Exam 2 Flashcards
Deception Detection (An Overview)
› Why do people lie?
o Be familiar with and able to provide an original example of each of the 4 different types of lies
-its an adaptive behavior; it is also a way to protect ourselves or others
-commission
-omission
-antisocial
-prosocial
Commission
saying things that are not true
Omission
leaving details out that are true/
important
Omission: leaving out details (denials, partial
admissions of guilt)
Antisocial
lie that protects or benefits oneself; increase or preserve reputation
Prosocial
lie to protect/ benefit others
What is the theory underlying this method of lie detection? That is, why do we think that humans should be able to detect lies by observing other people?
-deception detection
Are lay people good lie detectors? Why or why not?
No, lay people are better at detecting the truth; they rely on truth bias, however, they are only a little above chance at detecting deception.
Are police good lie detectors? Why or why not?
No, they are also only above chance at detecting deception, however they rely more on the lie bias, the idea that most people are lying.
More Confident
Compare the accuracy of lay people vs. police at detecting lies. Who do we think should be better? Why? Who is better?
o If police aren’t better than lay people, be sure that you are able to discuss why they aren’t better.
-Police because they are trained to detect deception
-Neither, both police and lay people are only above chance at detecting deception
Police not better than chance BUT more confident
• Why?
– Police are trained to detect deception using cues that
are not indicative of lying!
– Liar’s stereotype: avert gaze, squirm, stutter, touch
themselves
How well are CRIM 157 students able to detect deception (on the basis of the speed lying activity completed in class)? Compare your performance to the typical performance of police and lay people.
Prison inmates gave true and false
confessions on video
• Police detectives and college students
judged the truthfulness of the confessions
• Who does better?
– College student accuracy: 59%
– Police accuracy: 48%
• Police demonstrated a bias toward lies
– This biased increased with interrogation training
and job experience
Why are humans so bad at detecting deception? (Hint: We discussed 3 reasons)
Flawed interpretation of verbal and non-verbal
behavior
– Lack of feedback on accuracy of detection
techniques
– Confirmation bias
* Seeking & interpret confirming evidence of guilt while
ignoring plausible explanations (general nervousness)
What is the liar’s stereotype? Does this stereotype outline useful cues to use when trying to determine whether or not someone is lying? Why or why not? If the liar’s stereotype does not outline useful cues, what cues can/should we use (according to research), if any?
Behavioral indicators that
interrogators are told to focus on
are flawed indicators of deception
• Large international survey (n = 2500) found that 70%
of people believe liars avert their gaze, squirm, touch
their bodies more, and stutter when lying (Bond &
DePaulo, 2008)
• Confirmation bias
– When we form a strong opinion about someone, we seek
out information that confirms that belief and dismiss
information that contradicts that belief
What is confirmation bias? How is this related to deception detection?
– When we form a strong opinion about someone, we seek out information that confirms that belief and dismiss information that contradicts that belief
-we already have a set response towards someone else (lying or not lying) and that decision will weigh which type of evidence we will pay attention to and which evidence we will ignore, this can lead to false accusations
don’t consider all information/ evidence provided
What is the typical paradigm used in research to assess deception detection abilities?
The polygraph
What are limitations of lab research on detecting deception?
Lab Studies
• Know ground truth
• Low-stakes lies
• (i.e. write an essay
as punishment, or
more extra credit
as reward)
• Inexperienced liars
• (i.e. college
students)
Real World
• Don’t know truth
• Even if convicted
• High-stakes lies
• (i.e. prison time)
• Experienced liars
• (i.e. criminals)
One of the assumed reasons for the relatively poor unaided detection rate is that people have the tendency to believe— rather than disbelieve— information that is being presented (i.e., the “truth bias” or ‘truth-default,” McCornack and Parks, 1986; O’Sullivan, 2003; Levine, 2014). As a result, they often (mis)take a lie for truth. The Truth-Default Theory posits that as most communication is honest most of the time, the benefits of believing outweigh the costs of occasional deception (Levine, 2014; Clare and Levine, 2019). Consequently, people can detect truths with greater accuracy than lies (the veracity effect; e.g., Levine et al., 1999). If too much trust stands in the way of deception detection, wouldn’t being distrusted be the antidote for such gullibility?
Alternative deception detection approaches
Polygraph
Criterion based content analysis
fMRI
EEG
Infrared thermal imaging
Laser doppler vibrometry
Computer voice stress analysis test (CVSA)
What is the theory underlying this method of lie detection? That is, why do we think that the polygraph, a machine, should be able to detect lies? What does the polygraph measure in order to detect lies?
-Lying will cause physiological changes
- Measures: Heart beats faster, breath quicker, blood pressure increases, skin moisture
What are some of the weaknesses or limitations associated with using the polygraph to detect deception? (Hint: There are 6)
-emotionally non-reactive people
-no guarantee that innocent people won’t react strongly to questions about a crime
-convince suspect the polygraph is flawless
-lack of standardization
-use of countermeasures
-ethical grounds (personal questions)
o Research on the polygraph
* How accurate is the polygraph at detecting liars and truth tellers in the lab? In the field?
They claim high accuracy rates
– Test 100 people, 4 incorrectly classified but
96 correct = 96% accuracy rate
* Laboratory studies
– Mock crime, ½ commit crime, all deny
– Strength = ground truth known
* Field studies with actual suspects
– Strength = realism and high arousal
– Weakness = criterion of accuracy is subjective
– Criterion-Based Content Analysis
o What is the theory underlying this method of lie detection?
Analysis of written statements
o What is used/analyzed to determine whether someone is lying or telling the truth?
truthfulness assessment through systematic analysis of written statements
Assess truthfulness of a descriptive event
– Used to assess child truthfulness in CSA
o What results would indicate that someone is lying? What results would indicate that someone is telling the truth?
Rate strength of statements based on
criteria
– Logical structure
– Amount of detail
– Context (space and time)
– fMRI
o What is the theory underlying this method of lie detection?
Lies in the Brain:
fMRI
* Detects “where” lying occurs
o What is used/analyzed to determine whether someone is lying or telling the truth?
– Pre-frontal cortex and parietal
cortex = cognitive work
Detects differences between
rehearsed and spontaneous
lies
– Spontaneous – areas
associated with visual imagery
– Rehearsed – episodic memories
o What are the limitations of this approach to deception detection?
– Expensive, not portable, requires
cooperation
– Large individual brain differences
– No clear brain regions associated with truth
telling
– EEG
o What is the theory underlying this method of lie detection?
-detects “when” lying occurs