accuracy of eye witness testimony: misleading information & anxiety

what is anxiety?

an unpleasant emotional state that is often accompanied by increased heart rate & rapid breathing

what does the yerkes-dodson effect show?

anxiety has a negative effect on performance when it is very low or very high, but moderate levels are actually beneficial

what was the aim of johnson & scott’s study?

to investigate if anxiety reduces the accuracy of eye witness testimony

what was johnson & scott’s procedure?

• pps asked to sit in a waiting room

• argument heard in next room

• a man runs through either holding a pen covered in grease or a bloody knife

• pps later asked to identify the man by photograph

what were the findings of johnson & scott’s study?

• 49% mean accuracy in pen condition

• 33% in knife condition

what did johnson & scott conclude?

anxiety focuses attention on central features of a crime but draws attention from other things - the weapon focus effect

what were ethical issues regarding johnson & scott’s study?

• informed consent not obtained

• distress - psychological harm

what was the aim of christianson & hubinette’s study?

to discover if anxiety can improve the accuracy of eyewitness testimony

what was the procedure of christianson & hubinette’s study?

• questioned 58 real witnesses to bank robberies in sweden

• witnesses were either victims or bystanders

• 4-15 months post robbery

what were the findings of christianson & hubinette’s study?

• all witnesses had over 75% accuracy

• most anxious (victims) had best recall

what did christianson & hubinette conclude?

memory for negative emotional events is better than for neutral ones

what was loftus & palmer’s aim?

to investigate how information provided to a witness after an event will influence their memory on that event

what was the procedure of loftus & palmer’s study?

• 45 pps shown short videos

• split into 5 groups

• asked ‘how fast were the cars going when they {} into each other

• smashed, collided, bumped, hit, contacted

what were the findings of loftus & palmer’s study?

• smashed had the highest mean speed estimate - 40.8mph

• contacted had lowest - 31.8

what was loftus’s procedure?

• 150 pps shown a short film of a car accident and questioned

• split into 3

• 1 - hit, 2 - smashed, 3 - no speed question

• asked if they saw any broken glass a week later

what did loftus find?

• the verb used in the original question influenced whether the pps thoguht they’d seen broken glass

• smashed - 32%

• hit - 14%

• control - 6%

what did loftus & palmer conclude?

eye witness testimony can be influenced by misleading questions

what is response bias?

the critical word influences or biases a person’s response

what are the explanations for loftus & palmer’s findings?

• response bias

• memory is altered

• post-event discussion

• conformity effect

what was gabbert et al’s aim?

to investigate if post-event discussion alters eye witness testimony

what was gabbert et al’s procedure?

• pps paired

• each watched different videos of the same robbery

• condition A were encouraged to discuss

• pps individually recalled

what did gabbert et al find?

• 71% of condition A pps mistakenly recalled items

what are the strengths of research into misleading information affecting eye witness testimony?

• supporting evidence - loftus headache study

• research used IRL in court

what are the limitations of research into misleading information affecting eye witness testimony?

• lab study - lacks ecological validity

• individual differences - age

• may be due to response bias

what are the strengths of research into anxiety affecting eye witness testimony?

• studied in a real-life context

• research support - violent crime has better eyewitness testimony accuracy

what are the limitations of research into anxiety affecting eye witness testimony?

• weapon focus effect may be due to surprise - pickel surprise study

• individual differences - neurotics have worse recall when anxious