WEEK 5 Flashcards
what is the polygraph?
Sometimes called a “lie detector”.
It was assumed that lying is accompanied by physiological activity within liar’s body.
Polygraph tries to detect these signs by Displaying a direct representation of various types of bodily activity e.g. Sweating of fingers (GSR), blood pressure, respiration
what types of questions are used in questioning with polygraphs?
Comparison Question Test (CQT) and Guilty Knowledge Test (GKT) (aka Concealed Information Test).
what is comparison question test (aka control question test)?
The most commonly used and most disputed type of test
Compares responses to relevant questions with responses to control questions (about 10 in all)
what are the irrelevant or neural questions in the Comparison question test?
date of birth, name, address
what are the relevant questions in the comparison quesion test?
are specific questions about a crime
“On March 12, did you see Scott Fisbee?”
what are comparison questions in the comparison question test?
questions deal with acts that are related to the crime but do not refer to the crime in question
what are the characteristics of comparison questions?
General, vague, and cover long periods of time
Attempt to embarrass suspect to evoke arousal as they are given no choice but to lie
“Have you ever tried to hurt someone to get revenge?”,
”Have you ever taken anything from a workplace without permission?”
what are the assumptions of comparison question test for an innocent suspect?
Control questions generate more arousal than relevant questions because they respond deceptively to the control questions and truthfully to the relevant questions
what are the assumptions of comparison question test for a guilty suspect?
Relevant questions generate more arousal than control questions because they respond deceptively to both types of questions but the relevant questions present a more immediate threat to the suspect and so elicit a greater response
how are the differences in physiological reactions in the comparison question test rated?
subjectively by the tester (from -3 t0 +3)
what happens if a suspect fails the comparison question test?
they are pressured into a confession in the post-test interview
what is the aim the concealed information test?
Aim is to determine whether suspect has knowledge which they do not want to reveal about a particular crime
what are examples of the concealed information test?
A suspect has killed a person with a knife
They deny this during an interview
CIT examiner shows suspect a series of knives (including the one used in the killing) and asks for each one whether the suspect recognises it
Both innocent and guilty suspects will deny recognising each knife
The guilty suspect is will show a heightened physiological response when shown the correct knife
The CIT can only be used when sufficient specific details about the crime exist that have not been released to the public and that the criminal is likely to know about the crime
what are the problems with polygraphs?
Potentially low base rates of deception
Some people are emotionally nonreactive and so produce no physiological response when lying
Innocent people may still react strongly to questions about whether they committed a crime
Polygraphers have to convince the suspect that the polygraph is a flawless detector of lies
May involve lying which is not allowed in many jurisdictions
Suspect in CIT may admit having guilty knowledge but deny guilt
Lack of standardisation
Countermeasures may be used by suspect
Difficult to test the accuracy of the polygraph
why do polygraphs lack standardisation?
Scoring is subjective
Questions differ from test to test
How do countermeasures reduce the reliability of polygraphs?
the reduce the detection of lies by 50%
What are physical countermeasures used by suspects?
tongue biting
Pressing toes to floor
What are mental countermeasures used by suspects?
Counting backwards from 100
Imaging either a calming scene or an arousing scene
why is it difficult to test the accuracy of the polygraph?
Laboratory studies don’t involve the same severity of consequences
In field studies, we never know for certain who is lying
what was the polygraph’s accuracy for correctly classifying guilty suspects as guilty?
84-92%
what was the polygraph’s accuracy for correctly classifying innocent suspects as innocent?
69.7%
what was the polygraph’s inaccuracy for incorrectly classifying guilty suspects as innocent?
9.7%
what was the polygraph’s inaccuracy for incorrectly classifying innocent suspects as guilty?
9-24%
what was the polygraph’s inaccuracy for not being able to classify guilty suspects?
11.8%
what was the polygraph’s inaccuracy for not being able to classify guilty suspects?
14.8%
Why is nonverbal communication so important?
When verbal and nonverbal messages do not match, nonverbal behaviour the ‘better’ indicator of the truth (harder to control)
Why is nonverbal information harder to control?
Automatic links between emotions and nonverbal behaviours
(E.g., fear and automatic facial expression and body movement).
People unaware of what normal nonverbal behaviour is.
People are not practiced in controlling nonverbal behaviour.
what does nonverbal communication depend on?
Depends on type of lie used: fabrication ‘harder’ than concealment which leads to more disturbances
what factors influence deceptive behaviour?
stakes, motivation, planning and differences between lab and real police interviews
How do stakes influence deceptive behaviour?
high stakes result in nervous behaviour
How do motivation influence deceptive behaviour?
