One big source of illusion (or "bias") is that we become attracted to our own theories as to what causes the things that we perceive--but our theorizing and perceiving .... science doesn't ask to be "believed in" as such. ... the given theory is useful as a basis for ongoing research until the next, better theory comes along.
(...)When it comes to creating observational bias, any idea that one has about "why X is happening" creates an expectation that "it is X which is occurring"--and this steers one to some extent toward perceiving the occurrence of "X" as we happen to define it, and away from perceiving whatever is inconsistent with "X". That's the opposite of what most people intend when we want to learn the truth about something.
one ... myths is that dynamic mics have a certain "range" close to the capsule and ... reject sound originating from beyond this range way stronger than condenser mics...