News organs would do readers a valuable service if, whenever they report that someone has taken or proposes to take a polygraph, they reminded readers (or explained to them) that polygraphs are voodoo. It's junk science. A polygraph is no more reliable than a pack of tarot cards.
Papers that report that Mike Pence has offered to take a polygraph or that Christine Blasey has taken one without explaining that polygraphs do not work are wasting an opportunity to enlighten their readers. It's their choice, but it's an irresponsible one.
If you promulgate the idea that there's a machine that can tell the difference between truth and falsehood, you shouldn't be so surprised to find yourself living in a culture so hostile to science that kids go unvaccinated and measles breaks out in the First World.
A polygraph measures your heart rate, breathing, and galvanic skin response. If you convince suggestible people that these measurements are associated with lying, they are more likely spontaneously to confess when you tell them, "The machine says you're lying."
That's the value of a lie-detector test. It can be a useful interrogation tool if you're dealing with someone who believes it works. But it actually cannot tell the difference between truth and falsehood.
People can be trained not to crack upon interrogation. If it's administered by someone friendly, there's no interrogation at all. So anyone Mike Pence or Christine Blasey hires to administer a lie-detector test will of course discover that he or she is telling the truth.
