Post-event discussion and eyewitness testimony | AQA A-Level Psychology Revision
Updated: Sep 9
For 7182 specification, first teach in September 2025
AQA A-Level Psychology | Free Revision Notes
Estimated study time: 40 minutes
These Post-event discussion and eyewitness testimony A-Level Psychology revision notes explain how witnesses can influence one another after observing the same event. Details introduced during a conversation may become mixed with a witness’s original memory, reducing the accuracy of their later account. You will examine memory conformity, source-monitoring errors and research into co-witness discussion. This lesson develops your understanding of how misleading questions affect witness reports while showing why information from another witness creates a different form of memory distortion.
Learning Objectives 🎯
By the end of this revision page, you should be able to:
Define post-event discussion.
Explain how witnesses can contaminate one another’s accounts.
Explain memory conformity.
Explain source-monitoring errors.
Distinguish post-event discussion from leading questions.
Evaluate research into post-event discussion.
Revision Notes đź“š
Post-event discussion and eyewitness testimony A-Level Psychology revision overview
Post-event discussion occurs when witnesses discuss an event after it has happened.
During the conversation, one witness may introduce details that another witness:
Did not observe.
Did not remember.
Interpreted differently.
Believed were absent.
Was uncertain about.
The second witness may later include these details in their own account.
This can produce memory contamination, in which information received after the event becomes mixed with the witness’s original memory.
Post-event discussion may therefore reduce the accuracy of eyewitness testimony, or EWT.
What is eyewitness testimony?
Eyewitness testimony is an account provided by someone who has witnessed an event.
A witness may be asked to recall:
The people present.
What each person did.
The appearance of a suspect.
Objects seen at the scene.
The sequence of events.
What was said.
The location of important details.
Eyewitness testimony can be valuable, but it is not a perfect recording.
The account may be influenced by information received after the event, including:
Leading questions.
Discussion with co-witnesses.
Media reports.
Comments from investigators.
Information provided by friends or relatives.
What is misleading information?
Misleading information is incorrect or suggestive information presented after an event.
Two forms named in the AQA specification are:
Leading questions.
Post-event discussion.
Both occur after the witness has observed the event, but the source of the information is different.
In leading questions, misleading information is introduced through the wording of a question.
In post-event discussion, misleading information is introduced through another person’s account.
A basic example of post-event discussion
Two witnesses observe a robbery.
Witness A sees the offender leave through the front door.
Witness B cannot see the exit but later hears Witness A say:
“The offender ran out through the front door.”
When questioned separately, Witness B reports seeing the offender leave through the front door.
Witness B’s account may have been contaminated because:
They did not originally observe the exit.
They received the information during the discussion.
They later included the detail in their own testimony.
The witness may not be deliberately lying. They may genuinely believe that the detail came from their own observation.
How post-event discussion affects memory
Memory contamination
Memory contamination occurs when information received after an event becomes mixed with the original memory.
The likely process is:
A witness observes an event.
The witness forms an initial memory.
They discuss the event with another person.
The other person introduces additional or conflicting information.
The witness becomes uncertain about the original event.
The new information becomes incorporated into their account.
Their later testimony becomes less accurate.
The contamination may involve:
Adding a detail that was absent.
Removing an original detail.
Changing the sequence of events.
Replacing one object with another.
Adopting another witness’s interpretation.
Co-witnesses
A co-witness is another person who observed the same event.
Co-witnesses do not necessarily see exactly the same thing.
They may have:
Different viewing positions.
Different levels of attention.
Different distances from the event.
Different visual obstructions.
Different expectations.
Different emotional reactions.
One witness may therefore have access to a detail that another witness could not see.
Problems arise when the witnesses later discuss their experiences and become uncertain
about which details they observed personally.
Why eyewitness accounts may become similar
After discussion, witnesses’ accounts may become more alike.
This is called memory conformity.
Witnesses may agree because:
They believe the other person has a better memory.
They think the other person had a clearer view.
They want to avoid disagreement.
They assume agreement means greater accuracy.
They confuse the other person’s information with their own observation.
Similar accounts do not necessarily prove that the accounts are correct.
Several witnesses may give the same inaccurate detail because one person introduced it during discussion.
Memory conformity
What is memory conformity?
Memory conformity occurs when one person’s account of an event influences another person’s reported memory.
The witness conforms to information supplied by someone else.
For example, two witnesses disagree about the colour of a vehicle.
