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Lecture 7

Lecture 7

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PSYC 2400
Adelle Forth

Lecture 7—Polygraph: Lie Detector? Tuesday, January 25, 2011 - Experimental research on false confessions, polygraphs- today - Guest speaker- malingering mental disorders- Thursday - Will finish Ch. 4 next Tuesday, and start eyewitness testimonies *Questions - 1. The main issue in the case Brown v. Mississippi (1936) was: o a) use of physical coercion to obtain confession - 2. During an interrogation an innocent suspect confesses to a crime because they are told that members of their family will be harmed if they do not confess. This is an example of a: o e) coerced-compliant false confession - False confessions in the lab o One of the first studies done on false confessions- Kassin and Kiechel’s computer key study o Very little research has been done in this area- lots of open spots for employment- difficult to research o Asked to come to lab, deception was used (told to type letters quickly- measure of reaction time)- someone else arrived at the same time, but he/she was a confederate o Tester had to read out loud the letter while you type them o *Manipulated how plausible a mistake might be made—read letters quickly or slowly o Letter Z came up- computer crashed o *Warned you beforehand not to hit the alt button (adjacent to Z)—possible your finger slipped  If you hit Alt button, all data will crash and you will lose data o Suspect was accused of messing up experiment o *Vulnerability was manipulated as was the presence of false evidence  Confederate was “waiting for next turn”—said he/she saw the suspect hit the key vs. didn’t see anything o *Fast pace- more likely to make a mistake o Recorded four things:  1. Sign this confession to say you hit the Alt key—false confession • If you were in fast pace and confederate said he/she saw you do it, 100% signed false confession  2. Internalization- experimenter left room, next subject came in (another confederate)- I heard something happen from the other room. If participant said he/she hit the wrong key in the experiment, he/she is taking ownership. • Not as high as signing false confession • But still, in fast condition with false evidence, said he/she did something wrong • *This has nothing to do with the experiment- actually believes he/she did it  3. Confabulation- grad student came back and printed off the list of numbers the suspect typed in- come in and explain how you made that error—confabulation is making up a story about touching the Alt key (looked up and finger slipped, etc.) • *Most related to false confessions • *35% of students confabulated • *False evidence played a big role in this o Factors: manipulated false evidence, typing fast/slow—measured false confession, internalization, confabulation - Experimental false confession paradigm: important factors (Klavier et al., 2008)- SFU o Interested in different factors (no false evidence, witness, typing pace)- same scenario o Suggestibility Scale (book)*-- how suggestible you are to misleading information  How likely you are to incorporate misleading information  One of the only scales with reliability/validity in this context o Used minimization and maximization techniques o Typing letters on computer o *Plausibility varied—either accused you of hitting Alt or Esc key o *Also manipulated plausibility by asking you to go fast or slow o Mini-interrogation  Minimization: I know it was just an accident, several people before you made a similar accident.  Maximization: I’ve run 50 people in this experiment. Not one has screwed up the way you screwed up. Why did you do this? o *Low plausibility would still sometimes sign false confession, but none of them internalized (confederate walked in door, asked what happened) o *High plausibility increased likelihood of confessing, higher rates of internalization  Also interesting: most of them were more susceptible to minimization techniques o *This study has not been replicated. Hard to determine how it would apply to real world  Here, all suspects are innocent. Hard to relate to real world when some are guilty  Also, there are no consequences in this study.  The stress would go up a little in study, but not the magnitude of stress you would feel if you’re isolated and being accused of crime  Length of interrogation was only 20 minutes (not like 18 hours)  Threats were minimal o But it’s very difficult to get sources of data from real world - Polygraph o History of using physiological measures to determine whether someone is lying or not  China: suspects on the stand chew dry rice, spit it out. If the rice is still dry, you’re guilty (if you’re anxious, mouth will go dry).  Marston-1917: first attempt in NA to use physiological measures as lie detector- based on blood pressure • Frye v. United States- Frye killed physician, charged with nd 2 degree murder • His defence hired Marston to do a polygraph to see if he was guilty or innocent • Defence tried to call Marston to the stand- conclusion: Frye was innocent • Ruling: this blood pressure test did not have sufficient scientific reliability, would not be admitted to court • **Frye standard: whether something new can or cannot be admitted to court o Wonder Woman- Lasso of Truth  Marston wrote this Wonder Woman comic strip- she captures you, asks you questions with the lasso, must tell the truth o Polygraph- writing many o Physiological tool, measures physiological changes  First- blood pressure  Later- included other measures • Respiration, skin conductance, amount of sweat on skin o Polygraph examination combines polygraph and interrogation- looking at responses to specific questions o Originally was small, could fit in briefcase so examiner could take it anywhere, set up a polygraph o Used to include little pens that would print out responses—now it’s digitized (in laptop computer) o Measure chest (respiration)—things set around chest in upper chest, across stomach (because some people breathe more from chest/stomach) o Photo cell on finger for blood pressure/cuff o Electrodes on palms/fingers for skin conductance (sweat) o Example of polygraph exam  2 respiration channels (upper chest and stomach)—took a small second breath, held breath, etc.  Electrodermal activity (sweat on skin)—at question 9, huge jump in waves- large skin conductance response (this was at the same time as holding the breath)  2 blood pressures (hard to see change)  Could compare responses for questions 8 and 9- look at questions, try to decide whether person is innocent or guilty - *Question* o * If you were accused of a crime, would you be willing to take a polygraph to clear yourself?  A) Yes  B) No  C) Depends on if I am innocent or guilty o 24% said yes, 59% said no, 18% said depends o *It might help you get out of interrogation, though it wouldn’t finish the case and prove you innocent - *What is the key problem with using a polygraph? o Physiological responses vary if you’re just anxious or nervous (though not guilty)- would give the wrong idea o You’re being accused—feel fear- could also mimic the feeling of anxiety o There may be some personality types that are cool, calm and collected- don’t feel remorse- would pass the test even if they’re guilty - Black pad- put it under feet, you sit on it—measures shifting in seat/shifting of feet- would also notice if you clench your butt muscles - Uses of polygraph o Not admissible in Canada  R v. Béland, 1987 • 3 people plotting armed robbery • 2 people ratted on other 2 • Defence wanted polygraph on others to show they were lying • Not accepted in Canada o Varies in U.S.  In many states if the prosecution and defence agree, it can be entered in the court  But if the defence says no, the prosecution can’t enter it in court o Not admissible in U.K. o Police investigations o Employment and screening  Used to be used a lot, particularly in US  Polygraph Protection Act in 1988 (banned)  Before then, if you were applying for job, you would have to take polygraph- HUGE market- lots of work  Not for specific incident, like police investigation—asking questions about drinking on the job, stealing from employer, whether he/she abuses sick days—general character  Now it’s still used for some employment screening, but for particular jobs—RCMP, CSIS, FBI, CIA, etc. - Polygraph: use with sexual offenders o Treatment  Most of offenders will deny/minimize number of crimes they commit  Average number of offences were 12 pre-polygraph  After polygraph- said 12 (lying)- 15 (lying)- 20 (lying)- kept on going  Average number across the sample went up to 137 after polygraph  But maybe the 137 is an overestimate- the offenders want to get out of the investigation so they give a big number  Mainly in the States o Monitoring offenders  After they get released into community, conditional release (parole)  Every six weeks, take a polygraph  Examiner asks whether the offender’s been to a public swimming pool, associated with minors, had deviant sexual fantasies, etc.  If they’re deemed deceptive, phone parole and say the client is violating conditions  This is in the States- very popular o Study by English et al.  Like the treatment issue
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