Six Thinking Hats was written by Dr. Edward de Bono. "Six Thinking Hats" and the associated idea parallel thinking provide a means for groups to plan thinking processes in a detailed and cohesive way, and in doing so to think together more effectively. Underlying principles The premise of the method is that the human brain thinks in a number of distinct ways which can be deliberately challenged, and hence planned for use in a structured way allowing one to develop tactics for thinking about particular issues. De Bono identifies six distinct directions in which the brain can be challenged. In each of these directions the brain will identify and bring into conscious thought certain aspects of issues being considered (e.g. gut instinct, pessimistic judgement, neutral facts). Some may feel that using the hats is unnatural, uncomfortable or even counterproductive and against their better judgement. A compelling example presented is sensitivity to "mismatch" stimuli. This is presented as a valuable survival instinct, because, in the natural world: the thing that is out of the ordinary may well be dangerous. This mode is identified as the root of negative judgement and critical thinking. Colored hats are used as metaphors for each direction. Switching to a direction is symbolized by the act of putting on a colored hat, either literally or metaphorically. This metaphor of using an imaginary hat or cap as a symbol for a different thinking direction was first mentioned by De Bono as early as 1971 in his book "Lateral Thinking for Management" when describing a brainstorming framework. These metaphors allow for a more complete and elaborate segregation of the thinking directions. The six thinking hats indicate problems and solutions about an idea the thinker may come up with. Similarly, "The Five Stages of Thinking" method—a set of tools corresponding to all six thinking hats—first appears in his CoRT Thinking Programme in 1973: Strategies and programs Having identified the six modes of thinking that can be accessed, distinct programs can be created. These are sequences of hats which encompass and structure the thinking process toward a distinct goal. A number of these are included in the materials provided to support the franchised training of the six hats method; however it is often necessary to adapt them to suit an individual purpose. Also, programs are often "emergent", which is to say that the group might plan the first few hats then