Methods of lie detection SYNOPSIS Polygraph Brain mapping / brain fingerprinting Narco – analysis ( truth serum drugs ) POLYGRAPH Instrument used to detect lies Records BP, pulse rate, respiration & electro dermal reaction changes in response to questions asked QUESTIONS FRAMING Framed with mutual consent from suspect and the examiner Yes or No type questions Question asked every 20-25 seconds Test repeated 2 or 3 times BRAIN MAPPING / BRAIN FINGERPRINTING NARCO-ANALYSIS SUMMARY Polygraph – records BP, pulse, respiration and electro dermal reaction changes in response to questions Brain mapping – records changes in intensity of brain waves in response to questions & visuals Narco analysis – truth serum drugs are given – suspect incapable of resistance - reveals guilty actions and repressed memories when he reaches a state of relaxation THANK YOU

1. METHODS OF LIE DETECTION
R.Aiyshwariya
2nd year MBBS
Govt. Theni Medical College
FORENSIC MEDICINE

2. SYNOPSIS
O Polygraph
O Brain mapping / brain fingerprinting
O Narco – analysis ( truth serum drugs )

3. POLYGRAPH
O Instrument used to detect lies
O Records BP, pulse rate, respiration & electro dermal
reaction changes in response to questions asked
O Basis
Person tells a
lie in answer to
a question
Fear of getting
caught causes
sympathetic
nervous system
stimulation
Increase in the
parameters
mentioned above
Recorded by
polygraph

5. QUESTIONS FRAMING
O Framed with mutual consent from suspect and the examiner
O Yes or No type questions
O Question asked every 20-25 seconds
O Test repeated 2 or 3 times

6. BRAIN MAPPING / BRAIN FINGERPRINTING
O Basis
EEG of suspect recorded
visuals from SOC shown
when visual matches with
information stored in the brain
intensity of brain waves
recorded will increase
ELECTROCAP
TO RECORD
EEG

7. NARCO-ANALYSIS
O Basis
½ mg scopolamine hydro bromide s.c. /
Sodium amytal / Sodium pentothal i.v.
1ml per minute
Suspect reaches a stage of relaxation /
near unconsciousness
Incapable of resistance to questioning
Reveals guilty actions, repressed
memories and feelings

8. SUMMARY
O Polygraph – records BP, pulse, respiration and electro
dermal reaction changes in response to questions
O Brain mapping – records changes in intensity of brain
waves in response to questions & visuals
O Narco analysis – truth serum drugs are given – suspect
incapable of resistance - reveals guilty actions and
repressed memories when he reaches a state of relaxation

9. THANK YOU