12.10.07 - Deception Detection

8/3/2019 12.10.07 - Deception Detection

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Centrality of deception

Interviews Importance of coming off as innocent

Miranda waivers Self-presentation of innocence, dont want to look

deceptive

Interrogation

Failure to convey innocence Presentation of false evidence

Maximization and minimization


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Deception Detection How doYOU stack up?


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Might professionals do better?

Kraut and Poe (1980) - customs officials no more accurate thancollege students in detecting deceit in mock customsexaminations.

Kohnken (1987) - police officers no better than chance whenjudging videotapes of college students who had lied or been

truthful

Underlying question: Were there really any information on thevideotapes to suggest differences? We presume there are actual differences between groups, but no

one has independently verified and quantified them.

If we KNEW there were differences, might professionalsoutperform students?


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Who can catch a liar?

Ekman & OSullivan (1991) Examine ability to detect deception in statements

about peoples feelings

part of talks Ekman gave to various groups Ps include:

Students and Extension Class (general public) Forensic Services unit of Secret Service Polygraph experts from FBI, CIA, NSA, Marines, Army,

Air Force, and other federal agencies Judges and Police Psychiatrists


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Ekman & OSullivan

Judge ten 1-minute videos Told that about half showed lies

Lie re: feelings about a movie subject was

watching Happy feelings during nature/horror film

Independently-verified differences between

liars and truth tellers! Facial muscle movements (fake/real smiles) Voice (pitch)

86% accuracy when using both


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Ekman and OSullivan Ps

Notice, were not talking about spring chickens,nor inexperienced lie detectors!


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Ekman & OSullivan

Questions How well do groups detect deception?

Do certain individuals stand out, obscured by mean?

How does confidence factor in?

What cues do people use? Related to accuracy?


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Ekman & OSullivan (1991)

Results Accuracy

Supports past work: people tend to perform poorly Only the Secret Service performed significantly above

chance!


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Ekman & OSullivan,breakdown Accuracy, continued

29% of Secret Service went at least 8/10! Psychiatrists next group of high scorers: 12% went at least

8/10


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Ekman and OSullivan

Results Demographic predictors?

Gender didnt matter

Younger were better in S.S. and polygraph pros

All who went 8/10 were under 40 years old

Were people appropriately confident? Asked how confident they were

in general (before task) About their performance (after task)

Neither correlated with performance (r = .03 and .02)


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Ekman & OSullivan (1991)

Results: Confidence Before and after the task

Secret Service, law enforcement personnel, and

polygraphers are significantly more confident than are

judges and psychiatrists. Why? Secret Service may have reason to be confident

Experience? Training?

Does police performance on task merit the

confidence? 55.79% accurate, on average!

Implications for interviews? Innocents in interrogation?


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Ekman & OSullivan

What tactics are associated with accuracy? Nonverbal behavior

People who were more successful listed behavioral cuesas basis of their decision (after the fact) But overall, people who said beforehandthat they were

going to use behavioral cues werent better than those whosaid they would use verbal cues

Microexpressions For extension class participants ONLY Tested for ability to recognize emotions conveyed through

microexpressions Weak correlation between accuracy and microexpression

r= .27; 7% of variance


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Ekman & OSullivan (1991) Issues

What constitutes good performance? Without trying, you can hit 50% by answering in one

direction for all items So is Secret Services 64% reallythat great?

Role of age/experience Age seems to be a hindrance. Why?

Ekman & OSullivan suggest less frequent interrogation

Slipping in old age? Havent learned newest techniques? Negative response bias tendency to see guilt

Remember Kassin & Fong, 1999, from last class


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Ekman & OSullivan (1991) Issues What are they even judging?

Positive feelings while watching nature film or gruesome

depiction

External validity? Do we want to make claims about how well lawenforcement performs based on tasks only marginally

related to their actual job?

Internal validity? Are the types of differences seen between liars and the

truthful in this experiment the same that show up in

criminal justice settings?


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A better deception detectionmousetrap

Mann, Vrij, & Bull (2004) 99 British police officers

Clips ofREAL interrogation footage Veracity of each statement was independently verified Watch a tape with several clips from different interviews

Experience operationalized as interrogation

experience, not age/years on force


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Mann et al. (2004) Questions

How accurate are police at detecting lies?

Does experience interviewing increase accuracy?

Do good and poor lie detectors rely differentially on speech-related cues?

Do Inbau-recommended behavioral cues limit accuracy?

Gaze aversion, unnatural posture changes, hand over mouthor eyes when speaking

Accuracy related to confidence?


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Mann et al. (2001) Results

Lie and Truth detection Lie accuracy: 66.16%

Truth accuracy: 63.61% Both significantly better than chance

Better than all but S.S. in Ekman & OSullivan (1991)

Interrogation experience and accuracy Lie accuracy r=.18, p


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Mann et al. (2001) Results

What do good v. poor judges rely on? Good

Illustrators (hand and arm gestures w/ story) Aspects of story

Poor Suspect gender (male seen as more guilty) More gaze aversion More head nods

Accuracy and confidence Not significantly related in truth or lie detection


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Ekman (1991) v. Mann (2004)

Why the differences in accuracy acrossstudies?

