PSYCH 3CC3 Lecture Notes - Lecture 4: Eyewitness Identification, Inattentional Blindness, Change Blindness
23 May 2018
School
Department
Course
Professor
Eyewitness Testimony
Lecture 4
Eyewitness Errors
• Dr. Donald M. Thompson
o He was on television talking about how one could improve their memory of faces and was
detained in 1975 for rape of a women
o The woman getting raped happened to look to the TV and saw Dr. Thompson on TV.
Remembered him from the time of the crime but couldn’t remember from where
• 73% of false convictions are based on mistaken eyewitness identification
Memory as an Adaptation
• We don’t have to remember everything – our past is constructed from little pieces of memories rather
than a long recording of events in our head, no memory before ~2 years of age, no information about
repeated events (things experienced over & over again aren’t remembered)
• Memory doesn’t need to be 100% accurate – memory as an evolutionary adaptation is meant to help us
get along between w/ others in the present or future. Doesn’t have to be accurate
• Blake, Nezarian & Castel (2015)
o Asked university students to recall & recognize the Apple logo. Only 50% of Apple product
users got it right even though they see it every day
Memory Processes
• Memory is broken down into 3 processes: encoding, storage, and retrieval
• Encoding – putting information from our senses into a form that can be stored in memory. May be
visual images of something that was seen or words (e.g. “I saw a brown cow” but not the actual image).
Affected by:
o Exposure duration – the longer the exposure, the better the encoding. In lineup studies, the longer
is better
o Arousal level – moderate arousal is best for encoding. Being extremely aroused/not aroused at all
during event → memory of event will be bad
o Distraction
▪ Inattentional blindness – not noticing something b/c attention is focused on something
else (e.g. Simmons & Chabris, video w/ gorilla walking through people passing
basketball around)
▪ Change blindness – not noticing the person has changed b/c didn’t encode information
about a person’s appearance
▪ More perpetrators – the more people there are, the worse people are at identifying people
(robbing a bank in a team is better than 1-2 people)
▪ Weapon focus – a form of inattentional focus where focus is on a weapon (esp. when
dangerous/loud) rather than the person holding it
o Distinctiveness – some accurate memories are vivid b/c they are distinct. People remember
exactly where they were, what they were feeling etc.
▪ Flashbulb memories – every generation has 1-2 of these which they remember (e.g., 9/11,
assassination of a president/famous person, explosions). They can still be inaccurate, no
matter how vivid the memory
• Storage – putting that encoded information somewhere in memory. Somethings don’t get stored or get
stored in places that can’t be found
• Retrieval – getting these memories back
• Storage/Retrieval Factors:
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o Labeling – explicit/self-generated labels affect recall. When individuals were shown drawings,
they were given a label (e.g., either sun or wheel, curtain or diamond) and 2 weeks later they
were asked to re-draw the image. What they drew was highly influenced by the label
o Prejudices & Biases – we store & retrieve memories consistent w/ our biases
▪ Boon & Davies (1996) – video of football game between 2 universities was watched by
students. Asked to count the # of penalties/fouls seen. Students recalled the other school
team having more fouls even though the same video was watched
▪ Buckhout (1974) – told southern Americans to see an image (tall black male dressed in
suit + short white male in overalls holding a weapon), a week later they recalled seeing
he black male as the one in overalls, shorter, and holding the weapon. Caused by
individual racial biases
▪ Bahrick et al (1996) – asked students to recall their high school grades. Individuals
recalled a higher percentage of high grades compared to low grades
• We tend to first forget things w/ no emotional context → then things w/ negative
connotations → positive memories (nostalgia)
o Inferences – remembering things b/c we expected them to happen, not b/c they occurred
▪ Bower & Treyens (1981) – participants asked to wait in a professor’s office for 10-15
mins while the experiment was being prepared. In the research room, they were asked
about contents in the room. Most people said there were books in there room but there
weren’t → people expected books to be in a professor’s office
o Interpolate retelling/testing – repeated retelling of events leads to reinforcing memories of things
that are mentioned and forgetting details that aren’t repeated often
o Leading questions – leading questions with even a difference in ONE WORD can make a
difference in memory recall
▪ Harris (1973) showed videos of basketball player. Asked leading questions like “how tall
was the basketball player” vs. “how short was the basketball player”. Leading q’s w/
how tall → taller average height reported compared to q’s asking how short
▪ Loftus (1975) – similarly asked leading q’s about headaches. “How many products tried,
1, 2, 3?” or “how many products tried, 1, 5, 10?” their answers were closer to the leading
numbers asked (higher when asked 1, 5, 10)
▪ Loftus & Palmer (1975) – individuals showed car accident video of 2 cars colliding,
asked to estimate speed of vehicles when they came together. Different words used in
asking question suggested different speeds
• Smashed > collided > hit > contacted > bump
• A week later, they were asked if any glass was present at the scene of the crime
(there wasn’t), and those who were asked “smashed” reported glass more than
“hit”
o Post-event information (PEI) – getting info after an event can be incorporated into your memory
of the event, even if it’s inconsistent w/ what you saw. Two theories:
▪ New info overwrites the old memory and access to the old memory is lost
▪ Original memory is still in there but the new info is stronger
Attorneys & Eyewitness Testimony
• Wise et al (2009) – surveyed 75 prosecutors and ~1200 defense attorneys on their knowledge of
eyewitness testimony
o Concluded that prosecutors don’t know a lot about the literature supporting r/t eyewitness
testimony; they rely on eyewitness testimonies too much even if it can be inaccurate
Offender Descriptions
• The type of information eyewitnesses provides
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Document Summary
Remembered him from the time of the crime but couldn"t remember from where: 73% of false convictions are based on mistaken eyewitness identification. Doesn"t have to be accurate: blake, nezarian & castel (2015, asked university students to recall & recognize the apple logo. Only 50% of apple product users got it right even though they see it every day. Memory processes: memory is broken down into 3 processes: encoding, storage, and retrieval, encoding putting information from our senses into a form that can be stored in memory. May be visual images of something that was seen or words (e. g. i saw a brown cow but not the actual image). Affected by: exposure duration the longer the exposure, the better the encoding. In lineup studies, the longer: arousal level moderate arousal is best for encoding. Being extremely aroused/not aroused at all during event memory of event will be bad is better: distraction.
