The mind is easily influenced by others—and by itself. In addition to being open to presuppositions, our minds regularly delete information and create distortions and generalizations by changing things and “filling in the blanks” when information is lacking.
While the human mind is able to process a seemingly infinite amount of information at the subconscious level, it appears to be limited to processing between five and nine (seven, plus or minus two) chunks of information at the conscious level at any given moment in time.