Features of science | AQA A-Level Psychology Revision
- Revision Notes
- Aug 4
- 16 min read
Updated: 6 days ago
For 7182 specification, first teach in September 2025
AQA A-Level Psychology | Free Revision Notes
Estimated study time: 55 minutes
Scientific psychology aims to develop explanations using evidence that can be observed, measured, tested and checked by other researchers. This Features of science A-Level Psychology revision page explains objectivity, the empirical method, replicability, falsifiability, theory construction and hypothesis testing. These features help distinguish scientific conclusions from personal opinion or unsupported claims. Understanding how they work together will also prepare you for the next stage of research methods, where you will examine how established scientific thinking can change.
Learning Objectives 🎯
By the end of this revision page, you should be able to:
Define objectivity and the empirical method.
Explain how objectivity may be increased in psychological research.
Explain the meaning and importance of replicability.
Explain what makes a scientific claim falsifiable.
Distinguish a theory from a hypothesis.
Explain how theories are constructed, tested and refined using evidence.
Revision Notes 📚
Psychology as a science
Psychology investigates behaviour and mental processes. To be scientific, psychological explanations should be developed and tested using systematic procedures rather than being accepted because they sound convincing or match a researcher’s personal beliefs.
The scientific process involves:
Developing explanations.
Producing testable predictions.
Collecting empirical evidence.
Applying objective procedures.
Analysing findings.
Checking whether evidence supports the prediction.
Revising explanations where necessary.
Reporting procedures so that other researchers can repeat them.
The features covered in this lesson are closely connected. For example, a hypothesis must be falsifiable before it can be tested using empirical evidence, and a study must be described clearly before it can be replicated.
Objectivity
Objectivity means basing scientific decisions and conclusions on evidence rather than personal opinions, expectations or preferences.
An objective researcher attempts to:
Follow a planned procedure.
Record what happens accurately.
Apply the same rules to all participants.
Use clearly defined measurements.
Analyse the findings consistently.
Draw conclusions that are supported by the evidence.
Objectivity does not mean that researchers have no beliefs or expectations. It means that the investigation is designed to reduce the opportunity for these expectations to influence the procedure, data or conclusions.
Objectivity in psychological measurement
Psychologists often investigate concepts such as memory, concentration, stress or aggression. These concepts must be defined in a way that allows them to be measured consistently.
Compare these two measures:
“How good the participant’s memory appears to be.”
“The number of words correctly recalled from a list of 20 within two minutes.”
The second measure is more objective because it uses a clearly defined numerical score. The researcher has less freedom to decide personally whether a participant has a “good” memory.
This demonstrates why defining variables precisely is important within scientific research.
Objectivity in observations
Objectivity can be difficult when researchers observe complex behaviour.
A category such as:
Behaves aggressively
requires personal interpretation. Different observers may disagree about what counts as aggression.
More objective behavioural categories might include:
Hits another person.
Kicks another person.
Pushes another person with one or both hands.
These categories identify observable actions rather than relying on a general impression.
Objectivity may be increased further by:
Preparing categories before the observation.
Training observers.
Asking observers to record independently.
Comparing the records produced by different observers.
Revising categories where disagreement is high.
Objectivity in experiments
An experiment may become less objective if the investigator:
Gives some participants more help.
Changes the instructions between participants.
Allows different amounts of time.
Scores ambiguous responses according to expectations.
Treats one condition more positively than another.
Researchers can reduce these influences by using:
Standardised instructions.
Fixed time limits.
Consistent equipment.
Objective scoring systems.
Automated presentation or recording where appropriate.
Clear decision rules prepared before data collection.
These techniques form part of using procedures to reduce unwanted influences.
Objectivity and investigator effects
Investigator effects occur when a researcher’s behaviour, expectations or characteristics influence participants or the recording of data.
For example, a researcher who expects one group to perform better may:
Explain its task more carefully.
Give it more encouragement.
Allow borderline answers to receive marks.
Interpret unclear behaviour in a way that supports the expected result.
This weakens objectivity because the results may depend partly on the investigator’s expectations.
