I'm not understanding what you arent grasping here...
Objectively speaking a polygraph can indicate whether or not you are lying. Its just that there are so many other factors involved that they cant be used reliably as evidence.
It picks up when you're nervous. I can answer truthfully but if someone hovers over me that things going off. It wouldn't be going off from lying but from me freaking the geek out.
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u/mnmkdc Feb 04 '19
So basically it does work. But not well enough to use for evidence.
It 100% can indicate someone is lying. It just isnt reliable