Perception barrier

A perception barrier was a field that affected the perception centres of the brain. According to the Third Doctor, it told you "Nothing to see here, move along."

It was not particularly effective against determined or immature minds.

Around the 1970s, a group of Armidians in Portsoy placed a perception barrier around a fishing shed containing a missing RAF jet fighter, and around the dilapidated house on a cliff they were based at. (AUDIO: Vengeance of the Stones)