1. Source Monitoring & Eyewitness Memory
Psychology 355: Cognitive Psychology Instructor: John Miyamoto 5/13/2015: Lecture 07-3
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2. Outline Memory is constructive Eyewitness memory
Source monitoring and source monitoring errors
Errors in eyewitness memory
Advantages & Disadvantages of Constructive Memory
Psych 355, Miyamoto, Spr '15

3. Advantages & Disadvantages of Constructive Memory
Constructive memory: Memories are constructed from: Original Experience + Other Associated Knowledge & Beliefs
Constructive aspect of memory is generally a good thing.
Advantages
Allows us to fill in the gaps in our knowledge.
Speeds up how quickly we can interpret or respond to a situation.
Helps create a meaningful narrative about our life experiences.
In general, cognition is inferential.
The schematic nature of memory – similar to Helmholtz’s “unconscious inference”.
Schemas help organize experiences into "chunks."
Disadvantages
Sometimes we make errors without realizing it.
Sometimes our memories are based on expectations and not on the actual experience.
Intro to Eyewitness Testimony
Psych 355, Miyamoto, Spr '15

4. Eyewitness Testimony
Basic source of evidence in the Anglo-American legal system.
Historically more trusted than circumstantial evidence.
Of 341 people who were exonerated by DNA evidence as of 2012, eyewitness testimony played a role in 75% of the original convictions. (Quinlivan et al., 2009; Scheck et al., 2000).
Sources of Error in Eyewitness Testimony
Psych 355, Miyamoto, Spr '15

5. Sources of Error in Eyewitness Memory
Intrinsic fallability of memory
Post-event suggestions by interested parties, esp. police.
Misleading post-event information (MPI) can bias memory
Misinformation effect
Misleading familiarity
Cross-racial identification
Feedback can reinforce memory errors
Line ups versus show ups.
Line up: Did one of these men do it? (People tend to respond as if the question is, who in this group looks the most like the person you saw?)
Sequential show up: Did Man A do it? Did Man B do it? etc. (Surprisingly less biased)
Source Monitoring & Source Misattribution
Psych 355, Miyamoto, Spr '15

6. Source Monitoring & Source Misattribution
Source monitoring - retaining a memory for the source of information in memory.
Source misattribution - attributing a memory to one source when the actual source was something else.
Example: My friends tell me about a large building fire that they witnessed. Years later I believe that I witnessed this fire along with my friends.
Source Misattribution & Errors in Eyewitness Memory
Psych 355, Miyamoto, Spr '15

7. Source Misattribution is One Cause of Erroneous Eyewitness Memory
Source misattribution can cause errors in eyewitness testimony.
A familiar face is more likely to be falsely identified as a perpetrator of a crime (witness thinks the familiarity is due to seeing this person commit the crime).
Example: A woman was attacked in her home shortly after watching a TV show in which a psychologist, David Thompson, was interviewed. Later she identified David Thompson as the attacker. (He had an alibi, the interview on the TV show.)
Remember/Know Distinction:
Feeling of familiarity ≠ Recollection but people may say that they "remember" Mr. X when Mr. X is familiar.
* Ironically, David Thompson studies memory distortion.
Ross et al. Experimental Study of Source Misattribution
Psych 355, Miyamoto, Spr '15

8. Source Misattribution & Eyewitness Identification
See Figure 8.17 in Goldstein
Robber Not Present
Try to pick robber from photospread; male teacher present
Experimental
View male teacher reading to students
Both Conditions
View female teacher getting robbed by a man.
Robber Present
Try to pick robber from photospread; male teacher present
Control
View female teacher reading to students
Ross, D. F., Ceci, S. J., Dunning, D., & Toglia, M. P. (1994). Unconscious transference and mistaken identity: When a witness misidenti­fies a familiar but innocent person. Journal of Applied Psychology, 79,
Same Slide with Emphasis Rectangles
Psych 355, Miyamoto, Spr '15

9. Source Misattribution & Eyewitness Identification
See Figure 8.17 in Goldstein
Robber Not Present
Try to pick robber from photospread; male teacher present
Experimental
View male teacher reading to students
Both Conditions
View female teacher getting robbed by a man.
Robber Present
Try to pick robber from photospread; male teacher present
Control
View female teacher reading to students
Ross, D. F., Ceci, S. J., Dunning, D., & Toglia, M. P. (1994). Unconscious transference and mistaken identity: When a witness misidenti­fies a familiar but innocent person. Journal of Applied Psychology, 79,
Results of This Study
Psych 355, Miyamoto, Spr '15