Witness A confidently says that the vehicle was blue. Witness B originally thought it was green but later reports that it was blue.
Witness B may have conformed to Witness A’s account.
Social approval
A witness may copy another person’s account to avoid disagreement or gain social approval.
This is similar to normative social influence because the individual changes their public response to fit with another person.
The witness may think:
“I do not want to appear difficult.”
“They seem very confident.”
“It will be embarrassing if I am wrong.”
“Everyone else remembers it differently.”
This form of memory conformity may alter the witness’s report without necessarily changing the underlying memory.
It connects with the desire to gain approval and avoid rejection.
Believing the other witness is correct
A witness may also accept another account because they believe the other person has more accurate information.
This is more likely when:
The witness is uncertain.
The event occurred quickly.
The other witness appears confident.
The other witness had a better viewing position.
The other witness claims to remember the event clearly.
The individual may use the other witness as a source of information.
The change may therefore reflect a genuine belief that the other account is correct.
Public conformity and private acceptance
Memory conformity could involve different levels of change.
Public conformity
The witness reports the other person’s version to avoid disagreement but privately remains uncertain or disagrees.
Their underlying memory may not have changed.
Private acceptance
The witness comes to believe that the other person’s version is accurate.
The misleading detail may become part of their reconstructed memory.
It can be difficult for researchers to determine whether a changed answer reflects public conformity or genuine memory distortion.
Source monitoring
What is source monitoring?
Source monitoring is the process of identifying where a memory came from.
A person may remember a detail but need to decide whether it came from:
Their own observation.
Another witness.
A question.
A photograph.
A news report.
Their imagination.
General knowledge.
A source-monitoring error occurs when the person remembers the information but confuses its origin.
Source confusion
After discussing an event, a witness may remember a detail without remembering that another person supplied it.
For example:
The witness remembers a red bag.
They cannot remember whether they saw it or heard another witness mention it.
They decide that it must have been part of the original event.
They report seeing the bag.
The error concerns the source of the detail rather than whether the detail feels familiar.
How source-monitoring errors develop
The process can be summarised as:
A witness observes an event.
They later hear a co-witness describe an additional detail.
The additional detail becomes familiar.
The witness forgets that the detail came from the discussion.
They attribute it to their own observation.
The detail appears in their eyewitness account.
Familiarity is not proof of observation
Information heard repeatedly can begin to feel familiar.
The witness may mistake this familiarity for evidence that the detail was personally observed.
For example, repeated discussion of a “dark jacket” may make the image easy to imagine.
When later questioned, the witness may report seeing the dark jacket even though the image was created from another person’s description.
Source monitoring and reconstruction
Eyewitness memory may be reconstructive rather than reproductive.
A reproductive account would be an exact replay of the original event.
A reconstructive account is rebuilt using:
Original information.
Later information.
Expectations.
Other people’s accounts.
Inferences about what probably happened.
Post-event discussion can supply material that becomes part of this reconstruction.
Memory conformity and source monitoring compared
Memory conformity | Source-monitoring error |
The witness adopts another person’s account | The witness confuses where a detail came from |
May involve social approval | Involves mistaken attribution of the source |
The witness may knowingly agree publicly | The witness may genuinely believe they observed the detail |
Can occur because another person appears more accurate | Occurs because information from different sources becomes confused |
Focuses on social influence | Focuses on memory processing |
The two explanations may operate together.
A witness may initially repeat another account because of social pressure. After repeating it several times, they may later forget its source and believe it was personally observed.
Gabbert and colleagues’ research
The purpose of the study
Gabbert and colleagues investigated whether witnesses would incorporate details obtained during a co-witness discussion into their own accounts.
The research allowed participants to view different information about the same event.
This created an opportunity for one witness to mention something that the other witness had not seen.
The procedure
Participants viewed an event from different perspectives.
The different viewpoints meant that each participant could see details that were not available to the other participant.
Participants then discussed the event before completing an individual recall task.
This is important because the final account was given individually. Any inaccurate details could therefore have been acquired from the earlier discussion.
Findings
A substantial majority of participants reported information that they had not seen but had acquired during the discussion.
AQA mark schemes identify the finding that approximately 71%Â of participants mistakenly recalled aspects of the event picked up from a co-witness.
This supports the claim that:
Co-witness discussion can contaminate memory.
Witnesses may adopt details supplied by another person.
Individual accounts are not independent after witnesses have discussed an event.
