Edward de Bono has written numerous books about thinking. One of those books is Six Thinking Hats. Each of the six hats represents a different approach to the thinking process.

Information: (White) - considering purely what information is available, what are the facts?
Emotions (Red) - instinctive gut reaction or statements of emotional feeling (but not any justification)
Bad points judgment (Black) - logic applied to identifying flaws or barriers, seeking mismatch
Good points judgment (Yellow) - logic applied to identifying benefits, seeking harmony
Creativity (Green) - statements of provocation and investigation, seeing where a thought goes
Thinking (Blue) - thinking about thinking
(from Wikipedia )