The problem is that people know much more than they can tell; in other words, there
is dissociation between the cognitive process itself and a person’s ability to report on
that cognitive process. Conversely, people also claim to know more than they could
possibly know and/or misinterpret what they do know. For example, studies have
shown that customers frequently evaluate the quality of merchandise that they have
never used; in making such an evaluation, they take into account such factors as the
item’s position in a display, without mentioning (or even realizing) that the position in
the display has been an influential factor in determining their evaluation of the
presumed quality of the item (Nisbett and Wilson, 1977). In short, customers are
sometimes unaware of the stimuli of their responses and how these stimuli have
influenced their responses (Cialdini, 1993).