Standardised procedures, objective measurements and investigator training can reduce this influence. You can review these threats in participant and researcher influences on findings.
Objectivity and peer review
Objectivity is also supported when research is examined by other psychologists.
Peer reviewers may question:
The way variables were measured.
Whether conclusions follow from the data.
Whether alternative explanations were considered.
Whether the analysis was appropriate.
Whether personal judgement affected the interpretation.
This does not guarantee complete objectivity, but it exposes the researcher’s decisions to further scrutiny. This process is explored in expert assessment of psychological research.
The empirical method
The empirical method involves gaining knowledge through direct observation or measurement.
Empirical evidence is evidence collected through experience of the observable world rather than being based only on:
Personal belief.
Intuition.
Tradition.
Assumption.
An explanation that has not been tested.
Psychologists use empirical methods when they collect data through experiments, observations, questionnaires, interviews, correlations, content analyses or case studies.
The data may be numerical or descriptive. What makes the method empirical is that the evidence has been collected systematically rather than being accepted without investigation.
Examples of empirical evidence
Examples include:
The number of words recalled during a memory test.
The time taken to complete a puzzle.
The frequency of a behaviour recorded during an observation.
Responses given in a questionnaire.
Statements recorded during an interview.
Scores on two co-variables used in a correlation.
The observations or measurements should be recorded using a clear procedure so that the evidence can be analysed.
Empirical evidence and opinion
Consider the claim:
Background noise reduces concentration.
A personal opinion might be:
“I find noise distracting, so it must reduce everyone’s concentration.”
An empirical investigation might:
Create a condition in which participants work in silence.
Create a condition in which participants hear background noise.
Measure concentration using a defined task.
Compare the scores from the conditions.
Decide whether the findings support the prediction.
The empirical approach does not assume that the claim is correct. It collects evidence that could support or challenge it.
The importance of operationalisation
The empirical method requires variables to be observable or measurable.
A researcher cannot simply measure “concentration” without deciding what concentration will mean within the investigation.
It might be operationalised as:
Number of correct responses on an attention task.
Time taken to locate all targets in a visual-search task.
Number of errors made during a specified activity.
The operational definition determines exactly what evidence will be collected.
The importance of systematic data collection
Evidence should be collected through a planned and consistent method.
Suppose a researcher tests concentration but:
Gives some participants longer to complete the task.
Uses different instructions.
Changes the scoring rules.
Tests different conditions in very different environments.
The study still produces data, but the evidence may not provide a fair test of the research question.
Empirical research therefore requires more than collecting numbers or observations. The evidence must be gathered using an appropriate and controlled procedure.
Objectivity and the empirical method compared
Feature | Objectivity | Empirical method |
Main concern | Reducing the influence of personal opinion or expectation | Collecting knowledge through observation or measurement |
Main question | Were decisions based on consistent evidence rather than personal judgement? | Was the claim investigated using systematically collected data? |
Example | Applying the same scoring criteria to every participant | Recording each participant’s score on a memory task |
Possible improvement | Standardise procedures and use clear scoring rules | Operationalise variables and collect relevant evidence |
Relationship | Helps ensure evidence is recorded and interpreted consistently | Provides the evidence on which objective conclusions can be based |
A study may collect empirical data but still lack objectivity if the researcher records or interprets those data inconsistently.
Replicability
Replicability means that an investigation is described in enough detail for another researcher to repeat its procedures.
For a study to be replicable, the researcher should report information such as:
How participants were recruited.
The method and experimental design.
How variables were operationalised.
The materials and equipment used.
The instructions given.
The timing of each stage.
The controls used.
The way data were recorded and scored.
Another researcher should be able to follow the reported procedure rather than having to guess what happened.
Replicability and standardisation
A standardised procedure helps make research replicable because it states exactly how the investigation should be conducted.
For example, a replicable memory investigation might specify:
The exact list of words.
How long each word is displayed.
The instructions read to participants.
The length of the learning period.
The delay before recall.
The time allowed for recall.
The scoring criteria.
A description such as “participants learned some words and were later tested” would not contain enough detail for an accurate replication.
