Neil Postman

[...]it seems clear from the Ames studies that what we perceive is largely a function of our previous experiences, our assumptions, and our purposes (i.e., needs). [...] You tend to perceive what you want and need to perceive, and what your past experience has led you to assume will “work” for you. Third, we are unlikely to alter our perceptions until and unless we are frustrated in our attempts to do something based on them. If our actions seem to permit us to fulfill our purposes, we will not change our perceptions no matter how often we are told that they are “wrong.”[...] This does not mean, however, that we automatically change our perceptions if we are frustrated in our attempts to act on them. This does mean that we have available the alternative of changing our perceptions.