BHS 499-07Memory and Amnesia

Memory and the Law

5 Ways Memory Affects the Law

Accuracy of eyewitness testimony Confidence of witnesses in their

memories Cognitive interviews that are most

effective at aiding memory Identification of perpetrators from lineups Effects of memory processes on juries

Wording Effects

During questioning of witnesses, wording affects the answers.• “How fast were cars going when they _____

each other?

• Choices were smashed, collided, bumped, hit, contacted

• Next, “did you see any broken glass?” – 7% Estimated speed – 40.8 with smashed &

16% saw glass, but 31.8 with contacted.

Misleading Postevent Info

When people are given misleading info after an event, it affects their memory for the event itself.• Consistent condition – yield sign was in video

• Misleading condition – stop sign not in video

• Control condition – no sign mentioned

Later given test -- 70% correct in consistent condition, 43% in misleading, 63% in neutral condition, with worse results after delay.

Theories

People who tell lies come to believe they are true later – a form of this effect.

Trace replacement theory – post info rewrites original info.

Coeexistence theory – both versions remain in memory but the misleading info is more recent so more accessible.• With warning, disregarded wrong info more.

More Theories

Response bias theory – guessing biases on the test account for the various %.• Tested using a new/old comparison without

the misleading info as a response choice.

Source monitoring theory – people forget the source of the misleading info, especially during reflective tasks.• Impact depends on the source of the info.

Arousal Influences

Emotion affects memory in complex ways.

Yerkes-Dodson Law – bystanders more likely to remember than victims.• U-shaped curve because optimum arousal

level.

Easterbrook Hypothesis – peripheral details weak, central details improved.

Arousal Influences (Cont.)

Weapon focus effect – increased memory for the weapon, decreased memory for everything else.• Occurs even when the weapon is not used.

John Dean’s Memory

John Dean’s memory of Watergate conversations was later compared to Nixon’s audio tapes for accuracy.• Dean was hardly ever right.

• Dean wasn’t deliberately lying.

• Important points were corroborated. Self-centered bias.

• Thoughts were incorporated into recalled conversations.

Eyewitness Confidence

Is a memory that a witness is unsure about less likely to be accurate?• Metamemory shows .41 correlation between

accuracy and confidence (excluding those who identified no one in the lineup).

Confidence increases with post-ID feedback on accuracy.

Telling a witness that others made the same choice increases confidence.

Confidence (Cont.)

The more times a person is asked the same questions, the greater the confidence in the answers.• Judges and juries are sway by confidence.

External motivation (reward) for remembering increases confidence.• When people try harder, difficulty of recall

cannot be used to assess accuracy.

Cognitive Interviews

Methods of gathering info have been developed to improve accuracy and prevent distortion.

First, attempt to reinstate the original context (internal and external) by having the person imagine or visit the scene.

Second, report partial info, whatever comes to mind, even if insignificant.

Interview (Cont.)

Third, report components of an event in a variety of orders, starting at different points.

Fourth, report the info from different perspectives.

Fifth, don’t interrupt. Technique takes time but boosts recall

up to 50% without increasing false info.

Eyewitness ID

Two kinds of errors:• Failing to ID a perpetrator

• Mistakenly identifying an innocent person

Mugshots – if people see a set of faces and the real perpetrator is not among them, they may ID someone else.• This commitment impairs the ability to later ID

the correct person, but just looking does not.

Lineups

Relative judgment principle – people not only compare the people to their memory but to others in lineup.• If others do not resemble the perp the one

who comes closest may be picked.

Lineup similarity – the physical resemblance of others in the lineup matters. Fillers must fit the description.

Lineups (Cont.)

Instructions should include a statement that the correct person might not be in the lineup.• Otherwise pressure to select someone,

anyone.

Errors more likely with a simultaneous lineup than a sequential one.• Forces a comparison with memory not others.

Lineups (Cont.)

Unconscious transference – an innocent bystander is identified as the perpetrator.

Memory bleeding explanation -- a person remembers seeing the person but becomes confused.

Source monitoring explanation – remembers the person but not the context.

Juries

Information order – juries try to construct info into a narrative.

To assess the impact of order two techniques are used:• Ask people to make decisions as they go

along – shows recency effect.

• Ask people to make decisions at the end, after all info has been given – primacy effect unless also given background info at start.

Inadmissible Evidence

Asking a jury to ignore inadmissible evidence is a directed forgetting request.• People are fairly efficient at doing this.

Juror’s memory for the inadmissible info is poorer than for the admissible info but it clearly has an impact on judgments.• Source info may be lost with forgetting.

Inadmissible Evidence

The more accurate jurors believe the inadmissible evidence to be, the more likely it will affect judgments.

Inadmissible evidence has a weaker impact during juror discussions because it can be identified and set aside.

Some inadmissible evidence comes from jurors themselves (their thoughts).

Children’s Testimony

It used to be thought that children did not or could not tell lies.• Now we know children can and do lie, even very

young children.

Effective prosecution of child abuse cases requires child testimony.

Special procedures used – shields, suspension of hearsay rules, mandated videotaping of interviews.

Children as Participants

Is memory different when children are participants in an event, not bystanders?• Pairs of 4 & 7 yo kids in a trailer playing games, one

playing and one observing

• Open-ended versus specific questions, some misleading

10 days later – older kids more accurate than younger, but no differences between observers & participants or suggestibility of abuse.

Pediatric Visit Study

5 & 7 yo girls on a pediatric visit• Half had a scoliosis exam, half a genital exam

• Tested at 1 & 4 weeks later Older children more accurate about all

questions, but no age differences for the misleading abuse questions.

More omission errors. While not easily misled there were a lot of

inaccurate answers to abuse-related questions.

Ornstein’s Studies

Significant age differences in children’s immediate and delayed recall.• 3 yo gave little open-ended info

As the delay increased considerable forgetting among the younger children.

Children laughed at the silly or strange questions asked.

Interviewing Techniques

Techniques that ask children to imagine things that may not have occurred or think about fictional events distort memory.

Use of peer pressure or authority affects memory.

Selectively reinforcing certain aspects of testimony introduces distortions.

Repeated interviews introduce distortions.

Repeated Questioning

Repeating misinformation across many questioning sessions results in impaired memory.

When misinformation is repeated eventually it is accepted by the child and becomes part of the child’s narrative.

Stereotype Induction

An attempt by the interviewer to transmit a negative characterization of a suspect.• Telling the child that the suspect “does bad

things” or “tries to scare children.”

Some children incorporate this info into their answers.

Emotional Tone of Interview

Setting a warm and supportive tone encourages children to resist intimidation and counter false suggestions.

Some “supportive” environments may include subtle bribes, threats or rewards.• “We know something bad happened”

• “You’ll feel better once you tell.”

• This kind of support makes children more likely to fabricate statements.

Confirmatory Bias

A neutral or unbiased interviewer who inadvertently uses a biased technique is less problematic than a biased one.

Confirmatory bias – seeking evidence in support of a single hypothesis instead of testing alternatives.• Results in use of suggestive techniques that

can distort memory.

Strength of Children’s Memories

While children’s memories can be changed by suggestive interviewing, children often show resistance to bias.

Children are not necessarily incorrect about everything – some facts will be correctly remembered.

Likelihood of disclosure is unrelated to threats made to children.