February 07, 2006

Looking for lies in all the wrong places

The following guest post comes from the distinguished sociolinguist and forensic linguistics expert Roger Shuy:

Mark Liberman's comments on the New York Times article "Looking for the Lie" reminded me that there are scads of programs offered to law enforcement agencies around the country, all of which claim to teach cops (and anyone else willing to pay the tuition) how to detect deception.

Avram Sapir's Scientific Content Analysis (SCAN) program is one of them. Curious about it, I paid my $350 and took his week-long seminar about a ten years ago. It's an odd mixture of the techniques used by the FBI, called Statement Analysis, and a hopeful but largely misguided use of some of the good work coming out of Paul Ekman's laboratory in San Francisco. Mix in a touch of the Reid Technique, stir well, and you can teach the police how to tell when suspects are lying.

I found SCAN, Statement Analysis, and the Reid technique amusingly optimistic and often downright frightening. But they are hot items in our nation's police departments.

Perhaps SCAN's best attribute is that it begins by admitting that the police interview often messes up royally (I wondered then, and still do, why then it might not be better to try to improve the interviewing). To avoid this problem, Sapir suggests that before the interview begins, the police are to give the suspects pen and paper and have them write a description of everything that happened on the theory that it's much harder to write a lie than to say one. He also teaches that people lie indirectly, so the police are to notice omitted information, hedging, answering questions with questions, and ignoring certain things. Some (but by no means all) of his principles include the following highly suspicious conclusions:

  • The shortest way to write a sentence is the best way. Any deviation from short is meaningful.

  • Changes in language reflect change in reality, with examples such as changing "my wife" to "Louise" or changing "my son" to "my child".

  • Information that comes as an answer to a question is less reliable than information that comes without being asked.

  • Nobody can lie twice, which means that it is impossible to lie on two different layers of deception about the same issue. It is also impossible for a deceiver to say, "I'm telling you the truth."

  • The sequence of the statements reflects a deceiver's priorities. Sapir says that there are three time units to be described: before, during and after the incident. 85% of deceivers are said to devote more writing to what happened before and after the event.

  • Pronouns produce 80 to 90 percent of the deception. When "I" is changed to "we", this indicates that there is deception. The lack of "I" indicates that the subject might be lying.

  • Changing "my" to "the" is also a key.

  • The unnecessary use of connectors such as time markers are signs of lying because they replace information that the deceiver left out of the statement.

  • After reviewing the writing, the cops can interview the suspect.

Statement Analysis does much the same. Again using a written statement, the analyst looks for these clues to deception: overly detailed statements, repetition, unusual details, unnecessary complication, irrelevant details, subjectivity, admitting memory loss, hedging, excessive self referencing, verbosity, unnecessary connectors, deviating pronouns from "I" to "we", and the imbalance of language on the beginnings and ends of the statements.

If you are still bothering to read this, an even greater surprise is in store for you. The Reid technique, developed by John R. Reid of Chicago's Scientific Crime Detection Laboratory. Unlike Statement Analysis, it takes allegedly known information about verbal and non-verbal communication and uses it during the police interrogation. The cop is to ask a set of 15 questions, noting throughout such non-verbal features as nervousness, body twitching, lack of eye contact, downward glances, eye blinking, and arm flailing. As for language clues to deception, long pauses, overly elaborated responses, off-topic responses and silence are all diagnostic clues. The interviewers are to watch for these responses at the same time they do their interviews, marking the answer to each question with a slots marked Deceptive, Truth or Don't Know.

These techniques are not only highly suspect but they also make no allowance for the cultural, social or individual differences of the suspects. The police are expected to do more than is humanly possible, such as watching for the frequency of eye contact (truth tellers are supposed to do this between 30 to 60 percent of the time). One wonders how this could possibly be measured on the spot. And nothing is said about the strong probability that it is the interviewer who stimulates the alleged clues.

— Roger Shuy

Posted by Geoffrey K. Pullum at February 7, 2006 09:27 PM