Highly motivated liars behave differently
Fewer movements, slower speech, higher pitch voice, more disturbances
How does planning influence deceptive behaviour?
‘Planned’ liars behave differently from spontaneous liars
Zuckerman & Driver (1985) – planning associated with fewer arm/head movements, shorter response latencies and faster speech rate
how do experimental situations influence deceptive behaviours?
Experimental situations do not involve the incredibly high stakes and cognitive load of the police interview
Who developed the concept of micro expressions?
Paul Ekman
what was the show ‘Lie to Me’ based on?
Ekman’s work
what are micro expressions?
Revealing facial movements that last for 40 milliseconds
and differ Across cultures
what is involved in the METT - Micro Expression Training Tool?
Trained to identify micro expressions, feedback, photos of faces with emotions,
large increases in accuracy with one hour training
Training, practice and feedback in detecting NV indicators improve skill
how many people are charged in the US based solely on eyewitness evidence?
7700 people per year
What happened in the Loftus experiment?
Small grocery store robbed, owner murdered, police caught a suspect
Group 1: Circumstantial evidence
Group 2: Circumstantial evidence + eyewitness testimony
Group 3: Same as group 2, but eyewitness shown to have poor uncorrected eyesight
Results: 72% of people who saw eyewitness evidence would convict
How many UK cases where only evidence was eyewitness testimony resulted in a conviction?
74%
What suggested that eyewitnesses are inaccurate?
Crash of plane into apartment building
Dutch media showed aftermath of crash
66% of participants reported having seen coverage of actual crash but there was no coverage…
what was the texas tech experiment?
Only 8% of Texas Tech students could correctly identify the perpetrator from a photo array in a staged purse snatching:The students entered the lecture hall, unaware they were about to become eyewitnesses to a crime. The suspect walks into the classroom, steals the purse and flees the room. Students asked to write down everything they could remember.
what is the process of memory?
encoding -> storage -> retrival
what happens in encoding of memory?
put information into memory
What happens in retrieval?
Using stored information
where can memory go wrong in the acquisition or encoding stage?
not paying enough attention
Where can memory go wrong in the retention or storage stage?
decay, forgetting, post-event feedback
Where can memory go wrong in the retrieval or recall stage?
forgetting, failure to communicate important items
what is a major cause for wrongful convictions??
faulty eyewitness testimonies
What is used to confirm the guilt or innocence of people already convicted of a crime?
DNA analysis. these are called DNA exoneration cases
what happened in the Innocence Project: New York?
In 36 out of the first 40 cases examined, mistaken eyewitness identification was the primary evidence,
Currently over 351 exonerations, of those 150 true suspects have been identified
Innocent persons served an average of 13 years
17 were sentenced to death before innocence proven using DNA
Eyewitness mistaken identification: factor in 75% of postconviction DNA exoneration cases in US
Griffith University Innocence Project
Western Australia Innocence Project
How can psychology contribute to the legal system?
assess the validity of an individual eyewithness
Prevent errors in the first place
what are the two types of variables that influence eyewithness errors?
system variables
estimator variables
how are estimator variables controlled to influence eyewitness testimonies?
Beyond the control of the justice system
Can only estimate the influence of the effect on a witness, not control it
E.g., the weapon effect
how are system variables controlled to influence eyewitness testimonies?
The justice system has control of these
E.g., the influence of lineup structure
What are estimator variables?
Environmental Conditions
when is identification accuracy poorer in estimator variables?
Target less salient Short exposure duration Weapon present Crime ‘less’ serious Perpetrator opposite gender to witness Race Arousal
why is research on system variables important?
Research on these is important because it can inform the justice system of ways to increase the accuracy of eyewitness statements
what are the two main categories of research of system variables?
event memory - memory for a critical event
identification memory - ability to select perpetrator from a lineup
what was a study on event memory?
Misleading questions: The Misinformation Effect
Loftus & Palmer (1974)
what did the Misleading questions: The Misinformation Effect
Loftus & Palmer (1974) experiment discover?
Memory is malleable and shaped by events that occur after a person witnesses an event
Schemas can be triggered by questioning which influences the way in which information is recalled or reconstructed
Memory reconstruction (1 week later)
Twice as many in the “smashed” condition reported the presence of broken glass
what are some statistics on the training in interviewing witnesses?
Sanders, 98% of US officers not trained in witness interviewing
George, in UK, out of 16 forces, 6 had no training and 10 had one day training.
