Deception Detection Flashcards
Concern Approach
Threat or anticipation of trouble leads to physiological responses that are detected by the polygraph.
Control Question Technique
Based on concern approach. Initial discussion, simulation test to trick suspect into believing the polygraph. Then ask neutral, relevant and control questions. Control questions make the person look bad but are unrelated to the event.
Innocent - bigger reaction to control
Guilty - bigger reaction to relevant
Critiques of CQT
Control questions difficult to create (can’t be too threatening or too tame), deliberately deceiving suspect (simulation test), high error rate for innocent people (relevant question may provoke bigger response that control)
Orienting Approach
A word or phrase that is recognised will generate a physiological reaction that can be detected by the polygraph.
Guilty Knowledge Test
Based on orienting approach. Uses information only police and offender would know. Read a list and have suspect answer no to each one. If guilty, there will be a spike to the target word because the recognise it.
Critiques of GKT
More ethical and valid than CQT. Can also beat countermeasures by making them memorise a list of words. However, difficult to do because specific information is needed. Response may occur for other reasons (eg favourite colour). High error rate for guilty people.
Countermeasures
Techniques that can be used to increase baseline response or decrease response to target items in order to beat a polygraph. Eg thinking about being slapped or scrunching toes, or singing a mental song of counting sheep.
Thermal Imaging
using a heat camera to detect temperature changes in the face that occur when lying. However, measures anxiety and people can be anxious about other things.
Event Related Potential Analysis
Measures electrical impulses in the brain. More objective version of GKT. However, countermeasures can be used and has same issues as GKT.
fMRI Scanning
Measuring changes in neural activity and blood flow. If lying, should see prefrontal activity and activity in reward/consequence pathways. Good accuracy and harder to use countermeasures, but pattern can vary depending on whether the lie is novel or rehearsed, it is expensive and there are legal issues.
Improving Deception Detection
Markers are not very good. Need to increase cognitive load of suspect (reverse event order, ask unanticipated questions about time/spatial orientation) and use evidence strategically. Cognitive load increase will lead to more errors and pauses and possible mistakes and inconsistencies in story.
Good Liars
Have good memory, reduced emotional responses, acting skills, are well prepared, can think quickly and speak well to stall for time.
