A running theme through the show Black Mirror are these small devices that people put on their temples. In one particular episode , an insurance rep is using the device, along with a little TV that shows what the person wearing the device is thinking, to get the details about someone getting hit by a delivery truck. I won't ruin the episode for you, but essentially someone tries to lie and they get caught because the insurance rep could see what they were thinking. How cool of a device would that be in real life?! The closest thing that humans have been able to come up with to detect deception thus far is the polygraph , which, although it's a cool device, doesn't do what it purports to do. The polygraph claims to be a lie detector test by measuring things like skin conductivity (sweat on your skin), heart rate, blood pressure, and breathing, and then the examiner interprets the results and decides if you were lying or not. The idea is that there are