lie detection Flashcards
Polygraph Test
Measures physiological responses
Polygraph Physiological Responses
- Blood pressure
- Heart rate
- Breathing rate
- Galvanic skin response (GSR)
GSR (Galvanic Skin Response)
Amount of current conducted by placing two electrodes on the skin (higher reading produced)
Activation of the Sympathetic Nervous System
Increased Sweat (GSR: increases electric currents produced)
Limitations of Polygraphs
- Assumes lying causes physiological arousal
- Assumes a person who lies feels guilt and will have a physiological reaction
- Only detects physiological responses
- Emotions cause the same physiological responses
Concealing Knowledge (Polygraph)
Causes a change in physiological response which the polygraph will detect
Recognition
Harder to hide than fear or guilt
P300 brainwave
Electroencephalograph (EEG)
Records brainwave patterns (P300 response cannot warrant guilt)
Functional Magnetic Resonance Imaging (fMRI)
Detects frontal love ant ACC activity
Lying Activates
Frontal lobe and anterior cingulate cortex (ACC) more than other areas
fMRI and Guilty Knowledge Test
- Increased likelihood of detecting a lie
- Damage to the frontal lobe (anti-social personality disorder) shows no increased activity (unreliable)
Heat Sensor Camera
Senses increase in blood flow to the eyes (occurs when someone is lying)
- Quick to administer, easy to read
Research in Lie Detection
Current Research: Experimental conditions in a lab which might not reflect real-world situation