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). None of these directions are completely natural ways of thinking, but rather how some of us already represent the results of our thinking.
Since the hats do not represent natural modes of thinking, each hat must be used for a limited time only. Also, many will feel that using the hats is unnatural, uncomfortable or even counter productive 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.
Six distinct directions are identified and assigned a color. The sixth meta thinking (Blue) is discussed in the next section. The other 5 directions are:
Information (White) - considering purely what information is available, what are the facts?
Emotions (Red) - intuitive or instinctive gut reactions or statements of emotional feeling (but not any justification)
Discernment (Black) - logic applied to identifying reasons to be cautious and conservative
Optimistic response (Yellow) - logic applied to identifying benefits, seeking harmony
Creativity (Green) - statements of provocation and investigation, seeing where a thought goes