The Art & ScienceThe Art & Scienceof Lie Detectionof Lie Detection

Laura Freberg, Ph.D.Laura Freberg, Ph.D.Professor of PsychologyProfessor of Psychology

California Polytechnic State University, San Luis ObispoCalifornia Polytechnic State University, San Luis Obispo

laura@laurafreberg.comlaura@laurafreberg.com

Today’s AgendaToday’s Agenda

• What is a lie?What is a lie?

• Why do people lie?Why do people lie?

• When are they easy or hard to “catch?” When are they easy or hard to “catch?”

• How do people telegraph their truthfulness?How do people telegraph their truthfulness?

• What are the emerging technologies in lie detection?What are the emerging technologies in lie detection?

• A A quick video quick video of body language during a lieof body language during a lie

What Is a Lie?What Is a Lie?

According to the According to the American Heritage Dictionary, American Heritage Dictionary, a lie is:a lie is:

1. A false statement deliberately presented as being 1. A false statement deliberately presented as being

true; a falsehood. true; a falsehood.

2. Something meant to deceive or give a wrong 2. Something meant to deceive or give a wrong

impression.impression.

Note the emphasis on the person’s Note the emphasis on the person’s intent.intent.

Types of LiesTypes of Lies

• ““Protective” lies: Telling children that the stork Protective” lies: Telling children that the stork brought them because you don’t think they’re old brought them because you don’t think they’re old enough to talk about sex, or reassuring your relative enough to talk about sex, or reassuring your relative that he/she is not really terminally illthat he/she is not really terminally ill

• White lies: Lies that do no harm, and may do good, White lies: Lies that do no harm, and may do good, such as complimenting your hostess’ meal even if such as complimenting your hostess’ meal even if you didn’t enjoy it much (social tact)you didn’t enjoy it much (social tact)

• Lying by omission: Failing to reveal one’s belief in Lying by omission: Failing to reveal one’s belief in order to deceive.order to deceive.

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

More Types of Lies….More Types of Lies….

• Jest: When we use sarcasm or tell tall tales, we Jest: When we use sarcasm or tell tall tales, we assume others understand we are deliberately not assume others understand we are deliberately not telling the truth.telling the truth.

• Careful Speaking: Avoiding the telling of an outright Careful Speaking: Avoiding the telling of an outright lie with carefully chosen words; a half-answer that is lie with carefully chosen words; a half-answer that is accurate but does not fully answer a question.accurate but does not fully answer a question.

The Morality of LyingThe Morality of Lying

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

– Lying is a misuse of the human faculty of speech.

– Lying undermines trust, which is essential to the community.

– Lying undermines others; Lying makes a decision for the other person, rather than letting him/her decide based on facts.

• Others defend lying, such as telling a Nazi soldier Others defend lying, such as telling a Nazi soldier that one has no Jewish children in the house.that one has no Jewish children in the house.

Why Do We Lie?Why Do We Lie?

We are not alone. Deception is common in the animal We are not alone. Deception is common in the animal kingdom. All animals (including us) deceive others kingdom. All animals (including us) deceive others to obtain benefits or avoid costs.to obtain benefits or avoid costs.

Lying in AnimalsLying in Animals

• Koko, the female gorilla who uses American Sign Koko, the female gorilla who uses American Sign Language, signed “cat did it,” when confronted with Language, signed “cat did it,” when confronted with a sink she had damaged during a tantrum. It is not a sink she had damaged during a tantrum. It is not clear whether or not Koko was making a joke or clear whether or not Koko was making a joke or lying.lying.

• Wolves often “bluff” during ritual fighting that Wolves often “bluff” during ritual fighting that maintains the hierarchy within the pack. maintains the hierarchy within the pack.

The Development of LyingThe Development of Lying

• The ability is universal.The ability is universal.• Children demonstrate “Theory of Mind” at about the Children demonstrate “Theory of Mind” at about the

age of 4 years. Simultaneously, they are capable of age of 4 years. Simultaneously, they are capable of lying effectively.lying effectively.

• The ability to lie precedes a moral understanding The ability to lie precedes a moral understanding about the importance of honesty. Consequently, about the importance of honesty. Consequently, children lie frequently until they learn that this children lie frequently until they learn that this results in negative consequences.results in negative consequences.

• Adults probably lie as frequently as children, but Adults probably lie as frequently as children, but about different things.about different things.

Even Robots Will Even Robots Will Learn to DeceiveLearn to Deceive

• Laurent Keller’s robots react to theLaurent Keller’s robots react to theenvironment with a computerized “genome.”environment with a computerized “genome.”

• Bots that find food “mate” with other Bots that find food “mate” with other successful bots and send their “genome” successful bots and send their “genome” into the next generation. Bots can turn into the next generation. Bots can turn blue lights on and off.blue lights on and off.