Why replication is important
Replication allows psychologists to investigate whether a finding is consistent.
If another researcher follows the procedure and obtains a similar pattern, confidence in the finding may increase.
Replication may also help reveal:
Missing procedural details.
Unclear operational definitions.
Measures that are difficult to use consistently.
Findings that depend on one particular sample or setting.
Results that do not occur when the investigation is repeated.
Replication therefore allows scientific findings to be checked rather than accepted permanently after a single investigation.
Replicability and reliability
Replicability and reliability are connected.
A replicable procedure can be repeated. The results of repetitions can then be compared to examine consistency.
However:
A procedure might be described clearly enough to replicate but still produce inconsistent results.
A reliable measure might produce consistent scores, but the research report may contain too little detail for another researcher to repeat the full procedure.
You should therefore distinguish whether a study can be repeated from whether its procedure and measurements are consistent.
Replicability and research reports
Clear scientific reporting is necessary for replication.
The method section should provide sufficient detail about:
Participants.
Design.
Materials.
Procedure.
Controls.
The results and discussion should explain what was found and how the findings were interpreted.
These sections are covered in communicating psychological investigations clearly.
Replication and different results
If a replication produces different findings, this does not automatically prove that the original study was worthless.
Researchers should check whether:
The procedure was followed accurately.
The participants differed.
The setting differed.
The materials were changed.
The original operational definitions were unclear.
The psychological effect is inconsistent.
The difference becomes further evidence that must be investigated.
Falsifiability
Falsifiability means that a scientific theory, explanation or claim must be capable of being tested and potentially shown to be incorrect by evidence.
A claim is falsifiable when it makes a prediction that could fail.
Falsifiability does not mean that the claim is false. It means that researchers can identify evidence that would count against it.
Example of a falsifiable prediction
Consider the hypothesis:
Participants who learn a list of words while background noise is played will recall fewer words than participants who learn the list in silence.
This prediction is falsifiable because:
The conditions are specified.
Recall can be measured.
The groups can be compared.
The predicted difference may or may not occur.
If participants in the noise condition do not recall fewer words, the findings would fail to support the prediction.
Example of a non-falsifiable claim
Consider the statement:
An undetectable force influences memory, but its effects cannot be observed or measured under any circumstances.
There is no possible observation that could show the claim to be incorrect. Any result could be explained by saying that the force was present but undetectable.
The claim is therefore not scientifically testable.
Features of a falsifiable claim
A falsifiable scientific claim should:
Be stated clearly.
Refer to variables that can be observed or measured.
Produce a testable prediction.
Allow a result that would count against the prediction.
Avoid explanations that can be adjusted to fit every possible outcome.
Operationalisation is important because vague variables make falsification difficult.
For example:
Positive environments improve people.
is difficult to test because “positive environments” and “improve” have not been defined.
A clearer claim would identify:
What counts as a positive environment.
What outcome is expected to change.
How that outcome will be measured.
Which groups or conditions will be compared.
Falsifiability does not require rejection
A theory may generate a prediction that is supported by evidence.
This does not make the prediction unfalsifiable. The important point is that a different possible result could have challenged it.
For example, a prediction that noise reduces recall remains falsifiable even if an investigation finds lower recall in the noise condition.
Falsifiability and scientific progress
Falsifiability allows theories to be challenged.
When evidence does not support a prediction, researchers may:
Check the method and measurement.
Conduct further research.
Revise the theory.
Limit the circumstances in which the theory is expected to apply.
Develop an alternative explanation.
Science develops because explanations remain open to testing rather than being protected from all possible criticism.
Replicability and falsifiability compared
Feature | Replicability | Falsifiability |
Main concern | Whether a procedure can be repeated | Whether a claim can potentially be shown incorrect |
Applies mainly to | The description of the investigation | The theory, explanation or prediction |
Requires | Clear procedural detail | A clear and testable claim |
Scientific contribution | Allows findings to be checked | Allows explanations to be challenged |
Example | Another researcher can repeat the same memory task | Evidence could show that the predicted memory difference does not occur |
What is a theory?