Why the research supports post-event discussion
The participants had viewed different information.
When a participant later reported a detail available only in the other person’s version, the detail could not have come from their own original view.
This provides evidence that post-event information influenced their later account.
The research supports both:
Memory conformity, because participants adopted another person’s information.
Source-monitoring errors, because they may have mistaken discussed information for something they observed.
Post-event discussion and leading questions
The main distinction
Both leading questions and post-event discussion involve misleading information received after an event.
The main difference is the source.
Leading questions | Post-event discussion |
Suggestion is contained in a question | Suggestion comes from another person’s account |
Often introduced by an interviewer or researcher | Often introduced by a co-witness |
Wording directs the witness towards an answer | Conversation allows accounts to influence one another |
May involve verbs or presuppositions | May involve memory conformity and source confusion |
Example: “How fast was the car when it smashed into the van?” | Example: “I clearly saw the driver holding a phone.” |
You can review suggestive wording through response bias and memory substitution.
Similarities between the two
Both can:
Introduce inaccurate information.
Affect later recall.
Reduce eyewitness accuracy.
Produce details that were not present.
Make the witness uncertain about the original event.
Alter a report without deliberate deception.
Be investigated using controlled experiments.
Both are forms of misleading information.
Differences in social interaction
Post-event discussion directly involves social influence between witnesses.
One witness may be affected by:
The confidence of another person.
A desire to agree.
The perceived expertise of the co-witness.
The majority view of a group.
Repeated exposure to the same account.
A leading question can affect a witness without any conversation between witnesses.
The influence is contained within the interviewer’s wording.
Differences in source monitoring
Both forms of misleading information could produce source confusion.
However, in post-event discussion the witness may confuse:
“I heard another witness say this”
with:
“I personally saw this.”
With a leading question, the witness may confuse:
“The interviewer suggested this”
with:
“This detail was present in the event.”
One situation can contain both effects
A witness may first discuss the event with another person and later receive a leading question from an interviewer.
For example:
A co-witness says that the offender wore a red hat.
The interviewer later asks, “How clearly could you see the red hat?”
The witness reports seeing a red hat.
Both factors may contribute to the error.
In an examination, identify the source of each suggestion rather than labelling every example simply as “misleading information”.
Applying post-event discussion to scenarios
A simple application example
Priya and Joel witness a road accident from opposite sides of the street.
Priya cannot see the driver’s hands. Joel later says that the driver was holding a mobile phone.
During a police interview, Priya reports seeing the driver use a phone.
This may be explained through post-event discussion because:
Priya did not originally see the driver’s hands.
Joel introduced the phone detail during their conversation.
Priya later included the detail in her own account.
Her testimony may have been contaminated.
Applying memory conformity
Priya may conform because Joel speaks confidently and claims to have had a clear view.
She may assume that Joel’s account is more accurate than her own.
Alternatively, she may agree because she does not want to challenge him.
A developed answer should explain why the other witness’s statement influenced the account.
Applying source monitoring
Priya may remember the phone detail but forget that she heard it from Joel.
She may wrongly attribute the detail to her own observation.
This would be a source-monitoring error.
A four-stage application structure
Use the following structure:
Identify the post-event discussion.
State what information the other witness introduced.
Explain how the account changed.
Apply memory conformity or source monitoring.
Weak application
Priya discussed the accident and became confused.
This lacks detail.
Stronger application
Joel introduced the claim that the driver was using a phone, although Priya could not see the driver’s hands. Priya later reports this detail as part of her own account. She may have made a source-monitoring error by confusing information heard from Joel with information she personally observed.
Identifying scenario clues
Scenario clue | Relevant concept |
Witnesses talk before separate interviews | Post-event discussion |
Witness accounts become increasingly similar | Memory conformity |
One witness appears more confident | Informational influence may occur |
A witness agrees to avoid an argument | Social approval or public conformity |
A witness remembers a detail but not where it came from | Source-monitoring error |
Information appears in an account despite not being visible | Memory contamination |
Suggestion is contained in an interviewer’s question | Leading question |
Designing research into post-event discussion
A possible procedure
A researcher could show pairs of participants two different versions of the same event.
The versions could differ in one critical detail.
For example:
Version A shows a person carrying a black bag.
Version B shows the person with no bag visible.
Participants could then be placed into one of two conditions:
Discussion condition, in which pairs discuss the event.
Control condition, in which participants complete an unrelated task.
