The overriding strength of vision over comon sense

 The power of the visually oriented processing of the human mind has plenty of positive attributes, seeing as the most sensitive and complex sense we possess is our sight, but that same complexity lends to its negative effects as well. The brain can collect a significant amount of information from our eyes, information that could save our lives. For instance, most poisonous or foul tasting insects are brightly colored and vividly patterned. Yet, the same visual information that we receive can fool our common sense, as well as trick us into believing things that aren't true. 
     The following video is a demonstration of how the brain can be fooled so easily by the simplest things as long as the stimuli correspond, even though you know full well that you're not in any danger.

http://science.discovery.com/videos/through-the-wormhole-the-dollhouse.html