Could It Be a Sham?

i'm sure scientists doing this are responsible and know what they're doing, but just tell us some of the evidence that makes it clear that these people truly are in rem sleep. They're not sort of playing games with us, being awake but pretending to be asleep. How do we know they're really asleep? One of the key features of rem sleep is this motor paralysis. An you can monitor the motor paralysis. And this has been done ever since sleep physiology has been studied in the labs.