Even when trained, the officers don’t tend to use the recall strategies
-ie., Officers were trained and then commenced interview, asked for free recall and then interrupted after only 7.5 seconds.
Officers receive little or no training conducting interviews with cooperative witnesses
What is the problem in the training of interviewing witnesses?
Despite an extremely large expenditure of time and money on training in basic investigative interviewing, witness interviewing remains the Achilles’ heel of police investigations. (Ede & Shepherd)
what are error made in police interviews that lead to the development of Cognitive interviewing?
Asking too many closed-ended questions and too few open-ended questions
Frequently interrupting eyewitnesses in the middle of narrative responses
Asking questions in a predetermined and inflexible order
what does cognitive interviewing attempt to enhance?
Attempts to enhance recall by improving elements of the interview:
The social dynamics and communication between the interviewer and the eyewitness
The eyewitness’s memory and other cognitive processes
how much did cognitive interviews compare to police interivews?
Between 35% and 55% improvement in amount of information recalled vs police interview with no increase in incorrect information
What is the benefit of cognitive interviewing accordining to Boon and Noon?
“The likelihood of retrieving a given memory will be enhanced where the characteristics and features of the retrieval cue overlap with those of the encoded input trace” (Boon and Noon, 1994)
what does varied retrieval of memory suggest?
There are multiple pathways to a memory and what is not readily available with one pathway may be available with another.
Use a different cue
what are the cognitive interview methods?
context reinstatement
Report everything
change perspective
reverse order
what is context reinstatement?
what were the physical/personal contexts at time of crime?
what is report everything?
include (perceived to be) irrelevant detail
what is change perspective?
place yourself in shoes of someone else at the scene
what is reverse order?
recall from a variety of chronological orders
what could be wrong with change perspective?
Hearsay
Speculation
Gives permission for witness to speculate/assume/conjecture
Question is confusing for eyewitness
Question is often confusing for officers
Alternate viewpoint may disrupt/alter actual original memory
what method is included in identification memory?
Lineups/photospreads
what are statistics of lineups/photospeads?
In the USA about 200 people per day become defendants as a result of these
what are some poor statistics about US law enforcement agencies?
Of 619 US law enforcement agencies (2013):
64% have no written policy for construction and administration of photo line ups
84% have no written policy for construction and administration of live line ups
what should a lineup include?
A lineup should contain only one suspect and several other known-innocent people (typically 7 in UK and Australia)
how should fillers in lineups be selected?
Fillers must be carefully selected based on similarity
Fillers should fit the verbal description of the perpetrator (or resemble the suspect in significant features if description is inadequate)
Do not want to make them too similar
Or too different
what can happen if you use dissimilar fillers in lineups?
Using fillers dissimilar to the suspect increases chances of false positive identification if suspect is innocent
what should eyewitnesses be told before the viewing in lineups?
Eyewitnesses need to be told that the perpetrator may or may not be in the lineup (Malpass & Devine, 1981)
Eyewitnesses might otherwise believe that the person who most closely resembles the perpetrator is the perpetrator
Surely the police would only go to the trouble of holding a lineup if they had apprehended the perpetrator?
what is the standard practice of lineups?
simultaneous not sequential
what does it mean by a simultaneous standard practice of lineups?
Fillers and suspect presented at the same time
Eyewitness tend to compare each person to determine which most closely resembles the perpetrator (Wells, 1984; 2013)
Unbiased instructions eliminate to some degree tendency to pick the person who most closely resembles the perpetrator
what does it mean by a sequential process of lineups?
Eyewitness is presented with one person at a time
Must decide for each if they are the perpetrator prior to being allowed to view the next person – a more absolute criteria
Results in an improvement in perpetrator absent lineups (Steblay, Dysart & Wells, 2011)
Mistaken identification: 43% with simultaneous presentation, 17% with sequential presentation
why is the relationship between eyewitness identification accuracy and confidence important?
People assume that a confident witness is an accurate witness (Wells, Lindsay, & Ferguson)
The judicial system endorses the view that an eyewitness’ certainty is an indication of their accuracy
What did Leippe find about confidence malleability?
Accuracy is a function of memory variables
Confidence is a function of social variables
how can eyewitness’ confidence me altered?
Mistaken eyewitnesses who are told that another agrees with their identification become more confident (Luus & Wells, 1994)
Repeated questioning also leads to greater confidence
Directing attention to decision process may reduce confidence
Generally the correlation is a poor .29