All participants would then complete an individual memory test.
Independent variable
The independent variable, or IV, could be:
Whether participants discuss the event with a co-witness or complete the control task.
Alternatively, the study could manipulate whether the co-witness introduces a misleading detail.
Dependent variable
The dependent variable, or DV, could be:
The number of inaccurate details recalled.
Whether the participant reports the black bag.
The number of details adopted from the co-witness.
The percentage of participants showing memory conformity.
The measure should be clearly operationalised.
Why individual testing is important
Participants should give their final accounts separately.
If they complete the test together, one person could continue influencing the other person’s answers.
Individual testing allows researchers to examine whether the earlier discussion has affected each participant’s memory.
Control variables
The researcher should keep relevant factors constant, including:
The event shown.
The duration of the event.
The time allowed for discussion.
The delay before recall.
The questions used.
The testing room.
The instructions.
The length of the recall task.
Only the intended difference between conditions should change.
Standardisation
A standardised procedure could include:
The same video length.
The same instructions.
The same discussion time.
The same recall questions.
The same delay before testing.
The same method of recording answers.
This improves reliability and allows the research to be replicated.
Controlling the discussion
Natural conversations are difficult to standardise.
Different pairs may discuss:
Different details.
Different amounts of information.
The event for different lengths of time.
The information with different levels of confidence.
A researcher could use a confederate or structured discussion prompts to control which misleading detail is introduced.
However, making the discussion highly controlled may reduce its realism.
Demand characteristics
Participants may guess that the researcher is investigating whether witnesses influence one another.
They may then:
Deliberately agree.
Deliberately resist the other account.
Pay unusual attention to disagreements.
Avoid mentioning uncertain details.
This could reduce internal validity because the behaviour may be caused by awareness of the investigation rather than ordinary memory processes.
Ethical issues
Participants may need to be deceived about:
The true aim of the study.
The fact that different videos are being shown.
Whether the co-witness is a genuine participant.
The accuracy of information introduced during discussion.
Researchers should provide a full debrief and explain:
Why deception was necessary.
Which information was misleading.
That inaccurate recall is a normal memory effect.
How participants can withdraw their data.
Evaluating research into post-event discussion
Research support
Gabbert and colleagues found that participants frequently reported details acquired through discussion rather than their own observation.
The finding that approximately 71% mistakenly recalled discussed information provides strong support for post-event discussion as a factor affecting eyewitness accuracy.
The research demonstrates that:
Witnesses can contaminate one another’s accounts.
Discussion can influence later individual recall.
Agreement between witnesses does not guarantee accuracy.
Controlled procedures support causal conclusions
Researchers can control which version of an event each participant sees.
They can therefore identify details that:
Were present in one version.
Were absent from the other version.
Could only have reached a participant through discussion.
This allows a clearer causal conclusion:
Exposure to a co-witness’s account contributed to the inaccurate detail.
Individual recall strengthens the evidence
Testing participants individually after the discussion is important.
It shows that the participant continues to report the information after the co-witness is no longer present.
This makes the effect harder to explain as immediate conversational agreement alone.
However, it still does not prove that the underlying memory was permanently changed.
Research tasks may lack ecological validity
Participants often watch a film rather than witness a genuine crime.
A laboratory witness usually knows that:
The event is not real.
Nobody is in danger.
Their report has no legal consequences.
They are participating in research.
Real eyewitnesses may experience:
Shock.
Fear.
Personal involvement.
Genuine uncertainty.
Pressure to provide an accurate account.
Concern about the consequences of an error.
These differences limit the extent to which laboratory findings can be generalised to real eyewitness testimony.
Co-witness discussion has everyday realism
Although the original event may be artificial, discussing an experience with another person is realistic.
Real witnesses may talk:
Immediately after an incident.
While waiting for the police.
On social media.
With friends or relatives.
After hearing news coverage.
Before giving a formal statement.
The research therefore investigates a process that is likely to occur outside the laboratory.
Artificial discussions may be too controlled
In laboratory research, participants may be instructed to discuss an event for a fixed period.
Real conversations are less predictable.
Witnesses may:
Interrupt one another.
Express uncertainty.
Repeatedly discuss particular details.
Disagree strongly.
Receive feedback from several people.
Discuss the event over days or weeks.
A short structured conversation may not capture the full complexity of real co-witness influence.
Demand characteristics
Participants may notice that they saw different details.
