Lie Detection Final

7/30/2019 Lie Detection Final

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Lie Detection


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History of Lie Detection

Current Methods What is the validity of lie

detectors?

Legal Issues

Can you beat a lie detector?

How to tell when someone is lying How to lie


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History of Lie Detection Greeks would ask questions and feel the subjects pulse.

Torture as a means of interrogation: Romans used crucifixion.

Strappado was a means of medieval inquisition torture whichwould dislocate joints. The rack would stretch the victims jointsto breaking point. Red hot pinchers would be applied

Modern: Leave a victim with no visible damage.

In 1948, following the horrific abuses of World War II, the

General Assembly of the United Nations inserted theprohibition against torture in the landmark UniversalDeclaration of Human Rights. Article 5 states: "No one shallbe subjected to torture or to cruel, inhuman or degradingtreatment or punishment." The prohibition against torture iswell established under customary international law as

jus cogens .

The Supreme Court in 1963 ruled that a confessionextracted under truth serum drugs such as sodiumpentothal, sodium amytal, and scopolamine - violated adefendant's constitutional right against self-incrimination.

Should torture/ truth serum be permitted if its usewould save lives or benefit society?


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Current MethodsModern polygraphy: uses physiological changes in the peripheral nervous system

(PNS) measure deception1. Skin conductance changes (sweating)

2. Blood pressure

3. Respiration

4. Heart rate

Facial Micro-expressions(developed by Paul Ekman)

It would have the advantage of not requiring any obvious intervention with thesubject. Could be used secretively by videotaping.

Neurotechnological Lie Detection (NTLD):

Measurements of blood flow or electrical impulses in the brain to identify distinctindicators of deceptive communication.

Measure lying more directly by measuring brain activity rather than second-order

indicators like pulse or respiration.Advantages over polygraph testing:

Fear or other strong emotions may affect physiological responses and thus mayconfound the data in polygraphy.

Polygraphy requires trained experts to read the graphs, while NTLDs would onlyrequire computers.

Does this mean that NTLDs are reliable evidence in court?


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Two categories of NTLD1. Blood Flow Patterns

By studying blood flow patterns during deception andcomparing them to blood flow patterns during non-deception in similar situations, researchers can learnwhich regions of the brain are activated when peopleare lying.

Functioning Magnetic Resonance Imaging (fMRI) iscurrently the most commonly used method formeasuring blood flow in the brain. Images areconstructed based on blood-oxygenation-leveldependent (BOLD) contrast. When a brain region ismore metabolically active, there is a local increase in

MR signal or BOLD contrast. When people lie, theanterior cingulate cortex is activated. No Lie MRIstarted offering its fMRI-based lie detection services in2006.

Near-infrared spectroscopy (NIRS) focuses onactivity in the prefrontal cortex and provides a way tomeasure changes in blood flow without the complexapparatus of an MRI machine. The basis of thetechnology is the measurement of how near infraredlight is scattered or absorbed by various materials.Small devices are attached to the subjects skull, whichshine near-infrared light through the skull and into thebrain. This scattered laser light is picked up by sensorson the subjects skull. The pattern of scattering revealsthe pattern of blood flow through the outer regions ofthe brain.

Thermal imaging: When people lie their eyes give off

more heat.


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1. Patterns of Recognition

Use event related potentials (ERPs) through electroencephalogram(EEG) to identify patterns of recognition for the wave pattern of theP300 wave. With EEG, the researcher uses electrodes placed onthe subjects scalp to detect and measure patterns of electrical

activity emanating from the brain. Brain fingerprinting attempts to discern whether a person has

knowledge of a particular event or an image stored in his brain. TheP300 wave occurs when a subject recognizes information or afamiliar stimulus. It is the only technique considered for admissioninto evidence.


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Is this ethical?

Because these methods rely on correlations to determine lies, arethey reliable?

Should personal privacy be sacrificed for the better of societybecause NTLDs could serve forensic, security, and militarypurposes? Is personal pr ivacy even being invaded?

What about the self-incrimination clause of the Fifth Amendmentthat states that no person shall be compelled in any criminal case tobe a witness against himself?

