These slides are all about an instrument called lie detector.

1. B121635
B121582
Lie
Detector

2. Contents
- General idea about lie detector.
- How does it really works ?
- Do the lie detector really accurate?
- How will be the questions of investigator.?
- Can we fool the lie detector machine ?
- It is legal or illegal ?

3. Signs that a person is lying
- First of all a lie is a false statement or give a wrong
impression to someone.
- Nervous smiling.
- Prounciation mistakes.
- Facial and body Responces.
- Eye contact.
- Timing and unnatural silence.

4. Do you think it is really exsists?
- Lie detector is a instrument which detect whether the
person telling lies or not.
- A polygraph is a combination of medical devices that
are used to monitor changes occurring in the body.
- It monitors and give the graph of pysiological
reactions

5. Invention
- First polygraph test conducted during the world war I in 1917. But
it is not very much success.
- New model of polygraph was invented in 1921 by a medical
student of california university john agustus larson.
- At the time of world wars berkeley police department suggested
him to invent.

6. How does it really works ?
- By observing physiological
reactions like
-Heart rate
-Respiration rate
-Electro thermal activity
-Change in blood pressure
-skin conductivity
-eye movement

7. How to set up polygraph test?

9. Observing results
- It depending upon investigator only.
- Experience of investigator is most
important thing.

10. Medical kit
- Body movement sensors
- Electrocardiogram
- Galvanic skin resoponce sensor
- Skin sensors

11. Interrogation questions like
- Start with control questions to recognize regular
behavior.
- After contro questions he gets to truth.
- What restaurants do you recommend? What
kind of food do they serve?
- Have you ever lied to your best friend? What
did you say to them?
- In the past month, you not answered someone’s

12. What is validity of lie detector???
- Just 85 to 90% accurate,not more than that.
- Its depends upon the comparing results also.
- Mostly depends upon the person character
* Innocent or not.
* Open himself or not.
- Depends upon examiner also.

13. - Say only yes or no answers.
- Breathe normally.
- To confuse the test from the start, you might
tense your muscles.
- Answer questions directly and seriously.
- Seeing that you appear to be not afraid of his
machine.
- Answer control questions strangely.
Can you beat a lie detector?

14. Legalities
- Rarely admissible in court
- New Mexico is the only state that allows for open admissibility
of polygraph exam results.
- First time in 2008,once polygraph used in court in india
- In 2010 Supreme court of india declared polygraph tests are
against to the constitution.

15. Used as
- Police department is used as investgation tool.
- Others are used to detect someone is lying or not. .
- Faster public confidence on in law enforcement.
- National security.

16. Thank you very much