10. Robber not in photospread % Identification of Male Teacher
Results of Ross et al. (1994)
Figure 8.20: Ross et. al. (1994)
60% id male teacher when robber not in photospread.
20% id teacher in control group.
18% id male teacher when robber in photospread.
10% id teacher in control group.
Source misattributions can cause mistaken identifications.
Robber not in photospread
Robber in photospread
E C
% Identification of Male Teacher
E = Experimental Condition = View male teacher at stage 1
C = Control Condition = View female teacher at stage 1
Misinformation Effect
Psych 355, Miyamoto, Spr '15

11. Misinformation Effect
MPI = Misleading Postevent Information
Overview of the Misinformation Effect
Subject sees a video, or a slide sequence, or reads a story. I'll call this "the video." The video usually depicts a crime.
After seeing the video, the subject is asked questions about it. For some subjects, the questions contain misinformation (MPI or false assumptions).
Subjects receive a memory test. A misinformation effect is found if subjects who heard the misleading questions remember the video in a way that is consistent with the question and not the video.
Introduce Loftus & Palmer - Car Crash
Psych 355, Miyamoto, Spr '15

12. MPI: Leading Questions Can Produce Memory Biases
Loftus & Palmer (1974)
Subjects see film of an auto accident.
Questions contained alternative descriptions of the accident.
Results: Effect of the Biased Questions
Psych 355, Miyamoto, Spr '15

13. Leading Question Can Produce Memory Biases
Verb
Estimated Speed
smashed
40.8
collided
39.3
bumped
38.1
hit
34.0
contacted
31.8
Loftus & Palmer Result for Broken Glass
Psych 355, Miyamoto, Spr '15

14. Leading Questions Can Produce False Inferences
One week later, subjects were asked: Did you see any broken glass? Actually, there was no broken glass in the film.
Yes No
"smashed" 32 68
"hit" 14 86
control* 12 88
* The control group were not asked about the speed of the car (no misinformation; no correct information).
Misinformation Effect - Loftus, Miller & Burns
UW: Psych 355, Miyamoto, Win '12

15. Misinformation Effect: Loftus, Miller, & Burns (1978)
Subjects watch slides that show a traffic accident: Car A runs a stop sign and hits Car B.
Consistent Info Condition: How fast was Car A going when it went past the stop sign?
Inconsistent Info Condition: How fast was Car A going when it went past the yield sign?
Memory test: Did Car A go past a stop sign or a yield sign?
Results of Loftus, Miller & Burns Experiment
Psych 355, Miyamoto, Spr '15

16. Results of Loftus, Miller & Burns (1978)
% Correct Identification of the Stop Sign
#Section:
x <- c(0, 1/3, 1, 2, 7)
incon <- c(38, 42, 36, 30, 20)
neu <- c(85, 58, 61, 49, 50)
consis <- c(81, 70, 73, 67, 65)
plot.jm(x, incon, axes=F, xlim = c(0, 7), ylim=c(0, 100))
lines(x, incon, lwd=2)
lines(x, neu, lwd=2)
lines(x, consis, lwd=2)
points(x, incon, lwd=2, pch=15, cex=1.25)
points(x, neu, lwd=2, pch=16, cex=1.25)
points(x, consis, lwd=2, pch=17, cex=1.25)
axis(2, lwd=2)
abline(h=0, lwd=2)
lines(c(0,0), c(0, 2), lwd=2)
lines(c(1/3,1/3), c(0, 2), lwd=2)
lines(c(1,1), c(0, 2), lwd=2)
lines(c(2,2), c(0, 2), lwd=2)
lines(c(7,7), c(0, 2), lwd=2)
text(2, 73, "Consistent Info", cex=1.25, adj=0)
text(2, 55, "Neutral Info", cex=1.25, adj=0)
text(2, 34, "Inconsistent Info", cex=1.25, adj=0)
mtext("Retention Interval", 1, at=3.5, line = 2, cex=1.5)
mtext("Percent Correct", 2, at=50, line = 2.25, cex=1.5)
mtext(c("0", "20", "1", "2", "1"), 1, at = c(0, 1/3, 1, 2, 7),
line = -.75, cex=1.15)
mtext(c(" ", " min.", "day", "days", "week"), 1, at = c(0, 1/3, 1, 2, 7),
line = .1, cex=1.15)
#EndSection:
Misinformation Effect
A misinformation effect was found (it gets larger over time)
Chan: Recalling an Event Increases Susceptibility to Misinformation
Psych 355, Miyamoto, Spr '15

