A broad definition is too inclusive.
A narrow definition is too exclusive.

How will defining "interactive"/"interactivity" help us?

We operate daily with "vague" definitions. I would argue that most of our definition are vague. There is an entire philosophical study of vagueness. And I will post it as soon as I can find it...

But for now I am fond of this broad and vague definition:

A "text" is interactive if it provides an interface to accept input that alters either the sensory experience in reaction to the "user" or the form/structure of text itself.

This is subject to elaboration, revision and debate.
I encourage discourse.

KMAC

Interactivity can be defined in myriad ways - the key is the consistency in this definition in either discourse or production. Kinder would define interactivity as a cognitive practice, and therefore for her, the works of Buñuel, Bergman, and others are interactive because of the way she has defined it - these films force us to cognitively piece together a narrative from +/- discreet parts. I would tend to disagree, because my definition of interactivity would probably tend more toward's kurt's - although I would question the inclusion of "interface," unless that term is defined in a like manner. Think about Robeky's VNS - is this an interface, or is it something more transparent? I would tend towards the argument that the interface becomes invisible (this would depend on how your program worked). It all depends on how you define interface. For example, I would tend to think of traditional musical instruments as not having an interface because they a) involve an element of mastery and b) are mutable in use. I'm confident that kurt would find musical instruments to be an interface. My point is that definitions exist so that we can make progress - move somewhere, not so much so that we can argue infinitely about this defintion or that definition. I think this idea is important, especially when we are discussing new technologies / mediums that haven't had a chance to fully develop.

I too have an opinion about this and spent several of mamber's class trying to organize a definition. sadly, my notebook is at home and im at work, so that comment will have to wait.

will said:
For example, I would tend to think of traditional musical instruments as not having an interface because they a) involve an element of mastery and b) are mutable in use.

they most certainly have an interface. you interact with the instrument and the manner in which that is organized and allowed defines that. based on your definition, windows xp does not have an interface (no comments on the actual os please). windows involves an element of mastery (quick, whats the keyboard shortcut for select all?) and is mutable (i have about a dozen different skins for xp on my computer currently).

how do either of those standards define a ui?

check out 'design of everyday things' for more about ui's of common things (phones, radios, etc).

First of all - don't confuse the GUI of the modern OS with UI - you have to think of the essential functional qualities of everyday things (yes, I've read most of the book). So in that case, I'd tend to disagree that all objects have interfaces, because I guess my defintion of interface is different than the one that they use. I think it's a question of if the fundamental function of an object supercedes the way in which the object was designed. The argument could certainly be made that those two things are not discrete. For example, in order for a guitar or other stringed instrument to resonate and produce varying frequencies, I think that the laws of physics are the dominant influences on design.

But now we are in an argument about authorship - the design of a UI subjecting a user. I guess that's actually a prerequisite for what an interface is by my defintion. So with these designs, I would agree that even if I master something, I'm still just playing the cards someone else dealt me.

Ok. But by limiting ourselves to just this argument: "everything has an interface," you are fundamentally ignoring the abillty of people to subvert interfaces. I agree that with the major OS's, subverting the interfaces designed by people in Cupertino or Redmond is difficult. However, it is quite easy to subvert the interfaces on other devices - especially musical instruments. So when this subversion occurs, all of the sudden the role of authorship has changed. Don't think that just because an interface is designed by someone, that consumers/users have no agency. And then the question remains - when people refashion, keeping with the musical instument line, a piano, are they just creating a new interface, but this time just one that THEY designed? Hmm. Now that's a good question...

The VNS has an interface: the camera system. The cameras accept input from the user, which in this case is a wide range of expressive body movement.

And the VNS is interactive according to my definition by satisfying the first disjunct:

it provides an interface to accept input that alters either the sensory experience *generated* in reaction to the "user".

While the form/structure of the "text" (the physical VNS system is not altered in performance) itself doesn't change, the visuals produced are dependent on the user's input.

Will:

I think your questions of interface authorship are interesting, but probably for a different reason than you do. If it serves the purpose of understanding interactivity better than I think a tangent to define "interface" is a worthy challenge.

I do think that every "thing" has an interface (probably not just physical things but ephemeral/conceptual ones as well...) whether or not that interface is artificially designed (created by humans). An apple, a natural object (please suspend any discourse on creation/evolution theories that might make it "designed"), has an interface to all five human senses (also suspend discourse on any purported sixth sense). I believe that sight, touch, taste and smell are clear. The sound interface of an apple is perhaps the satisfying crunch associated with the first bite through the skin. So the apple "interfaces" with each sense sometimes simultaneously and sometimes independently. Maybe I can propose a temporary definition of interface then:

An interface is the point of relationship between two objects (as loosely defined as possible) such that a transfer of physical phenomenon (in order to include non-matter) or information is made possible, in either direction or both directions.

