Hierarchy of ideas
In inter-personal communication the person who controls the level of abstraction within the communication controls the communication itself.
The hierarchy of ideas is a model which assists us in our ability to move through and between different levels of abstraction from vague and ambiguous to concrete and specific.
The NLP Communication Model introduces the concept of information being divided into chunks of variable size and the idea that the conscious mind can usefully attend to 7+/-2 (seven plus or minus two) chunks of information at any one point in time.
The hierarchy of ideas also utilises this concept of chunks of information and our ability to take such a chunk and 'chunk up' to a higher level of abstraction, 'chunk down' to a lower level of abstraction and even 'chunk sideways' or laterally between two chunks at the same level of abstraction.
If we take the word car as an example, the word car is at a particular level of abstraction.
If we then chunk down on car we move to a lower level of abstraction - something more concrete and specific.
We can chunk down and gain specificity by asking 'What are examples of this?', or 'What specifically?'
So if the subject of the communication was car we might ask 'What type of car specifically?' and chunk down to Ford.
If we required further detail we could chunk down one more level by asking something like 'What model of Ford specifically?' and we might get a response of 'Mondeo' or 'Focus'.
In this particular example we've chunked down on the class or category of the subject in question. An alternative available to us to gain specificity is to chunk down on parts i.e. instead of chunking down from Car to manufacturer to model, we could also have chunked down from Car to engine to spark plug.
With each increasing level of specificity we are moving down through the hierarchy of ideas, down through levels of abstraction.