Garnering the evidence vs. entering the suspects mind is violating

Brain imaging and brain fingerprinting require clear testimonialresponse from the suspect, such as pressing a button. Is this thesame as blood or hand writing samples used to solve a crime?

Previously, in order for the contents of a persons mind to beexposed, he had to communicate that content actively, whether byspeaking, writing, gesticulating, or some other deliberate means. Isthis still considered communicating?


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What is the validity of lie detectors?United States v. Scheffer (1998):

A host of studies show that polygraph testing shows 85% to 90% accuracy while critics state that itis 70%.

More likely to show innocent people guilty than vice versa.1. False positive

Leads to an incorrect accusation against the communicator. These may be more serious thanfalse negative.

2. False Negative

The "liar" gets away with the lie. This has been the traditional focus

for assessment of the accuracy of a communication.

Polygraph tests can discriminate lying from truth telling at rates well above chance but well below

perfection. Hence, for the control question theory to be valid, two assumptions must hold. The first requires

innocent individuals to be more responsive to control than relevant questions. The second requiresguilty persons to respond more intensely to relevant than control questions. The plausibility of bothof these assumptions can be easily challenged.

The notion that guilty suspects will necessarily respond more strongly to relevant than controlquestions is unlikely for several reasons.

The notion that a guilty suspects will necessarily respond more strongly to relevant than control

questions is unlikely for several reasons. If a guilty person passed the test, there would be no confession to guilt and that the test waswrong? So how accurate are the studies dont for lie detection?

How can lie detection be verified as accurately recording the truth or not?

Brain fingerprinting:Is this an accurate method when people have memory problems? What ifsomeone is telling the truth but is factually wrong?

There is not a 100% accurate way lie detection method


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Legal IssuesFrye vs . United States:The Frye standard is a legal precedent regarding

the admissibility of scientific examinations or experiments in legal

precedings. To meet the Frye standard, scientific evidence presented tothe court must be interpreted by the court as "generally accepted" by ameaningful segment of the associated scientific community.

Daubert v . Merrel l Dow Pharmaceuticals (1993):The Daubert standard isa legal precedent regarding the admissibility of expert witnessestestimony during legal proceedings.

United States v. Scheffer (1998): Military Rule of Evidence 707 (failure totake, or taking a polygraph examination shall not be admitted intoevidence) v. 6th Amendment (right to defend oneself)

AfterUnited States v. Scheffer, most jurisdictions exclude all polygraphicevidence. However, two federal circuits held that polygraphic tests couldbe admitted on a case-by-case basis and New Mexico admitted

polygraphic evidence.The Employee Polygraph Protection Act of 1988:

Established guidelines for polygraph testing and imposed restrictions onprivate employers such as companies and corporations

Does NOT affect public employers such as police agencies or othergovernmental institutions.

Should p ubl ic employ ers be trusted more than p r ivate employers?


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Legal Issues cont.Iow a v. Harr ington

a post-conviction relief action undertaken 26 years after amurder; EEG responses to probes such as acrossstreet, parked cars, and weeds and grass, all of whichrelated to the crime scene, showed that he had nomemory of the crime; the district judge ultimately did notfind the evidence persuasive

By allowing scientific testimony regarding truthfulnessinto evidence, is the court invading the purview of thejury?

Can you test defendants? Can you test nondefendantwitnesses?

Bias detection: can we test a jury to see if they will bebiased?

Should lie detection methods be used in courts?


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Can you beat a lie detector? There are three basic types of questions you will be asked: relevant, irrelevant, and

control. Dont admit anything relevant.

Say only what you need to. Yes orNo answers

Maintain a normal breathing rate of 15-30 breaths per minute but alter it during controlquestions.

Bite your tongue. Bite the side of your tongue hard enough to cause pain.

Insert a small nail or tack in the toe area of your shoe and press down on this during thecontrol questions to elicit a pain response.

Contract your anal sphincter muscle when a control question is asked (pressure-sensitive seat pads).