• Bots “evolved” the ability to Bots “evolved” the ability to communicate with lights. Some flashed communicate with lights. Some flashed their lights near food, while others flashed their lights near food, while others flashed their lights near poison.their lights near poison.

• Bots gave correct information to “relatives,” but flashed their Bots gave correct information to “relatives,” but flashed their lights far away from food when surrounded by “strangers.” lights far away from food when surrounded by “strangers.”

““Catching” a LiarCatching” a Liar

Liars will look different ONLY when the following two Liars will look different ONLY when the following two conditions are fully met:conditions are fully met:

1.1. The person is deliberately and knowingly telling a The person is deliberately and knowingly telling a lie.lie.

2.2. The person thinks lying is wrong.The person thinks lying is wrong.

Reconstructive MemoryReconstructive Memory

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

• Elizabeth Loftus and Elizabeth Loftus and Eyewitness TestimonyEyewitness Testimony– Loftus (1975)– N=150– Video of an automobile accident– IV

“How fast was the white sports car going when it passed the barn while traveling along the country

road?”“How fast was the white sports car going while

traveling along the country road?”– DV – measured one week later

“Did you see a barn?”

Loftus’ ResultsLoftus’ Results

When People Don’t Care….When People Don’t Care….

• People who do not believe that lying is wrong will People who do not believe that lying is wrong will show few, if any, detectable signs of arousal.show few, if any, detectable signs of arousal.

• Psychopaths, criminal or not, are incapable of Psychopaths, criminal or not, are incapable of empathy or guilt. Therefore, they do not perceive empathy or guilt. Therefore, they do not perceive that harming others is a problem, and will be that harming others is a problem, and will be effective liars.effective liars.

Signs That a Person Is LyingSigns That a Person Is Lying

Detecting lies in people you know is FAR easier than Detecting lies in people you know is FAR easier than detecting lies in a stranger. When dealing with detecting lies in a stranger. When dealing with strangers, use baseline questions that nobody strangers, use baseline questions that nobody would lie about to establish “normal” behavior.would lie about to establish “normal” behavior.

Assuming a person is deliberately lying AND Assuming a person is deliberately lying AND recognizes lying as negative, you may observe recognizes lying as negative, you may observe some/all of the following:some/all of the following:

1.1. Reduced articulationReduced articulation

2.2. Facial and body responses that do not “match”Facial and body responses that do not “match”

3.3. Facial and body responses that pass quickly are are Facial and body responses that pass quickly are are replaced by more “conscious” responsesreplaced by more “conscious” responses

More Signs of LyingMore Signs of Lying

4.4. Reduced upper body movementReduced upper body movement

5.5. Increased lower body movementIncreased lower body movement

6.6. Nervous smiling or laughter that is inappropriate Nervous smiling or laughter that is inappropriate given the topic under discussion (smiling is a given the topic under discussion (smiling is a submissive signal—I’m okay, don’t hurt me)submissive signal—I’m okay, don’t hurt me)

7.7. Eye contact (works in the generic American culture, Eye contact (works in the generic American culture, but few others)but few others)

8.8. Timing: Emotions are spontaneous, instantaneous Timing: Emotions are spontaneous, instantaneous reactions to our environment. Any delay in reaction reactions to our environment. Any delay in reaction should be suspect.should be suspect.

Traditional Lie Detector TestsTraditional Lie Detector Tests

Polygraph tests are reliable about 65% of the time, Polygraph tests are reliable about 65% of the time, even when conducted by experts. Consequently, even when conducted by experts. Consequently, they are not admissible in court.they are not admissible in court.

Other Tech EffortsOther Tech Efforts

• ““Truth serum”Truth serum”• Brain fingerprintingBrain fingerprinting• fMRIfMRI

– 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

Other Challenges for fMRIOther Challenges for fMRI

• Small number of participantsSmall number of participants• Generally typical, law-abiding participants without Generally typical, law-abiding participants without

psychopathologypsychopathology• Can we generalize from the laboratory (no risk) to Can we generalize from the laboratory (no risk) to

the courtroom (huge risk)?the courtroom (huge risk)?

Lying Truth

Ethics of New TechnologiesEthics of New Technologies

• Technology generally moves much faster than Technology generally moves much faster than corresponding discussions of ethics.corresponding discussions of ethics.

• What if we can “read” the brain? How should that be What if we can “read” the brain? How should that be used? What protections should we have for used? What protections should we have for participants?participants?

Thank you! Any Questions?Thank you! Any Questions?

Feel free to email me Feel free to email me

laura@laurafreberg.comlaura@laurafreberg.com

OrOr

visit me on the web at:visit me on the web at:

http://www.laurafreberg.comhttp://www.laurafreberg.com