develop ability to spot a lie

7/29/2019 Develop ability to spot a Lie

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The Art & Science

of Lie Detection

Laura Freberg, Ph.D.Professor of Psychology

California Polytechnic State University, San Luis Obispo

[email protected]


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Todays Agenda

What is a lie?

Why do people lie?

When are they easy or hard to catch?

How do people telegraph their truthfulness?

What are the emerging technologies in lie detection?

A quick video of body language during a lie
http://www.videojug.com/film/how-can-i-tell-if-someone-is-lying-to-mehttp://www.videojug.com/film/how-can-i-tell-if-someone-is-lying-to-me


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What Is a Lie?

According to the American Heri tage Dict ionary, a lie is:

1. A false statement deliberately presented as being

true; a falsehood.

2. Something meant to deceive or give a wrong

impression.

Note the emphasis on the persons intent.


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Types of Lies

Protective lies: Telling children that the storkbrought them because you dont think theyre oldenough to talk about sex, or reassuring your relativethat he/she is not really terminally ill

White lies: Lies that do no harm, and may do good,such as complimenting your hostess meal even ifyou didnt enjoy it much (social tact)

Lying by omission: Failing to reveal ones belief inorder to deceive.

Bluffing: Usually considered more of a tactic than alie, as it occurs in the well-understood context of agame.


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More Types of Lies.

Jest: When we use sarcasm or tell tall tales, we

assume others understand we are deliberately not

telling the truth.

Careful Speaking: Avoiding the telling of an outright

lie with carefully chosen words; a half-answer that is

accurate but does not fully answer a question.


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The Morality of Lying

Many philosophers (e.g. Kant, Thomas Aquinas)prohibited ALL lying, even if it meant death.

Lying is a misuse of the human faculty ofspeech.

Lying undermines trust, which is essential tothe community.

Lying undermines others; Lying makes a

decision for the other person, rather thanletting him/her decide based on facts. Others defend lying, such as telling a Nazi soldier

that one has no Jewish children in the house.


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Why Do We Lie?

We are not alone. Deception is common in the animal

kingdom. All animals (including us) deceive others

to obtain benefits or avoid costs.
http://photos.mongabay.com/en/Monarch_Butterfly_Mimics.htm


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Lying in Animals

Koko, the female gorilla who uses American Sign

Language, signed cat did it, when confronted with

a sink she had damaged during a tantrum. It is not

clear whether or not Koko was making a joke or

lying.

Wolves often bluff during ritual fighting that

maintains the hierarchy within the pack.


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The Development of Lying

The ability is universal.

Children demonstrate Theory of Mind at about the

age of 4 years. Simultaneously, they are capable of

lying effectively.

The ability to lie precedes a moral understanding

about the importance of honesty. Consequently,

children lie frequently until they learn that this

results in negative consequences.

Adults probably lie as frequently as children, but

about different things.


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Even Robots Will

Learn to Deceive

Laurent Kellers robots react to the

environment with a computerized genome.

Bots that find food mate with other

successful bots and send their genome

into the next generation. Bots can turn

blue lights on and off.

Bots evolved the ability to

communicate with lights. Some flashed

their lights near food, while others flashed

their lights near poison.

Bots gave correct information to relatives, but flashed their

lights far away from food when surrounded by strangers.


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Catching a Liar

Liars will look different ONLY when the following two

conditions are fully met:

1. The person is deliberately and knowingly telling alie.

2. The person thinks lying is wrong.


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Reconstructive Memory

When we retrieve information from memory to use it, the data are atrisk for change. The person retrieving changed, inaccurate informationwill believe that he/she is telling the truth.

Elizabeth Loftus and Eyewitness Test imon y

Loftus (1975)

N=150

Video of an automobile accident

IV

How fast was the white sports car going when itpassed the barn while traveling along the countryroad?

How fast was the white sports car going whiletraveling along the country road?

DV measured one week later

Did you see a barn?


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Loftus Results


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When People Dont Care.

People who do not believe that lying is wrong will

show few, if any, detectable signs of arousal.

Psychopaths, criminal or not, are incapable of

empathy or guilt. Therefore, they do not perceive

that harming others is a problem, and will be

effective liars.


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Signs That a Person Is Lying

Detecting lies in people you know is FAR easier than

detecting lies in a stranger. When dealing with

strangers, use baseline questions that nobody

would lie about to establish normal behavior.

Assuming a person is deliberately lying AND

recognizes lying as negative, you may observe

some/all of the following:

1. Reduced articulation

2. Facial and body responses that do not match

3. Facial and body responses that pass quickly are are

replaced by more conscious responses


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More Signs of Lying

4. Reduced upper body movement

5. Increased lower body movement

6. Nervous smiling or laughter that is inappropriate

given the topic under discussion (smiling is asubmissive signalIm okay, dont hurt me)

7. Eye contact (works in the generic American culture,

but few others)

8. Timing: Emotions are spontaneous, instantaneousreactions to our environment. Any delay in reaction

should be suspect.


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Traditional Lie Detector Tests

Polygraph tests are reliable about 65% of the time,

even when conducted by experts. Consequently,

they are not admissible in court.


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Other Tech Efforts

Truth serum

Brain fingerprinting

fMRI

Brain activity during the processing of real memories

and imagined events is identical.

fMRI requires cooperation (no moving)

Cannot detect lies by omission

CAN detect if a person is thinking about a place

versus a face

CAN detect extra brain activity required by lying


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Other Challenges for fMRI

Small number of participants

Generally typical, law-abiding participants without

psychopathology

Can we generalize from the laboratory (no risk) tothe courtroom (huge risk)?

Lying Truth


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Ethics of New Technologies

Technology generally moves much faster than

corresponding discussions of ethics.

What if we can read the brain? How should that be

used? What protections should we have for

participants?


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Thank you! Any Questions?

Feel free to email me

[email protected]

Or

visit me on the web at:

http://www.laurafreberg.com
mailto:[email protected]://www.laurafreberg.com/http://www.laurafreberg.com/mailto:[email protected]

develop ability to spot a lie

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