A theory is an organised explanation of behaviour or mental processes.
A theory aims to explain existing evidence and provide a basis for further research.
A useful scientific theory should generate predictions that can be tested empirically.
A theory is broader than a hypothesis. It may explain a general pattern, while a hypothesis predicts what should occur in a particular investigation.
What is a hypothesis?
A hypothesis is a clear, testable prediction about the expected outcome of an investigation.
In an experiment, it will normally predict a difference between conditions. In a correlation, it may predict a relationship between co-variables.
A hypothesis should:
Identify the relevant variables.
State the expected outcome clearly.
Be capable of empirical testing.
Be falsifiable.
Use operationalised variables where required.
The construction of directional and non-directional predictions is covered in writing research aims and hypotheses.
Theory and hypothesis compared
Theory | Hypothesis |
A broader explanation | A specific prediction |
Organises or explains findings | States an expected outcome |
May generate several hypotheses | Is tested in a particular investigation |
Can be developed over many studies | Refers to defined variables |
May be revised as evidence develops | May be supported or not supported by the findings |
Theory construction
Theory construction is the development of a scientific explanation using observations, previous findings and logical relationships between ideas.
A simplified process is:
A pattern or question is identified.
Evidence is collected.
An explanation is developed.
The explanation is organised into a theory.
The theory generates a testable hypothesis.
A study is designed to test the hypothesis.
Data are collected and analysed.
The findings are compared with the prediction.
The theory is supported, challenged or refined.
Further hypotheses are produced.
Theory construction is therefore not a one-off event. Scientific explanations develop as new evidence becomes available.
Hypothesis testing
Hypothesis testing involves collecting and analysing empirical evidence to determine whether it supports a stated prediction.
A researcher would:
Construct a testable hypothesis.
Operationalise the variables.
Select an appropriate research method.
Collect empirical data.
Analyse the data objectively.
Compare the findings with the prediction.
Decide whether the evidence supports the hypothesis.
Consider what the result means for the wider theory.
A single study may support or challenge a hypothesis, but the theory should also be considered alongside evidence from other investigations.
Worked example: theory construction and testing
A psychologist observes that some students appear to recall less information when they revise in noisy settings.
Stage 1: Develop an explanation
The psychologist proposes that background noise interferes with performance on a memory task.
Stage 2: Construct a hypothesis
Participants who learn a word list while café noise is played will recall fewer words than participants who learn the list in silence.
Stage 3: Operationalise the variables
Independent variable: learning while a recording of café noise is played compared with learning in silence.
Dependent variable: the number of words correctly recalled from a list of 20 within two minutes.
Stage 4: Collect empirical evidence
Participants complete the defined procedure and their recall scores are recorded.
Stage 5: Analyse the evidence
The researcher compares recall scores from the two conditions.
Stage 6: Consider the theory
If the predicted difference occurs, the findings provide support for the hypothesis.
If the predicted difference does not occur, the hypothesis is not supported by this investigation.
Further studies may be needed before the explanation is retained, revised or rejected.
Supporting evidence does not end testing
When evidence supports a hypothesis, psychologists may:
Replicate the investigation.
Test a different sample.
Change the setting.
Use a different operational definition.
Test another prediction from the theory.
Continued testing helps establish whether the finding is consistent and whether the explanation applies under different circumstances.
Findings that do not support the hypothesis
A finding that does not support a hypothesis is still scientifically useful.
It may show that:
The prediction was incorrect.
The theory requires revision.
The effect does not occur under the tested conditions.
The variables were not measured appropriately.
The procedure contained an important weakness.
A different explanation should be considered.
The researcher should not change the conclusion simply to make the original theory appear correct.
The relationship between theory and evidence
Scientific theories and empirical evidence influence each other.
Theories guide researchers towards questions and predictions.
Hypotheses convert theoretical ideas into testable statements.
Empirical investigations produce evidence.
Evidence is used to evaluate the hypothesis.
The combined findings may strengthen, limit or change the theory.
This creates an ongoing cycle rather than a straight line with a permanent final answer.