They may infer that the study concerns memory conformity and alter their responses.
For example, they may assume that the other participant’s version is the correct one because the researcher has placed them together.
If this occurs, changed answers may reflect demand characteristics rather than ordinary eyewitness memory.
Memory change or social conformity?
A changed account does not automatically show that the underlying memory has been altered.
A participant may repeat another person’s detail because:
They want to agree.
The other person seems confident.
They believe cooperation is expected.
They are uncertain and choose the other response.
Their original memory may remain intact.
This makes it difficult to distinguish:
Genuine memory contamination.
Public memory conformity.
Informational influence.
Source-monitoring errors.
Source-monitoring errors provide a cognitive explanation
The fact that witnesses sometimes report discussed information as personally observed supports source monitoring.
The detail may be stored, but the witness misattributes its origin.
This explanation is valuable because it accounts for why a witness may sincerely report incorrect information.
However, source monitoring cannot be observed directly. Researchers infer the error from the participant’s report.
Warnings can reduce the effect
Research such as Bodner and colleagues suggests that warning participants about the possible influence of co-witnesses can reduce memory conformity.
A warning might remind witnesses that:
Other people may have seen different details.
Co-witness accounts may be inaccurate.
They should report only what they personally remember.
They should identify the source of each detail carefully.
This supports source monitoring because encouraging witnesses to consider the origin of information can improve accuracy.
Warnings do not necessarily remove the problem
Even after a warning, a witness may still struggle to separate:
Personally observed information.
Discussed information.
Suggested information.
Inferences about what probably happened.
Warnings may reduce contamination without eliminating it.
They may also make witnesses overly cautious and less willing to report accurate but uncertain information.
Practical applications
Research into post-event discussion has important applications.
Investigators should:
Separate witnesses as soon as possible.
Obtain individual statements before discussion occurs.
Ask witnesses not to compare accounts.
Record the timing of any co-witness conversation.
Ask witnesses where particular information came from.
Avoid confirming one witness’s account to another witness.
Warn witnesses to report only what they personally observed.
These procedures may help preserve the independence of each account.
Independent accounts are valuable
When witnesses give statements independently, similarities between their accounts provide stronger evidence.
Once witnesses have discussed the event, agreement becomes harder to interpret.
Their accounts may match because:
They observed the same event accurately.
One witness influenced the other.
Both received the same misleading information.
They agreed to avoid disagreement.
Investigators should therefore record statements before witnesses have an opportunity to contaminate one another’s memories.
Comparisons with leading questions
Leading questions and post-event discussion may both reduce eyewitness accuracy.
However, their mechanisms may differ.
A leading question introduces an assumption through wording.
Post-event discussion adds social processes, including:
Confidence.
Agreement.
Group pressure.
Perceived expertise.
Source confusion.
This means post-event discussion may require both cognitive and social explanations.
Anxiety may also affect eyewitness accounts
The accuracy of a witness may also depend on their level of anxiety during the event.
An anxious witness may:
Focus intensely on particular details.
Pay less attention to peripheral information.
Remember some aspects more clearly.
Remember other aspects less accurately.
This means that post-event discussion is only one influence on EWT.
The role of arousal is considered in the effects of anxiety on eyewitness accuracy.
Not all witnesses are equally influenced
Memory conformity may depend on:
Confidence in the original memory.
The confidence of the co-witness.
The witness’s viewing position.
The relationship between witnesses.
How long ago the event occurred.
How often the event is discussed.
Whether the witness has been warned.
The importance of the detail.
A person with a clear memory may resist misleading information more successfully than someone who is uncertain.
Real-world value
Even if laboratory studies simplify eyewitness experiences, the findings have significant practical value.
They demonstrate that police procedures can affect evidence quality.
Separating witnesses and obtaining early independent accounts are relatively simple actions that may reduce contamination.
Research with useful applications can be valuable even when the original task does not perfectly reproduce a genuine crime.
A balanced conclusion
Research supports the claim that post-event discussion can reduce eyewitness accuracy.
Co-witnesses may influence one another through:
Memory conformity.
Social approval.
Belief in another person’s accuracy.
Source-monitoring errors.
Incorporation of misleading details.
However, changed reports do not always prove that the original memory has been permanently altered.
The safest conclusion is:
Post-event discussion can contaminate eyewitness accounts, particularly when witnesses are uncertain, but its effects depend on social, cognitive and situational factors.
