AP looks at a range of 'anomalistic' phenomena (things that don't seem to fit in to the generally accepted scheme of things, including but not confined to, 'the paranormal'), but starts from the assumption they are mostly explicable by conventional science. Instead it holds that the really interesting question is not, for example, 'do psychic gifts exist?' but instead 'why are so many people convinced that they do?'
Please don't misread that last sentence - I am not making an arrogant and closed-minded assumption that people are deluded. I think that beliefs in, for example, telepathy, dowsing and energy-healing, are not at all foolish, but are profoundly natural and do in fact reflect the way we experience the world. That does not mean that they are true in a scientific sense: in fact it seems that, when you chuck a bit of scientific method at them, the unexplained phenomena vanish. (What's left over is often very interesting though, even if not quite so flashy).
"Perception is theory-laden" - any psychologist will tell you that. It means that there is no hard distinction between perception and interpretation. So if I say "no that wasn't actually telepathy you experienced", you hear it as "you don't know your own feelings" (grossly insulting and implies incompetence or lying) rather than "you've made a very natural mistake" (debateable but neutral). I think this explains some of the heat that gets generated in this area of study. And I can be just as bad as anyone (a man's best friend is his dogma) which is why I make a point of trying not to take things too personally. I also try to be polite (this doesn't come easily) because indignation has a sweet pleasure all its own and can be indulged for its own sake.