Your first impulse will be to try to conceal all emotion, but that is exactly what notto do.The physical effort required to conceal emotion shows up and could often be detectedwithout a machine. So, in beating the lie detector, intensify them as much as possible.

To confuse the test from the start, you might tense your muscles when the rubber iswrapped around your arm.

The way to beat the association test is simply to blurt out the first word you think of inassociation. The body was found in a park, so when one of the key words given you is"park," naturally the first word you think of, whether you're guilty or innocent, is"murder."

Seeing that you appear to be not afraid of his machine, the operator will be naive

enough to think you innocent.


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How to tell when someone is lyingGeneral Verbal Responses

May take longer to start answering

May answer to quickly or before the question is completed

Often ask the questioner to repeat the question or they repeat it themselves Overly polite or apologetic dialog

Persistent complaints

Unnatural silence

The Behavioral Clusters of Deception

Deceptive people follow certain behavioral patterns.

- Macro Patterns -

General Behaviors:

Increased discomfort and anxiety, hostility, unmerited anger towards you, persistent evasiveness, resistancePosture:

Early signs of extreme rigidity followed by alternating stiffness and relaxation. Hands, legs, objects put in front of body toform a barrier (folding arms, crossing legs, etc.). Feigned lack of interest. Posture changes caused by topic changes. Notfacing you. Distancing or leaning away from you.

Gestures and Movements:

Rubbing the forehead near the temple region. Squeezing the face, rubbing the neck, or stroking the back of the head withthe hand. Using fewer hand movements to illustrate their actions than usual. Movement away from you. Lip licking andhard swallowing. Wringing hands. Hiding the eyes

- Micro Patterns -expressed on the faceGeneral Expressions:

Averting the eyes. Focusing the eyes - some will try to stare down to show control. (A truthful person stares only half thetime on average). Face whitening.Face flushing.

Eye-Accessing Cues

By the direction of where the persons eyes are looking, you can determine whether they are using vision, sound orkinesthetic (feeling) to trigger their thinking.

Keep in mind that this is reversed for left-dominant people (left handers). So before you can use this, be aware of whichof their sides is the dominant one.


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Eye Movement


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How to lie The first thing you do when lying is to tell the truth -- not the whole

truth, but just enough to make the lie itself seem true. If you sense

that someone else suspects you of lying, admit to something small or

untrue. Think of some specific true thing (place, person, event, story)

that your lie will fit into and use those details if you are questioned.

This gives you a bank of specific details to draw on so you don't have

to keep making things up as you go along.

The trick is convincing your sub-conscious mind that you're telling thetruth. An example of this may be, "Did I wreck the car? Well, I drove it

into a wall. So, the wall wrecked the car. I just moved it!

Look the person you are lying to in the eye. Don't look around. Try

making your eyes go big and letting your mouth hang open a little for

an innocent/shocked look.

Never forget about your lie, and treat it like it actually happened.

Mention it in conversations the way you would if it was true. Silence

about a certain subject can arouse suspicion, especially in retrospect.

Use named, recognizable people.


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But most importantly

Always tell the

truth!


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Youre Detective Poly.1. Start with invasive CONTROL questions to begin to recognize

his/her regular behavior.YOU: What class do you have tomorrow?

YOU: Who is your favorite musician? Whats the favorite concert youhave ever been too?

YOU: What restaurants do you recommend? What kind of food do they

serve?2. Now lets get to the truth!! Here are some suggested ?sFeel free toask different ones, but the key is to probe.

YOU: Have you ever lied to your best friend? What did you say tothem?

YOU: Since youve been at Vanderbilt have you washed your bedsheets?

YOU: Where were you born? What was the name of the hospital?

YOU: In the past month, have you deliberately not answeredsomeones phone call? Who was the person?

3. DID HE/SHE PASS?


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Youre Suspect Suspicion

1. You will be asked a set of controlquestions first that you must answer

truthfully for the experiment

2. Let the lying begin! (Note: You mayanswer all of the questions right or all

wrong if you want. This might throw

Detective Poly off.)

3. Evaluation from Detective Poly

Lie Detection Final

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Transcript of Lie Detection Final