In the video above the principal is demonstrated rather effectively. We are shown an image of an old man with a crooked smile. When the clip of the man smiling is juxtaposed with a mother and child, we see it as a kind, compassionate smile. When the same clip of film of the smiling man is juxtaposed with a woman in a bikini our opinion of the mans smile changes. It is now creepy, and crooked.
This speaks volumes about how viewers make meaning. We are conditioned to see compassion when we associate the role of motherhood and the mans face. When we see him smile at a scantily clad woman, our opinion changes as it is not a societal norm to gawk at women with the intention of desire. Even in this clip, we know its an experiment. We know the man as probably looking at neither the mother or the other woman when this clip was shot. Yet, we can't hep but try to extend the meaning from one shot to the next.