Features of science A-Level Psychology revision: the scientific cycle
Stage | Scientific feature involved |
Observe a pattern or identify a question | Empirical observation |
Develop an explanation | Theory construction |
Produce a specific prediction | Hypothesis construction |
Define the variables | Operationalisation |
Conduct the investigation | Empirical method |
Record and analyse data consistently | Objectivity |
Compare findings with the prediction | Hypothesis testing |
Identify evidence that challenges the claim | Falsifiability |
Report the procedure clearly | Replicability |
Allow experts and researchers to check the work | Peer review and replication |
Revise the explanation where necessary | Continued theory construction |
Applying features of science to an investigation
Consider the following scenario:
A researcher believes that green paper improves examination performance. Participants complete a test printed on either green or white paper. The researcher gives the green-paper group additional encouragement, does not state how answers will be scored and reports only that the green group “seemed more successful”.
Several scientific weaknesses are present.
Lack of objectivity
The researcher gives one group additional encouragement and uses an unclear judgement of success.
Weak empirical measurement
“Seemed more successful” is not a clearly defined measurement.
Limited replicability
The procedure and scoring rules are not described in sufficient detail.
Weak falsifiability
The claim has not been converted into a precise prediction using an operationalised measure of examination performance.
Improved procedure
The researcher should:
State a testable hypothesis.
Define the two paper conditions precisely.
Measure performance using a numerical test score.
Use the same instructions and encouragement.
Prepare scoring rules in advance.
Report the procedure fully.
Allow another researcher to repeat the investigation.
Evaluating whether a claim is scientific
Ask the following questions:
Is the claim stated clearly?
Can the variables be observed or measured?
Does the claim generate a testable hypothesis?
Could evidence potentially show the prediction to be incorrect?
Is evidence collected empirically?
Are procedures and measurements objective?
Is the method reported clearly enough to replicate?
Are conclusions based on the findings?
Could other researchers scrutinise and test the claim?
A claim does not become scientific simply because it uses technical language. It must be open to systematic testing.
Features of science within psychological research methods
These features connect with the full research process.
Designing research
Researchers construct aims and hypotheses, operationalise variables and select procedures that can provide an empirical test.
Conducting research
The procedure should be followed consistently and data should be recorded accurately.
Analysing research
Researchers should apply appropriate methods of analysis rather than selecting only findings that match their expectations.
Reporting research
Methods, findings and conclusions should be communicated clearly enough for scrutiny and replication.
These stages come together in planning a complete scientific investigation.
Key Words 🔑
Key word | Student-friendly definition | How it may be used in an exam |
Objectivity | Basing scientific decisions on evidence rather than personal opinion or expectation. | Explain how standardised procedures or objective scoring improve a study. |
Empirical method | Gaining knowledge through systematic observation or measurement. | Explain how a psychologist could collect evidence to test a claim. |
Empirical evidence | Data obtained through observation or measurement. | Distinguish scientific evidence from an unsupported opinion. |
Replicability | The extent to which a study is described clearly enough for another researcher to repeat it. | Explain why procedural detail must be reported. |
Replication | Repeating an investigation using the same or a closely comparable procedure. | Explain how a finding can be checked. |
Falsifiability | The requirement that a scientific claim can be tested and potentially shown to be incorrect. | Decide whether a claim is open to scientific testing. |
Theory | An organised explanation that accounts for evidence and generates predictions. | Explain how scientific ideas guide further research. |
Theory construction | Developing and refining an explanation using evidence. | Describe how findings may lead to a new or revised explanation. |
Hypothesis | A clear and testable prediction about the expected outcome of an investigation. | Construct or identify a prediction generated from a theory. |
Hypothesis testing | Collecting and analysing evidence to determine whether it supports a prediction. | Explain how data are used to assess a scientific claim. |
Operationalisation | Defining a variable precisely so it can be manipulated or measured. | Turn a theoretical idea into a testable variable. |
Standardisation | Keeping instructions, materials and procedures consistent. | Explain how objectivity and replicability can be improved. |
Evidence | Information used to support, challenge or refine a scientific explanation. | Explain how findings affect a theory. |
Scientific process | The continuing development, testing, checking and refinement of explanations. | Explain how the features of science work together. |
Common Mistakes ⚠️
Mistake: Defining objectivity as collecting numerical data.
