Here is a quote from an article about consciousness

    "One of the processes important in perception is the comparing of current input with similar past experience.
    When we see a friend, a memory image of his face is presented to our consciousness along with the
    sensation of his actual present appearance.
    This memory image (which can be called a schema) blends with the current sensation, so that the
    perception is a combination of the two. The relative strengths of each source of information probably 
    vary from person to person."

It not scientific or proven true. It does however work as a model for a part of peoples perception that fits quite well to peoples behavior.