You see lie detector tests used all the time in the movies. But just how realistic is this portrayal of polygraphs — especially under Pennsylvania law?
While some criminal suspects will publicly announce that they will take a lie detector test to prove their innocence, these boasts are largely empty. In addition, even if they undergo these tests, the results are dubious at best.
Still, law enforcement personnel will sometimes use lie detector tests. Here a look at how polygraphs are treated in Pennsylvania, as provided by the Pennsylvania Attorney General.