Factors effecting Eyewitness Testimony

Leading questions, post event discussion and anxiety

What are the two factors that affect eyewitness testimony

• Misleading information (Leading questions and post-event discussion)

• Anxiety

what are the three stages eyewitness memory goes through

• witness encodes info into LTM - partial as event can be quick, violent .etc.

• retains info for some time. memories can be lost, modified or other things may interfere with memory itself

• when needed retrieves memory from storage - absence of info can affect accuracy

Leading questions - Loftus and Palmer

Post event discussion - Gabbert

Anxiety - Loftus and Burns / Christianson and Hubinette

Weapons Effect - Johnson and Scott / Yule and Cutshall

___________ questions is one reason why accuracy of EWT is poor and usually done by police

leading - the incoming information can get confused with out previous known information

EXPERIMENT I INTO LEADING QUESTIONS (LOFTUS AND PALMER)

• AIM- investigate in general how accurate or inaccurate memory was - see the effect of leading questions

• PROCEDURE - 45 students, watched 7 films lasting 5-30 seconds of car accidents, given questionnaire after - first question was give an account of what they saw and the rest was questions about film. critical question How fast were the cars going when the (critical verb) each other. Wanted to see if they changed the critical verb would the speed estimate change.

• FINDINGS - smashed 40.5 and contacted 31.8

• CONCLUSION - response bias - the critical verb influences the different speed estimates - influences there memories

EXPERIMENT II INTO LEADING QUESTIONS (LOFTUS AND PALMER)

• AIM - investigate in general how accurate or inaccurate memory was - see the effect of leading questions

• PROCEDURE - 150 students, 1 min film scene showed of multiple car accident, measure whether they saw glass or not, 50 subjects - how fast car was when they smashed, 50 subjects - how fast car was when they collided, 50 not asked about the speed. Week later come back and complete questionnaire - critical question (did you see any broken glass)

• FINDINGS - more of those who asked if car smashed answered yes to seeing broken glass (16) compared to the ones who said hit (7)

• CONCLUSION - Substitution bias - memory is altered - critical word changes the memory and has been confabulated - actually believe that happened

Why do leading questions affect Eye Witness Testimony

1. Response bias explanation - wording of the questions influences how they decide to answer - encourages them to use that answer

2. substitution explanation - wording of leading question actually changes the participants memory

EXPERIMENT OF POST EVENT DISCUSSION (GABBERT 2003) - discuss the event with other and combine the misinformation from others with their own memories

• PROCEDURE - done in pairs, watch a video of same crime at different points of views - discussed after and completed a test of recall

• FINDINGS - 71% recalled aspects that were not in their video but picked up from discussion. control group 0%.

• CONCLUSION - memory conformity - could be to win social approval or actually believe they saw it wrong

A negative of the Loftus and palmer investigation into leading questions

• tasks is artificial - lacks the real emotions of a real accident

  • doesn’t explain the real life effect when actually seeing an accident

  • may tell us little how leading questions effect EWT in real life

  • cannot replicate an accident - unethical

• lacks population validity - only did university students and cannot compare to wider population

  • older people give less accurate EWT compared to younger people

  • some may be better at remembering than others

• Demand characteristics

  • want to appear helpful and attentive

  • not measuring what you are intending to - unreliable results

A positive into the studies of misleading information

• real-life application - important in practical uses in real world - teaches police officers to be careful how they phrase sentencing

  • can form a positive change - improves legal system

what is weapon focus

witness who observe an armed criminal to be more focused towards the weapon and don’t register criminals face

negative effect of anxiety research (Loftus and burns)

• shown violent version of crime of boy being shot in the face

• participants had impaired recall running up to the event

• anxiety - you try to repress the emotions

Positive effect of anxiety research (Christianson & hubinette)

• 58 real victims of a bank robbery - those who had been threatened had more accurate recall than onlookers

• memory recall had improved

STUDIES OF WEAPONDS EFFECT (JOHNSON AND SCOTT)

• PROCEDURE - believed taking part in lab study and assuming a casual conversation happening next door, 1) man walks out carrying a pen with grease on hands, 2) man walks out with knife covered in blood.

• FINDINGS - tried to pick out his face from photos - 49% identified man with pen with grease on hands and 33% identified man with knife

• NEGATIVE - some say study based on surprise rather than anxiety - as more surprised at what they’re holding rather than scared - can use pickle study here

  • due to unusualness rather than anxiety. Threat

  • has no specific effect of anxiety on EWT

• Ethical issues - fear that is created can cause psychological harm and deception was involved

• Lab study - can be replicated so high internal validity as done in a lab

STUDIES OF WEAPONS EFFECT (YULIE AND CUTSHALL)

• PROCEDURE - an actual event that occurred - shooting in a gun shop - owner shot the thief dead and 13 out of 21 took part in study. witnesses interview 4 to 5 months after event to recall what happened and explain emotions that time, compared to original police account given at the time

• FINDINGS -most accurate in their recall and accuracy - anxiety doesn’t have a detrimental effect on the accuracy on eye witness testimonies

• could not control the variables after the event - post discussion event could have occurred and other extraneous variables

  • difficult to assess by time participants are interviewed

• unethical to repeat the experiment

  • creates psychological harm

  • need real-life studies instead - interview people who already witness real life event so no need to recreate

Anxiety has both a positive and negative effect on memory - which law explains this

Yerkes - Dodson law - performance improves with increase of arousal until optimum point then declines with further increase

arousal levels improve memory to a certain point but too much anxiety and stress can cause memory to be difficult to recall

Pickel (evaluation point ONLY - NOT AO1)

• experiment conducted holding unusual items - scissors, handgun, wallet and raw chicken

• scissors (can still be a weapon) - but most unusual compared to the chicken

• not anxiety but rather unusualness