17. Recalling an Event Increases Susceptibility to Misinformation Effects
Chan, J. C. K., Thomas, A. K., & Bulevich, J. B. (2009). Recalling a witnessed event increases eyewitness suggestibility. Psychological Science, 20, 66–73.
Subjects view tape of "24" TV program.
Misinformation: A terrorist knocks out flight attendant with an injection of a drug, but the misinformation assumes that a chloroform pad was used.
Cued recall test increases tendency to recall misinformation.
Feedback Can Increase Confidence in Erroneous Memories
Psych 355, Miyamoto, Spr '15

18. Feedback Can Increase Confidence in Erroneous Memories
Subjects viewed video of crime.
Subjects shown a photo array that did not contain the perpetrator of the crime.
All subjects picked someone from the photo array. (!!!)
Confirming Feedback Condition: "Good, you identified the suspect."
No Feedback Condition
Disconfirming Feedback Condition: "Actually the suspect was number __."
Later when asked how confident they were in their identifications, subjects were most confident with confirming feedback.
Return to Slide Showing Sources of Error in Eyewitness Memory
Psych 355, Miyamoto, Spr '15

19. Sources of Error in Eyewitness Memory
Intrinsic fallability of memory
Post-event suggestions by interested parties, esp. police.
Misleading post-event information (MPI) can bias memory
Misinformation effect
Misleading familiarity
Cross-racial identification
Feedback can reinforce memory errors
Line ups versus show ups.
Line up: Did one of these men do it? (People tend to respond as if the question is, who in this group looks the most like the person you saw?)
Sequential show up: Did Man A do it? Did Man B do it? etc. (Surprisingly less biased) #
Psych 355, Miyamoto, Spr '15

20. Lineups versus Show-Ups – What Are They?
Classic showup: Police show only one person to a witness. Question: "Is he the man you saw?"
Classic lineup: Police show 7 people to the witness: Question: "Do you see the perpetrator in the line up?"
Improved showup = sequential showup: Police tell the witness, "We're going to show you a series of men (of unstated length). Stop me when you see the perpetrator."
Contrary to most people's expectations, show ups are more accurate than line ups. Why are showups more accurate than lineups?
Why Lineups & Showups Differ as Cognitive Tasks
Psych 355, Miyamoto, Spr '15

21. Cognitive Differences Between Lineups and Showups
Classic showup:
Witness asks himself/herself: "Did I see this person do the crime?"
Classic lineup:
Witness assumes that the perpetrator is in the lineup.
Witness asks himself/herself: "Which of these men looks the most like the person that I saw?"
Sequential presentation = sequential showup (Goldstein refers to this a sequential presentation)
With each person, the witness asks himself/herself: "Am I sure that this is the person who I saw do the crime?"
Lindsey & Wells (1985) found that the sequential showup greatly reduced false id when the perpetrator was not present (43% vs 17%)
Sequential showups slightly reduced the rate of true id when perpetrator is present.
Mistake!
Recommendations for Improving Eyewitness Memory
Psych 355, Miyamoto, Spr '15

22. Recommendations for Improving Eyewitness Memory
Use a sequential showup (Goldstein would call it a sequential presentation).
In a showup, use non-suspects who are similar to a suspect.
Inform witness that the perpetrator may not be in a showup.
Administrator of showup should not know who is the suspect.
Get confidence rating immediately after the initial identification. Avoid giving feedback to the witness after the lineup
Use cognitive interview techniques; do not prompt the witness with leading questions.
See Wikipedia article on cognitive interview techniques:
Cognitive interview technique includes:
Have witness mentally reinstate the environment and personal context of the event.
Have witness report in depth the details of the event, including details that may not seem important or relevant.
Describe the event in several different temporal orders.
Report the event from various perspectives, e.g., what could another witness see or hear?
Memory Accuracy & Memory Errors
Psych 355, Miyamoto, Spr '15

23. Memory Accuracy & Memory Errors
Psychologists are not claiming that memories are mostly errors.
We need to be aware that errors do occur, especially in situations where beliefs about memory accuracy have great practical importance.
In general, people are overconfident in the accuracy of their memories.
END
Psych 355, Miyamoto, Spr '15