Why Are People Who Are Interested In The Paranormal Either Skeptics or True Believers?

 People pursue their interests and if they pursue the paranormal they rapidly decide to follow the conservative, skeptical route or the paranormal route based on their background beliefs.

Our background beliefs shape our perception and we try to have new information conform.

The effect of this is that we ask HOW can things that support our beliefs be true? We try to find ways to interpret information to support our beliefs and new ideas that would support our beliefs.

With ideas that contradict our beliefs we ask MUST this be true? We try to be especially skeptical about them and find any way possible to dismiss or doubt them.

These biases, along with many others, make it so we have extremely high confidence in our interpretation of reality as we have built up our belief in ideas we believe and torn down the belief in ideas we don't believe so we end up either very often string believers in the paranormal or strong believers that the paranormal are not true, or at least not supported by good evidence and so should not be believed in. 

Confirmation Bias - Can Versus Must

In the book The Righteous Mind author Jonathan Haidt outlined the essential experience of confirmation bias. He described how he has studied confirmation bias in people for many years (He has a PhD in psychology) and didn't really grasp it fully until his wife told him she has asked him to not put dishes in a certain place and he answered her then realized he had made an excuse that required combining bits and pieces from different events to create an exaggerated version of reality to justify his excuse.

Haidt described talking to his young son and realizing that if his son wants something he asks CAN it be done ? And tries to find any way possible that something CAN be how he wants it to be.

If he finds something he doesn't want he asks MUST it be this way ? Meaning is it absolutely necessary and unavoidable ?

We all tend to do this. If something fits what we want and is in agreement with our chosen behavior, thoughts and emotions we are eager to find and accept it and present a very low bar for considering information as correct and valid.

If something contradicts what we want and is in conflict with our chosen behavior, thoughts and emotions we are uncomfortable with it, it triggers cognitive dissonance and we become guarded and defensive and treat the disconfirming evidence as a threat and seek to negate, minimize or refute it as strongly and quickly as possible. It is treated as if it must be false and great efforts are made to find any way it could be wrong.