Different materials Higher stakes, more motivation

Maybe just easier to read these particular people No student comparison group in Mann, so we cant tell

British police officers cannot lie to suspects Need to be better at other abilities


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Why so poor? If chance is 50%, why do the most favorable

studies report only 60-65% accuracy amongpolice officers?

Reasons There is no ONE sign that someone is lying Differences result from withholding emotion, cognitive

load, and/or attempted control Can all work simultaneously

Can compete: eye blinking Nervousness increases blinking Cognitive load decreases blinking

Vrij (2004)


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Why so poor?

Reasons Heuristics Probing heuristic

If someone is questioned and isnt labeled as deceitful, they most

likely never will be thought of that way

Importance of the interview!!! Representativeness heuristic

Some behaviors are a stronger signal than others

Representative not necessarily accurate

Fidgeting erroneously believed to signal deception

FAE Over-reliance on dispositional attribution

Guilty before, guilty again bad apple theory

Come off as innocent, youre a good guy

Vrij (2004)


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Why so poor?

Reasons Failure to account for Individual Differences

Some peoples natural demeanor just makes them look

guilty/deceptive

Expressive people presumed innocent illustrators

Introverts

Lie less frequently, commit fewer crimes

More likely to look suspicious since they gesticulate less

Vrij (2004)


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Why so poor?

Individual differences and culture African-Americans display greater gaze aversion

than do those of European descent Same pattern among Turkish and Moroccan Dutch v.

White Dutch Power issues - SDO Eye contact polite in Western cultures, but extremely rude

in others, especially with someone of authority

Speech and behavior

South American immigrants to Netherlands make morespeech disturbances (ah speech) and self-manipulations (nonessential movement) Natural behavior is what White Dutch see as deceptive

Vrij (2004)


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Why so poor?

Feedback hypothesis (i.e. Training) Its not enough to simply make deception

judgments for a living

You need timely and accurate feedback about yourdecisions


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So who might do well?

How about criminals?


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Criminals and deceptiondetection

Environmental feedback Criminals may live in more deceptive environment

May need to be hyper-vigilant to keep from being

deceived Abused children living in institutional environment

significantly better at detecting lies (Bugental et al., 2001)

Recidivism

People tend to commit multiple crimes, get feedback onhow to be deceptive successfully Inmates can rapidly produce convincing false confessions

(Norwick, et al., 2002)


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Criminals and deceptiondetection Most lay people believe that deception is associated

with: Greater movement Less eye contact Less consistency in story, etc.

Criminals beliefs about the following were more inline with research than were students and prisonguards: Excessive consistency in story

Fishy if you make a lie and stick to it! Length of pauses in speech

Lying takes resources, need time to come up with something

Granhag, Andersson, Stromwall, & Hartwig, 2004


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Criminals and deceptiondetection

So do criminals actually make better liedetectors? (Hartwig et al., 2004) 52 Swedish prison inmates, 52 Swedish university

students

Evaluate video of eyewitness to a staged robbery Witness interviewed 3 hr, 4 d, and 11 d after attack

Told to tell what happened (or to lie and say the victim

initiated the knife attack and hurt himself in the process)

Decide whether witness was truthful and rateconfidence from 50% (guess) to 100% (certain) Provide cues used, if so inclined


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Hartwig et al (2004)

Types of cues provided Verbal

Witness confidence

Consistency across interviews

Degree of detail in account

Plausibility

Story sound rehearsed?

Nonverbal Body/trunk movements

Gaze Nervousness


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Hartwig et al (2004) Accuracy

Overall Criminals:65.4% - sig better than chance

Students: 57.7% - chance

If statement is Truth Criminals: 42.3%

Students: 50%

If statement is Lie

Criminals: 88.5% - sig better than chance Students: 65.4%


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Cues to Deception What cues did criminals and students say they

used? Criminals relied primarily on plausibility

34.6% of truth judgments, 28.8% of lie judgments Students use it 9.3% & 15.7%, respectively

34.9% of all correct judgments used plausibility Used significantly more often in correct judgment than in incorrect

judgment

Students rely primarily on consistency 24.1% of truth judgments, 30% of lie judgments

Criminals use it 0% and 5%, respectively

25.4% of all correct judgments used consistency Not used significantly more for correct judgments, always cited


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Criminal detection deception

Review Criminals may be environmentally-trained to detect

plausible stories to avoid neg. consequences of

being deceived Criminals beliefs about the role of consistency

more in line with research findings than are

students and guards

Criminals tend to be more accurate Greater reliance on plausibility, less reliance on

consistency in story across time


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12.10.07 - Deception Detection