Comparing the two forms of misleading information
Feature | Leading questions | Post-event discussion |
Source | Interviewer or researcher | Co-witness or another person |
Method | Suggestive wording | Conversation or shared account |
Example | “Did you see the broken window?” | “I definitely saw a broken window.” |
Key processes | Response bias and substitution | Memory conformity and source monitoring |
Social pressure | May come from the interviewer’s authority | May come from agreement with co-witnesses |
Effect | Alters estimates or reported details | Makes witness accounts converge |
Practical response | Use neutral, open questions | Separate witnesses and obtain independent statements |
Both can be reduced through careful interviewing.
The cognitive interview aims to encourage extensive recall while reducing unnecessary suggestion from the interviewer.
Answering examination questions
Outline questions
For an outline question, include:
A definition of post-event discussion.
An explanation of memory contamination.
Memory conformity or source monitoring.
A relevant research finding.
Do not provide only a description of witnesses talking.
Application questions
Use details from the scenario.
Identify:
Who discussed the event.
Which detail was introduced.
Whether the witness originally saw it.
How it appeared in the later account.
Whether memory conformity or source confusion explains the effect.
Discussion questions
A strong discussion answer can include:
Research support from Gabbert and colleagues.
The effect of warnings.
Ecological validity.
Demand characteristics.
Difficulty distinguishing memory change from public conformity.
Practical applications.
Comparisons with leading questions or anxiety.
Effective paragraph structure
State the evaluative point.
Present relevant evidence.
Explain what the evidence shows.
Link directly to post-event discussion.
Reach a judgement.
Weak evaluation
Gabbert’s study supports post-event discussion.
Stronger evaluation
Gabbert and colleagues found that approximately 71% of participants reported details acquired during co-witness discussion. As participants had not seen these details in their own version of the event, the findings support the claim that discussion can contaminate later eyewitness accounts.
Hints from the Examiner Reports đź’ˇ
Examiner hint:Â Do more than state that witnesses discuss an event. Explain how the conversation can contaminate memory and reduce the accuracy of later recall.
Examiner hint: Use specialist concepts such as memory conformity and source monitoring. These terms help explain why another witness’s information appears in an individual account.
Examiner hint: Research evidence must be used, not merely named. Explain how Gabbert and colleagues’ findings support post-event discussion.
Examiner hint: Develop the psychological content. Answers that rely mainly on common-sense statements about witnesses “getting confused” are unlikely to reach the higher levels.
Examiner hint:Â Application should identify the specific detail acquired from another witness. Explain why the person may be unsure whether the detail was personally observed.
Examiner hint:Â Separate post-event discussion from leading questions. Post-event discussion involves information from a co-witness, while leading questions involve suggestive wording.
Examiner hint:Â Discussion can include difficulty distinguishing genuine memory change from public conformity, warnings about co-witness influence and comparisons with other factors affecting EWT.
Examiner hint:Â Keep evaluation relevant. A generic comment about an artificial study should be linked to whether the results apply to genuine co-witness discussions.
Common Mistakes ⚠️
Mistake: Defining post-event discussion as any conversation after an event
Why this is incomplete:
The discussion must be linked to its potential effect on the witness’s later account.
How to improve:
Explain that information from another person may contaminate memory and reduce accuracy.
Mistake: Saying that witnesses deliberately lie
Why this is incorrect:
A witness may sincerely believe that a discussed detail was personally observed.
How to improve:
Explain memory conformity or a source-monitoring error.
Mistake: Confusing post-event discussion with leading questions
Why this is incorrect:
The misleading information comes from different sources.
How to improve:
Identify whether the information was introduced by a co-witness or by the wording of a question.
Mistake: Using “memory conformity” as another name for ordinary conformity
Why this is incomplete:
Memory conformity specifically concerns one person’s account influencing another person’s reported memory.
How to improve:
Link the social influence to a detail from the witnessed event.
Mistake: Describing source monitoring as forgetting the whole event
Why this is incorrect:
The witness may remember a detail but misidentify where it came from.
How to improve:
State that the origin of the information is confused.
Mistake: Assuming matching eyewitness accounts must be accurate
Why this is incorrect:
The accounts may match because the witnesses discussed the event and adopted the same incorrect detail.
How to improve:
Consider whether the statements were obtained independently.
Mistake: Describing Gabbert’s research without a conclusion
Why this is incorrect:
Procedural detail alone does not show why the research matters.