This is a very inclusive definition. And may allow for some things to have interfaces that we intuitively believe do not. But it does have the benefit of boiling down to a primitive state what an interface is: a point of physical, informational or sensory contact which allows for an exchange. The exchange is the key. Suppose two surfaces of solid object were "touching" but nary an atom was disturbed by that contact. This would not be an interface. Besides not satisfying the definition I have provided, I think intuition tells us that it is not an interface.

So who is the "author" of the interface?

1) The author is the person that "designs" the method of exchange. If a person chooses to play the guitar with his/her feet (it can be done, I have been to a concert of an armless guitarist) then that person has authored a new interface.

Doesn't seem right. We intuitively understand the interface of a guitar to be "within" the guitar itself. Just as the interface of a radio to be contained by the control panel that was designed for it. Although the radio's "interface" (the control panel) may be removed and replaced with another interface. But I think it is clear that in such a case the radio with a new interface would be a different radio from the first (even though they share the same internal components).

I accept your conception of "interface," but I think things get tricky when you begin to translate that into a user interface. Defining interface that broadly is easy - there is no direct motive to design other than evolution/nature, no author other than nature. Sure we understand the interface of the guitar to be "within" itself, but the user interface of the guitar can be subverted. What is the user interface of the VNS for someone randomly walking through an installation equipped with the system if they cannot see the camera? The interface would be space, probably, as they would react to their own movement through it - but what is the user interface?

In other words, perhaps I don't think it's that useful, at least for me, talking about the interface in the way that kurt is, although I am in agreement with him. To me, this is too general, and cannot really raise any new or productive issues - this goes back to a seemingly endless discussion that kurt, tripp and I have been having about "the arbitrary."

I guess I've been taking about USER interface (I should have clarified) - how does the UI influence interactivity? I think this question brings up a number of issues about authorship that are perhaps more ideological in nature, but that also push us beyond basic ways of understanding interactivity. The armless guitarist, or even the MIDI violinist is subverting the user interface of those instruments - but are they designing new USER interfaces? Certainly they are redefining as kurt would say: "the method of exchange," but are they establishing a new rule set by which they can conjure this "exhange." For the purpose of this dialogue, I would tenatively define the USER interface as a system of rules within which a user establishes this process of exhange. The author of a user interface sets these rules.

I'm getting a little verklempt! Talk amongst yourselves...

...I'll give you a topic, discuss whether a user interface is neither a user nor an interface...discuss!!!

Okay, but seriously folks, back to the question/definition of interactivity. I would have to say this;
Interactivity is the exchange of user input into a system for output that directly affects the user(s).

In this way, I feel that Kinder's definition works but from a very different perspective. The interactivity is happening on the user's behalf, it is solely that of the individuals perceptions. We walk into a Bunuel flick, watch it, receive input, process, produce output and judge our respones to the film. Notice that I said the film gives US input. We have no input into the film. It is therefore cunstructing a form of interactivity amoungst ourselves...hehehe...where by we are the system, the process and the producer of output, not the film. I beleive that the film is the "mode" or "vehicle" to receive the information, so to speak.

In a sense, interactivity is present with an inside out perspective when dealing with Kinder's approach. I feel that the system we "interact" with (my interactivity definition) is a tangible one (maybe digital) that receives the input, processes, then produces output. A person picks up a Viola, tunes it, plays it, gives it input, the instrument resonates, produces a mode of output that can affect the user or users. The author of the viola (the creator of the instrument) only changes that process BEFORE it begins, therefore it doesn't affect the system in immediate terms. The author may be able to build the body smaller, call it a violin, and then have it go through the "system" described above. Much like a film, it is created, then put through the "system", regardless of the audiences cognitive thought processes.

I would really like to see a different name created for Kinder's definition of interactivity. Or maybe ours. Or both. Inside out interactivity would include things like tangible media interfaces, video games, and the like, somthing we touch, play with, push, pull shove, shout, breathe or sneeze on. Outside in would be like Bill Viola's Passions, some of Hisham's video work (not the cave stuff) and Kinders old French films.

I am sure this argument is full of holes, please feel free to exploit them so I may be able to strengthen my position.