How does a lie detector work?

Question

Did you ever see a television show where you take a lie detector test to see who "really is the father"? Or maybe The Moment of truth. When I watch these shows I often wonder, how does this lie detector work? How does it know if it's the truth or a lie? Answers anyone?

Answer 1

Good question--Here's my take on it--- Supposedly, when the electrodes are hooked up to certain pressure points on your body, the device can detect slight changes in heart rate, pulse, etc. After detecting the HR and pulse at rest, the machine dubs the constant output, establishing a standard. It uses this as the participants "norm". It  notes slight changes to this "norm", and can measure the extent of the  physiological changes associated from a certain question. This really leaves no room for doubt, as there seems to be no established standard deviation.

Example:You are take a lie detector test, and when asked if you are a good person, you believe you are telling the truth when you answer "yes". The machine notes perhaps anxiety or nervousness, which can cause slight physiological changes that you might not have noticed.  Thus, the  examiner determines you were telling a lie.

Answer 2

its all about how nervous you are.

Answer 3

It is basically a heart monitor.  If you are connected to the detector and you answer a question with a lie, your pulse will speed slightly.  They work on most people, however politicians are immune :)

Answer 4

it is how fast your heart is pacing. a lot of people can get past one of the most complex detector by being able to control the emotions, and heart rate. so basicly they stick stuff on you that can sense your heart rate. then it sends electronic signals to the main system. the main system then make the little wire like thing that goes crazy when you tell a lie..well...GO CRAZY!! and that is how it works. all the stuff is documentized on a long piece of paper or done on a computer.

Answer 5

by the peak or tone in your voice