How to improve:
Explain that reports of unseen details support co-witness contamination.
Mistake: Saying that a changed response proves permanent memory alteration
Why this is incorrect:
The participant may be conforming publicly without changing their private memory.
How to improve:
Discuss the difficulty of separating social conformity from genuine memory distortion.
Mistake: Giving a generic ecological-validity criticism
Why this is incorrect:
The criticism must explain how witnessing a film differs from witnessing a real incident.
How to improve:
Refer to personal involvement, genuine danger and legal consequences.
Mistake: Forgetting practical applications
Why this matters:
Research has clear implications for preserving eyewitness accuracy.
How to improve:
Explain why witnesses should be separated and interviewed independently.
Mistake: Copying the scenario without analysis
Why this is incorrect:
Application requires a psychological link.
How to improve:
Explain how the discussed detail entered the later account through memory conformity or source confusion.
Exam-Style Questions ✍️
Question 1
Which one of the following best describes a source-monitoring error?
A. A witness deliberately gives an incorrect account
B. A witness forgets every detail of an event
C. A witness confuses information heard from another person with information personally observed
D. An interviewer uses a forceful verb in a question
[1 mark]
reveal mark scheme and indicative content
Answer: C. A witness confuses information heard from another person with information personally observed
Question 2
Define post-event discussion in the context of eyewitness testimony.
[2 marks]
reveal mark scheme and indicative content
Mark scheme
AO1 = 2
2 marks:Â Clear definition referring to witnesses discussing an event after it has occurred, which may influence their subsequent memory or account.
1 mark:Â Limited or partial definition.
Example answer
Post-event discussion occurs when witnesses discuss an event with other people after witnessing it, which may introduce information that affects their later recall.
Question 3
Explain one difference between post-event discussion and leading questions.
[3 marks]
reveal mark scheme and indicative content
Mark scheme
AO1 = 3
1 mark:Â Post-event discussion involves information obtained from other witnesses or people after the event.
1 mark:Â Leading questions involve the wording of a question suggesting particular information or an answer.
1 mark:Â Clear comparison showing the different source of the misleading information.
Example answer
Post-event discussion involves a witness being influenced by information provided by another witness after the event. Leading questions involve misleading information being introduced through the wording of an interviewer's question.
Question 4
Two people witness a theft from different sides of a shop. Eliza cannot see what the offender is carrying. After the event, Noor says that the offender had a red bag. During a later interview, Eliza reports seeing a red bag.
Explain Eliza’s account using source monitoring.
[4 marks]
reveal mark scheme and indicative content
Mark scheme
AO2 = 4
Award 1 mark each for:
Noor provides Eliza with post-event information about a red bag.
Eliza did not originally see the bag herself.
Eliza later remembers the information but becomes confused about its source.
This source-monitoring error leads her to believe that she personally saw the red bag.
Example answer
Eliza hears from Noor that the offender had a red bag, even though she did not see this herself. Later she remembers the detail but confuses its source. Instead of remembering that Noor told her about the bag, she believes that she personally observed it. This source-monitoring error makes her eyewitness account inaccurate.
AQA describes source monitoring as distortion caused when alternative accounts are heard and the witness becomes confused about the origin of the information.
Question 5
Explain how memory conformity may reduce the accuracy of eyewitness testimony.
[4 marks]
reveal mark scheme and indicative content
Mark scheme
AO1 = 4
Award 1 mark for each relevant point, up to 4 marks.
Indicative content
Witnesses may discuss an event after it has occurred.
One witness may hear details reported by another witness.
The witness may conform to the other person's account, for example because they want social approval or believe the other person is more likely to be correct.
As a result, information that was not originally witnessed may appear in their later account, reducing accuracy.
Example answer
Memory conformity occurs when a witness changes their account so that it becomes more similar to another witness's account. They may do this because they believe the other witness is correct or because they do not want to disagree. As a result, misleading details from the other person's account may be reported as part of their own eyewitness testimony.
AQA specifically recognises the conformity effect as witnesses copying other people's accounts, including to gain social approval.
Question 6
Outline one study of post-event discussion and eyewitness testimony.
[4 marks]
reveal mark scheme and indicative content
Mark scheme
AO1 = 4
Award 1 mark for each relevant point, up to 4 marks.
Indicative content
For example, Gabbert et al. (2003):
Participants viewed an event from different perspectives.
Co-witnesses then discussed what they had seen.
