If you don't see much of pay-TV's "factual" channels – History, Discovery and the like – you might assume that they're full of dull but worthy, meticulously researched documentaries about the history of the Third Reich and the mating habits of the spotted hyena. If only!

As often as not, the schedules are a cascade of codswallop about Bigfoot, ancient aliens, chupacabras, ghosts and mermaids. It's as if there's some kind of charter stipulating that every half-decent fact-based program must be balanced by a pile of cynical, insulting paranormal-related garbage. Whether it's aliens genetically engineering sasquatches to serve as slave labourers or household pets being able to sense the presence of demons fresh out of hell, nothing is too stupid to be packaged up on the cheap and foisted on credulous viewers.

"So what?" you might think, "Nobody believes that sort of nonsense." But they do. When Discovery aired Mermaids: The Body Found – a fake documentary pretending that governments around the world are conspiring to keep the existence of mermaids a secret – so many Americans believed it that the US National Oceanic and Atmospheric Administration felt compelled to issue a statement explaining that mermaids aren't real.

For someone to be able to identify and dismantle pseudoscience or pseudohistory they need a basic knowledge of science or history to begin with, but too often the very channels that used to provide such knowledge are instead obscuring and undermining it with blatant nonsense presented as truth.