Alistair Cockburn - Agile Software Development

Two of the participants complained about working with precise images: "You almost get committed to something before you know whether you like it or not" and "I have to decide beforehand what I want before I can draw it." (p. 200) One person said:

"One gets the feeling that all the work is being done internally with a different type of symbol system and recorded after the fact, presumably because the external symbol system cannot support such operations." (p. 200)

Pelle Ehn describes software design similarly. Recognizing that neither the users nor the designers could adequately identify, parse and name their experiences, he asked them to design by doing. In the article reproduced in Appendix B he writes: "The language-games played in design-by-doing can be viewed both from the point of view of the users and of the designers. This kind of design becomes a language-game in which the users learn about possibilities and constraints of new computer tools that may become part of their ordinary language-games. The designers become the teachers that teach the users how to participate in this particular language-game of design. However, to set up these kinds of language-games, the designers have to learn from the users. However, paradoxical as it sounds, users and designers do not have to understand each other fully in playing language-games of design-by-doing together. Participation in a language-game of design and the use of design artifacts can make constructive but different sense to users and designers."

That takes us pretty well to the boundary of ignorance: We don't notice what is in front of us, we don't have adequate names for what we do notice, and when we go to communicate we don't know exactly what it is we mean to communicate. The only thing that might be worse is if we couldn't actually communicate our message.

That little grimace

you just made across the dinner table

speaks volumes to me,

though it says nothing to the others around us.

You twisted your lips like that yesterday

to show how you felt about that fellow

who had behaved so awfully, when

you were trying to be nice.

I quite agree.

Actually, he rather reminds me of the man

on your left.

I raise my eyebrows a hair

and glance lightly in his direction.

From the stiffening of your top lip as you

continue to chew, it is clear you think so too.

Oh, oh. We've been spotted.

No matter.

Our conversation, although discovered,

will have no meaning to anyone else.

And the poor man on your left will always suffer

from the label we gave him

in this short conversation.

(Alistair Cockburn, 1986)

What is the information content of a raised eyebrow?

Don't look for the answer in Claude Shannon's seminal papers about information theory (Shannon 1963). He analyzed constrained channels, those in which the communication vocabulary is known in advance. In real-world communication, the channel is unconstrained. When or whether you raise your eyebrow is not prearranged. The "stiffening of your top lip" is the invention of a moment, referencing a shared experience with your conversation partner. In the poem above, the partner had that shared experience but the spotter did not. And so the spotter did not derive the same information content as the partner.

Biologists Maturana and Varela have investigated this in the context of biological system. The following wording from The Tree of Life, (Maturana 1998, p.196) describes their results:

"Our discussion has led us to conclude that, biologically, there is no 'transmitted information' in communication. Communication takes place each time there is behavioral coordination in a realm of structural coupling. This conclusion is surprising only if we insist on not questioning the latest metaphor for communication... [in which] communication is something generated at a certain point. It is carried by a conduit (or tube) and is delivered to the receiver at the other end. Hence, there is a something that is communicated, and what is communicated is an integral part of that which travels in the tube. Thus, we usually speak of the "information" contained in a picture, an object, or more evidently, the printed word.... According to our analysis, this metaphor is basically false. ... [e]ach person hears what he hears according to his own structural determination... The phenomenon of communication does not depend on what is transmitted, but on what happens to the person who receives it. And this is a very different matter from 'transmitting information.'"

To put it into words that are simpler, although perhaps less accurate biologically, each living being exists inside a membrane that transfers impinging events into internal signals, which initiate internal activities. It is really only the internal signals that the being "notices," not the external signals. The surprising thing is that the internal signals can also be generated by activities and events inside the being!

A being that "notices" something cannot be sure whether that something originated from an internal or external signal. Thus we "see" images in dreams and hallucinations, when the eyes are closed. Maturana and Varela studied this effect in color vision, finding that we regularly see a color in a scene that does not explicitly contain that color. We generate the color's presence through internal mechanisms.

The "behavioral coordination in a realm of structural coupling" is the correlation between those things impinging on the membrane from the outside and the internal activities that follow. Obviously, we wouldn't last very long as beings if there weren't a fairly good correlation between the outside events and the internal activities generated. It is important to recognize, however, that the internal activities are equally determined by the internal state of the being, its "own structural determination." The information received is not what impinges upon the receiver, but what happens inside the receiver afterwards.

To put this into a concrete example, consider that someone runs into the room and shouts "Fire!" in Japanese. A Japanese-speaking listener receives a lot of information, and immediately leaps up and runs to the exit. The Japanese person next to him, who happens to be asleep, receives no information at all. The external stimulus was never converted into an internal signal A person who speaks no Japanese notices that someone came in and shouted something but received no particular information from the sounds uttered. What each person receives from the shout depends on her internal condition.

Internal Restructuring

Information at the receiver's side is not a static, externally determinable quantity but rather a transient, dynamic personal quantity. The information received is a measure of the internal restructuring that follows the impingement of the signal. It is the quantity representing the size of the change in the receiver's predictive model of the world after receiving it.

Consider these few examples to see this in action:

"I am thinking of a set of numbers. The set includes 1, 3, 7, 11, 13,…”

At this point the listener has built up a predictive model that holds those numbers, the fact that they are in the set, and that 5 and 9 are conspicuously missing. They are conspicuously missing, because the typical person constructed a second model, "the odd numbers without 5 and 9," alongside the first.

The speaker continues with: "... 15 is in the set...”

On hearing this, the model grows by one element, that "15 is in the set." No new patterns show up.