factors affecting the accuracy of eyewitness testimonies

what r the factors affecting the accuracy of eyewitness testimonies

• misleading information

• anxiety

what are leading questions

questions which suggest a certain answer because of the way it’s phrased.

who did research on leading questions

Loftus and Palmer

what was the research on leading questions

Loftus and Palmer

arranged 45 participants to watch film clips of car accidents then asked questions about accident

in critical questions (leading question/misleading information) participants asked to describe how fast the cars were travelling

5 groups and each group given different word in critical questions (either hit, contacted, bumped, collided, smashed)

verb ‘contacted’= mean estimated speed of 31.8mph

verb ‘smashed’ = mean estimated speed of 40.5mph

The leading question affected the eyewitness’ recall of the event

what is the response bias explanation

suggests wording of question doesnt affect participants memories, just how they decide to answer.

loftus and palmer 2nd experiment : participants who originally heard ‘smashed’ more likely to report seeing broken glass (there was none) than those who heard ‘hit’ → supported substitution explanation (wording of a leading question changes participants memory)

what is post event discussion

witnesses to an event discuss, with co- witnesses, what they have seen. This may influence the accuracy of each witnesses recall of the event.err

research on post-event discussion

Gabbert et al studied participants in pairs

each participant watched a video of the same crime but from different points of views

both participants discussed what they had seen individually before individually completing a task of recall

71% participants mistakenly recalled aspects they didn’t see in video but had picked up from discussion

in control group of no discussion, 0% participants mistakenly recalled aspects they didn’t see in video

→ evidence of memory conformity

what is memory contamination

when co-witnesses to a crime discuss it w eachother, their eyewitness testimonies may become altered or distorted. this is bc they combine misinformation from other witnesses w their own memories

what is memory conformity

witnesses go along w eachother either to win social approval or bc they believe other witnesses r right and they r wrong

unlike memory contamination, the actual memory is unchanged

strengths of research into misleading information

practical use in criminal justice system

leading qs can have such a distorting effect on memory that police officers need to be careful ab how they phrase their questions when interviewing eyewitnesses.

shows psychologists can help improve the way legal system and can [rptect innocent ppl from fault convictions based on unreliable eye witness testimonies

application

counterpoint

these practical applications may be affected by issues w research

Loftus and palmer’s particpants watched film clips in lab (laboratory experiment)

different experience from witnessing real event → less stressful

participants responses in research do not matter in same way as real eyewitnesses bc real eye witness testimonies has actual consequences

weaknesses Forfar substitution explanation

eye witness testimonies more accurate for some aspects of an event than for others

Sutherland and Hayne:

→participants shown video then asked misleading qs. their recall more accurate for central details of event than for peripheral ones

→participants attention was focused on central features so these memories relatively resistant to misleading info

substitution explanation incomplete explanation bc original memories for central details not distorted

weaknesses for memory conformity

what is anxiety

a state of emotional and physical arousal. emotions include having worried thoughts and feelings of tension. physical changes include increased heart rate and sweatiness. Can affect accuracy and detail of eyewitness testimony

wy would anxiety have a negative effect on recall

anxiety creates physiological arousal in body= prevents paying attention to important cues=recall is worse

who did research on anxiety having a negative effect on recall

Johnson + Scott

what was Johnson + Scott study

told participants they were taking part in lab study

low anxiety condition : heard casual convo in next room then saw man walk past carrying a pen w grease on his hands

high anxiety condition : heard argument + glass smashing then saw man walk out of room holding knife covered in blood

later participants picked out man from set of 50 photos.

49% who saw man carrying pen were able to identify him

33% who saw man carrying knife covered in blood were able to identify him

tunnel theory of memory suggests ppl have enhanced memory for central events → weapon focus as a result of anxiety

how does anxiety have a positive effect on recall

witnessing stressful event = creates anxiety through physiological arousal within the body = triggers flight or flight response = increases alertness = may improve memory for event as we become more aware of cues in situation

who did research on anxiety having a positive effect on recall

Yuille and Cutshall

what was Yuille and Cutshall study

actual shooting in a gun shop in Vancouver, Canada

shop owner shot theif dead

21 witnesses → 13 took part in study → interviews 4-5 months after incident. these interviews were compared w original police interviews at time of shooting

accuracy dtermined by number of details reported in each account

witnesses also asked to rate how stressed they felt at time of incident (on 7 point scale) + whether they had any emotional problems since event

witnesses vry accurate in accounts + there was little change in amount recalled or accuracy after 5 months

particpants who reported highest levels of stress = most accurate (ab 88% compared to 75% for less stressed group)

suggests anxiety does not have bad effect on accuracy of eye witness memory in real world context

Yerkes - Dodson law

relationship between anxiety + accuracy of eye witness testimonies → inverted ‘U’

too little/too much anxiety lowers levels of recall accuracy

optimum level of anxiety → maximum recall accuracy

strengths of anxiety affecting eyewitness testimonies

evidence supporting view anxiety has negative effect on accuracy of recall

Valentine and Meson : used an objective measure (heart rate) to divide particpants into high + low anxiety groups

in this study, anxiety disrupted partipcnats ability to recall details ab the actor in the London Dungeon’s Labyrinth

suggests high levels of anxiety does have negative effect on eyewitness recall of stressful event

strengths of anxiety affecting eyewitness testimonies

evidence showing anxiety can have positive effects on accuracy of recall

Christianson + Hubinett interviews 58 witnesses to bank robberies in sweden

researchers assumed witnesses directly involved (eg bank workers) would experience most anxiety than witnesses indirectly involved (eg bystanders)

recall more than 75% accurate across all witnesses

these findings for actual crimes confirm anxiety doest reduce accuracy of recall for eyewitnesses

counterpoint

Christianson + Hubinette interviewed their participants several moths after event → researcher had no control over what happened to particpants in between (eg post event discussions) → lack of control over confounding variables → weakens research as support so lowers validity

weaknesses of anxiety affecting eyewitness testimonies

Johnson and Scott study may not have tested anxiety

maybe participants focused on weapon bc they were surprised rather than scared

Pickel conducted experiment using scissors, a handgun, a wallet or raw chicken as hand-held items in hairdressing salon video

scissors=high anxiety, low unusualness

eyewitness accuracy significantly poorer in high unusualness conditions (chicken+handgun)

suggests weapon focus effect due to unusualness rather than anxiety → lack of internal validity of Johnson and Scott study