If we want to detect recognition of something they deny, we can go directly to the brain: https://www.psychologicalscience.org/observer/detecting-dece...

Michael from VSauce already tried to countermeasure this method and failed.

https://psychology.iresearchnet.com/forensic-psychology/poli...

https://www.sciencedirect.com/science/article/pii/S001002770...