lie detector



in the early 1900s tests began measuring emotional conditions, Benussi was the first to study with these tests, he noticed the ratio changing in blood pressure.

In 1913 W.M. marston noticed there were definitent changes in blood pressure with criminals.To than figure out they where lying which in turn started the process of the detector

In 1921 larson used marstons theories against 4,000 criminals, to see if it actually worked seeing if they would prove they did what ever they did.


John larson had finally in 1921 finish the lie detector and released it but it tecnically was invented by James Mackenzie in 1902 but larson gets the credit.Because mackenzie never exactly finished it.

In 1923 it was first used in the frye vs united states case.To find out frye was lying about what he did and was put in jail.

Since 1924 police have been using the lie detector for investigations.Against thousand of criminals so they wouldn't have to do more work like they did before the detector.

Leonarde Keeler in 1930 helped set up a crime labartory for it in the northwest a year before the fbi.To make improvements to the detector and so there would be a place to test it on people.

But the lie detector isn't always right, in 2003 gary ridgeway the green river killer passed the test where a innocent man failed. The man was put away for no reason and gary got away til he finally just convinced he did it.

pictures from sentences

Big image

frye vs united states case

imporntance and consequces

The lie detector is very important to see if people are lying or to catch criminals, to help with court cases, it can also study our heart rates.

But lie detectors can be very wrong at times police could be locking up the wrong person because it didn't work right, it was bad for criminal organizations because they weren't able to lie and were put in for more time for lying


Wikipedia. Wikimedia Foundation, n.d. Web. 29 Sept. 2015.

"History of the Lie Detector or Polygraph Machine." Inventors., n.d. Web. 29 Sept. 2015.