Detecting Deception

Steven Van Aperen

Australian Polygraph Services

23rd November 2006

All truths are easy to understand once they are discovered; the point is to

discover them.

Galileo Galilei

It is very difficult for theaverage person to lie.

Why do people deceive?

Conditioning

To hide the truth

To protect themselves

Types of lies

“I wasn’t involved in match fixing, I always played to win”

“I studied psychology at University”

“I did not have have sexual relations with that woman Monica Lewinski”?

Lying in Employment

One third admitted to lying on CV47% lied about leisure pursuits28% about their salary19% about personal skills & qualities3% about criminal record

Lying in Employment18% think its necessary to lie on CV’sOne fifth believe employers don’t check6% say that they would just say they made a typing error!30% admit to lying but managers think only one in ten (10%) CV’s contain false information 36% believe it is the responsibility of employers to check accuracy

What to look for:

Paralinguistic ChangesNon-Verbal (Body Language)Verbal (Lying with words)

What to look for:

TonePitchRateResponse Latency

Non-Verbal Behaviours

Look for clusters of behaviour Be aware of hand to face gestures

Non-Verbal Behaviours

Research indicates that up to 80% of communication is non-verbal

Non-Verbal Behaviours

Remember our body language will often betray the spoken word.

(Yes/No)

The eyes have it, or do they?

The Qualifying Statement

The subjects response may be literally true because they deny some narrow issue of the interviewer’s question

Lying by generalisation

Often a person will lie by generalisation. This occurs when a person may be vague or non-specific in response to a question.

Verbal Responses

Truthful people answer specific questions with

direct, spontaneous and realistic words

Examples of how people deceive

Analysing content and structure

PN: They’re now with you are they? MB: Yeah I’ve actually transported the female, Sally.

MB: Um ah yes she’s asl um she’s half asleep anyway

Police negotiator (PN) and Martin Bryant (MB)

28th April, 2000 re Sally Martin

PN: She’d be very frightened and she’s an elderly lady.

MB: Yeah I got her upstairs so

PN: So you can imagine that the trauma that she’s going through

MB: She’ll be fine I mean they could eat well

Police negotiator (PN) and Martin Bryant (MB)

28th April, 2000 re Sally Martin

PN: Are you prepared to let me talk to Sally

MB: Ah unfortunately um she’s down stairs with David now I’ve got um another chap with me.

Police negotiator (PN) and Martin Bryant (MB)

28th April, 2000 re Sally Martin

Past & Present Tenses

Singular person past tense vs present tenseLook for changes between past and present tense

It was Monday night. I was walking down the road. It was getting dark when a man ran up and punched me in the faceIt was Monday night. I was walking down the road. It was getting dark and a man runs up and punches me in the face.

Susan Smith 25th October, 1994

• “My children wanted me. They needed me. And now I cant help them.” Susan Smith (mother)

• “They’re OK. They’re going to be home soon.” David Smith (father)

Shapelle Corby “I didn't put it there” (4 times)

“This is not mine”

“I'm innocent” (twice)

“I didn't put it there that’s the bottom line I didn't put it there.”

“They're not my drugs. I didn't put them there.”

“I’m innocent.”

John Myles Sharpe plea for the return of Anna Kemp & Gracie Sharpe

Did you kill your wife and daughter?

•“I haven't harmed my wife or my daughter”

•“The child belongs with the mother”

SummaryLearn to understand and read body languageAre questions being answered or is the person being evasive, omissive or dismissive?Observe what the person is doing as well as listening to what they are saying

SummaryLook for changes between past and present tensesLook for ‘clusters’ of behaviourRemember we lie by omission rather than commissionPRACTICE!