C --> D[Data collection]
    D --> E[Data analysis]
    E --> F[Conclusion]
    F --> G[Peer review]
    G --> H[Publication]
    H --> I[Replication]
    I --> A

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Key Features of the Scientific Method

Objectivity

Research should be objective — free from personal bias or subjective judgement. This is achieved through:

• Standardised procedures — the same steps are followed each time
• Operationalised variables — clear, measurable definitions
• Statistical analysis — using mathematics rather than personal opinion

Falsifiability

A hypothesis must be falsifiable — it must be possible to design a study that could disprove it. If a theory cannot be tested or disproved, it is not scientific.

Example: "Invisible unicorns cause all mental illness" is not falsifiable (you cannot prove invisible unicorns do not exist), so it is not a scientific hypothesis.

Replicability

Good research should be replicable — other researchers should be able to repeat the study using the same procedures and get the same results. If a study cannot be replicated, its findings are not reliable.

Empiricism

Science is empirical — it is based on observable, measurable evidence rather than on personal belief, opinion, or speculation.

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Research Methods: Complete Summary

Method	IV Manipulated?	Cause & Effect?	Ecological Validity	Control
Lab experiment	Yes	Strong	Low	High
Field experiment	Yes	Moderate	High	Moderate
Natural experiment	No	Weak	High	Low
Quasi-experiment	No	Weak	Variable	Low
Observation	No	No	High (naturalistic)	Low
Questionnaire	No	No	Variable	Moderate
Interview	No	No	Variable	Variable
Case study	No	No	High	Low
Correlation	No	No	Variable	N/A

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Common Exam Mistakes to Avoid

1. Confusing correlation with causation — a correlation shows a relationship, NOT that one variable causes the other
2. Confusing random sampling with random allocation — sampling = selecting participants; allocation = assigning to conditions
3. Confusing reliability and validity — reliability = consistency; validity = accuracy
4. Not operationalising variables — always define the IV and DV in measurable terms
5. Forgetting to mention both advantages AND disadvantages when evaluating a method
6. Confusing independent groups and repeated measures — independent = different participants; repeated = same participants

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Applying Research Methods to Scenarios

When given a scenario in the exam, use this checklist:

Question	What to Identify
"What is the IV?"	What is being changed/manipulated between conditions?
"What is the DV?"	What is being measured?
"What design is used?"	Independent groups, repeated measures, or matched pairs?
"What type of experiment?"	Lab, field, natural, or quasi?
"What sampling method?"	Random, opportunity, stratified, or systematic?
"Identify an extraneous variable"	What other factor could affect the DV?
"Is this ethical?"	Consider consent, deception, harm, withdrawal, confidentiality

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Key Definitions Quick Reference

Term	Definition
Hypothesis	A testable prediction about the outcome of a study
IV	Variable manipulated by the researcher
DV	Variable measured by the researcher
Extraneous variable	Variable that could affect the DV if not controlled
Confounding variable	Extraneous variable that has systematically varied with the IV
Random allocation	Randomly assigning participants to conditions
Counterbalancing	Varying the order of conditions to reduce order effects
Demand characteristics	Cues that reveal the study's aim, causing participants to change behaviour
Ecological validity	Whether findings apply to real-life settings
Reliability	Consistency of a measurement
Validity	Whether a study measures what it claims to measure
Peer review	Evaluation of research by independent experts before publication

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Revision Checklist

• I can formulate directional and non-directional hypotheses
• I can explain the three experimental designs and their strengths/weaknesses
• I can identify IV, DV, and extraneous/confounding variables
• I can describe the four sampling methods
• I can explain lab, field, natural, and quasi experiments
• I can describe observations, questionnaires, interviews, case studies, and correlations
• I can explain the BPS ethical guidelines
• I can calculate mean, median, mode, and range
• I can explain reliability and validity (types and threats)
• I can describe the scientific process and peer review