Exformation is a term related to information for describing useful and relevant information or a specific kind of information explosion. With exformation, thought is in fact a process of throwing away information, and it is this detritus that is crucially involved in automatic behaviours of expertise such as riding a bicycle or playing the piano.
In using words, sounds and gestures, a speaker has deliberately thrown away a huge body of information, though it remains implied. Exformation is everything we do not actually say but have in our heads when, or before, we say anything at all. Information is the measurable, demonstrable utterance we actually come out with.
If someone is talking about cows, what is said will be unintelligible unless the person listening has some prior idea what a cow is, what it is good for, and in what context one might encounter one. From the information content of a message alone, there is no way of measuring how much exformation it contains.
In 1862 the author Victor Hugo wrote to his publisher asking how his most recent book, Les Misérables, was doing. Hugo wrote “?” in his message, to which his publisher replied “!”, to indicate it was selling well. This exchange of messages would have no meaning to a third party because the shared context is unique to those taking part in it. The amount of information was extremely small, and yet because of exformation a great deal of meaning was clearly conveyed.