Each participant had access to some information the other had not witnessed.
Participants later recalled details acquired from their co-witness.
71%Â mistakenly recalled aspects of the event they had obtained through discussion.
Example answer
Gabbert et al. showed participants different views of the same event and then allowed them to discuss what they had seen with a co-witness. The different versions contained details that were not visible to both participants. When later tested, 71% mistakenly recalled information that they had acquired during the discussion. This showed that post-event discussion can contaminate eyewitness memory.
AQA's 2024 mark scheme specifically credits Gabbert et al. and the finding that 71% of participants mistakenly recalled information picked up through discussion.
Question 7
A psychologist shows pairs of participants different versions of the same event. The pairs then discuss the event before completing individual recall tests.
Explain why showing different versions and testing participants individually are important features of this procedure.
[4 marks]
reveal mark scheme and indicative content
Mark scheme
AO2 = 4
Award up to 2 marks for each procedural feature.
Different versions
Each participant sees some information their partner has not seen.
Therefore, if a participant later reports a detail that appeared only in their partner's version, the researcher can identify that it was acquired through post-event discussion.
Individual testing
Prevents participants simply agreeing with one another while giving their answers.
Allows the researcher to measure whether information from the discussion has affected each participant's own subsequent account.
Example answer
Showing different versions means that each participant has access to information the other did not see. If someone later reports a detail that appeared only in their partner's version, it is evidence that the information came from the discussion. Testing them individually means their final answers cannot simply be copied from their partner at that moment, so the researcher can measure whether the discussion has influenced their own recall.
Question 8
A researcher investigated post-event discussion.
Condition | Percentage reporting a misleading detail |
No discussion | 8% |
Discussion with an uncertain co-witness | 31% |
Discussion with a confident co-witness | 67% |
Describe the pattern shown in the results. Use memory conformity to explain the difference between the conditions.
[6 marks]
reveal mark scheme and indicative content
Mark scheme
AO2 = 6
Award up to 3 marks for describing the pattern and 3 marks for explaining it.
Indicative content
Pattern
Misleading details are least likely with no discussion, 8%.
They increase to 31%Â after discussion with an uncertain co-witness.
They are highest after discussion with a confident co-witness, 67%.
Explanation
Post-event discussion provides an opportunity for memory conformity.
A witness may adopt information supplied by another person rather than maintain their own account.
A confident co-witness may be seen as more credible or certain, increasing pressure to accept their version and producing the highest level of conformity.
Example answer
Reporting of the misleading detail increases as the influence of the co-witness increases. Only 8% report it with no discussion, compared with 31% after discussion with an uncertain co-witness and 67% with a confident co-witness. Memory conformity can explain this because participants may adopt the co-witness's account. A confident co-witness may appear particularly reliable, so participants are more likely to accept their information and include it in their own testimony.
Question 9
A police officer says:
“There is no need to separate the witnesses. If their accounts agree after they talk, we can be more confident that they are accurate.”
Use your knowledge of post-event discussion to explain why this statement may be incorrect.
[6 marks]
reveal mark scheme and indicative content
Mark scheme
AO2 = 6
Award credit for clear application of post-event discussion to the officer's claim.
Indicative content
Allowing witnesses to discuss the event creates an opportunity for memory contamination.
Witnesses may conform to each other's accounts.
Agreement may therefore result from memory conformity, rather than independent memories of the same event.
Witnesses may also experience source-monitoring errors, believing information heard from another witness was personally observed.
Therefore, greater agreement after discussion does not necessarily mean greater accuracy.
Separating witnesses helps preserve independent accounts and makes genuine corroboration more meaningful.
Example answer
The officer's statement may be incorrect because discussion between witnesses can contaminate their memories. One witness may adopt details from another person's account through memory conformity, so their accounts become more similar even if the information is inaccurate. They may also make source-monitoring errors and believe that details heard during the discussion were personally witnessed. Therefore, agreement after discussion is not necessarily independent evidence that the accounts are accurate. Separating witnesses would help preserve independent testimony.
This concern is supported by Gabbert et al., where 71% of participants mistakenly recalled information acquired through discussion, showing that agreement between co-witnesses can reflect contamination rather than accurate independent recall. Â The 2024 examiner report also noted that the strongest responses on this topic used Gabbert's research, source monitoring and memory conformity.
Question 10
Discuss the effect of post-event discussion on the accuracy of eyewitness testimony.
[16 marks]
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