PSYC1004 Lecture Notes - Lecture 3: Frontal Lobe, Prefrontal Cortex, Polygraph
Lecture 3
22 September 2017
09:06
Lying
Is there a neural pathway for lying
If we identify neural signatures of lying and psychological pathology, what are the ethical
implications of identifying such signatures
Is there a biological factor associated with lying
The polygraph - lie detector test
oUsed extensively in the past
oRelies on changes in heart rate, skin conductance (galvanic skin responsive) and
blood pressure
oThese physiological markers change in response to stressful events
oPolygraphs are not really used in the legal system anymore and are not admissible in
the court of law
oAlthough, there are some downfalls
Although the lying may not be stressful
Consciously supressing the physical response
You might be overly stressed anyway - being investigated for murder of
being accused of something you didn’t commit is highly stressful
What if the individual is delusional? They genuinely believe they didn’t do it
Individual being investigated has to also believe in the efficacy of the lie
detector
Pain induces the same response
Using biological factor to indicate lying
oSpitting out rice - dry mouth when you are lying - cant spit it out
Neuropsychology of lying
ofMRI and PET measure blood flow in the brain
oParts of the brain that are metabolically active
oWhen a part of the brain is working in response to some event,
oHard to control blood flow to certain parts of the brain
The Guilty Knowledge Test (GKT) Langleben et al 2002
oNormal participants
oWere given a card in an envelope
oAsked to lie in regards to having a particular card - if they fool the computer, they
can keep the money that comes with the card
oControl condition was responses to questions that required a truthful response
oThe prefrontal cortex
oThe frontal cortex
oThe anterior cingulate
oAreas of the brain known to be involved in things like:
Dealing with conflicting information
Inhibiting responses
Korzel et al 2005
oNormal subjects asked to "steal" a ring or watch
oAsked to lie about the "watch" or "ring" questions
oHad an added advantage of getting $50 if they could deceive the experimenter
oThis is what was different, good motivation to lie
oFrontal cortex
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Is there a neural pathway for lying. If we identify neural signatures of lying and psychological pathology, what are the ethical implications of identifying such signatures. Is there a biological factor associated with lying. The polygraph - lie detector test: used extensively in the past o. Relies on changes in heart rate, skin conductance (galvanic skin responsive) and blood pressure o o. These physiological markers change in response to stressful events. Polygraphs are not really used in the legal system anymore and are not admissible in the court of law: although, there are some downfalls. You might be overly stressed anyway - being investigated for murder of being accused of something you didn"t commit is highly stressful. Individual being investigated has to also believe in the efficacy of the lie detector. Using biological factor to indicate lying o. Spitting out rice - dry mouth when you are lying - cant spit it out.