Why this is incorrect:Numerical data may still be collected or interpreted inconsistently. Objectivity concerns reducing the influence of personal judgement and expectations.
How to improve:Refer to standardised procedures, clear measurements and conclusions based on evidence.
Mistake: Saying that empirical evidence must always come from a laboratory experiment.
Why this is incorrect:Empirical evidence may be collected using experiments, observations, self-reports, correlations, content analyses or case studies.
How to improve:Focus on whether the evidence was obtained systematically through observation or measurement.
Mistake: Confusing replicability with reliability.
Why this is incorrect:Replicability concerns whether another researcher can repeat the procedure. Reliability concerns whether the procedure or measure is consistent.
How to improve:Ask whether the problem is missing procedural detail or inconsistent results.
Mistake: Saying that replication means reading another researcher’s report.
Why this is incorrect:Replication involves repeating the investigation or procedure.
How to improve:Explain that the reported method is followed so that the findings can be compared.
Mistake: Saying that falsifiability means a theory is false.
Why this is incorrect:Falsifiability means that evidence could potentially show the theory or prediction to be incorrect.
How to improve:Explain what possible finding would count against the prediction.
Mistake: Treating a vague claim as falsifiable.
Why this is incorrect:If variables are not measurable or the claim can explain every possible result, it cannot receive a clear empirical test.
How to improve:Operationalise the variables and state the expected outcome.
Mistake: Using “theory” and “hypothesis” as interchangeable terms.
Why this is incorrect:A theory is a broader explanation. A hypothesis is a specific prediction generated from an explanation.
How to improve:State how the hypothesis would test one prediction from the theory.
Mistake: Saying that supporting evidence permanently proves a theory.
Why this is incorrect:Scientific explanations remain open to further testing, replication and challenge.
How to improve:State that evidence supports the prediction and may strengthen the theory.
Mistake: Ignoring findings that do not support the hypothesis.
Why this is incorrect:Unsupported predictions may reveal limitations, challenge the explanation or lead to further research.
How to improve:Explain how the theory or procedure might be reconsidered.
Mistake: Naming a scientific feature without applying it to the scenario.
Why this is incorrect:Application questions require you to explain which part of the procedure demonstrates or weakens the feature.
How to improve:Use details such as vague scoring, inconsistent instructions or missing procedural information.
Exam-Style Questions ✍️
Question 1
Define the empirical method. (2 marks)
Question 2
What is meant by objectivity in psychological research? (2 marks)
Question 3
Explain one way in which standardisation may increase objectivity. (2 marks)
Question 4
A psychologist reports that participants in one condition “appeared more motivated” but gives no explanation of how motivation was measured.
Explain why this measurement may lack objectivity. (3 marks)
Question 5
A researcher describes the aim, participants and results of an experiment but provides no details about the instructions, materials or timing.
Explain why the investigation may be difficult to replicate. (3 marks)
Question 6
Consider the following two statements:
Statement A: Participants who sleep for eight hours will identify more targets on a ten-minute attention task than participants who sleep for four hours.
Statement B: An invisible influence affects attention in a way that can never be observed or measured.
Identify which statement is falsifiable and explain your answer. (4 marks)
Question 7
Explain the difference between a psychological theory and a hypothesis. (4 marks)
Question 8
A psychologist develops the theory that background noise affects memory performance.
Explain how the psychologist could use hypothesis testing to investigate this theory. (6 marks)
Question 9
A researcher claims that a new task measures concentration. The researcher changes the instructions between participants, scores performance using personal judgement and provides too little procedural detail for another psychologist to repeat the study.
Explain how objectivity, operationalisation and replicability could be improved. (6 marks)
Question 10
Explain how objectivity, the empirical method, replicability, falsifiability, theory construction and hypothesis testing work together within the scientific process. (8 marks)
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