More interesting is the case of what Pask calls “I/you-referenced” interaction: Not only does the second system take in the output of the first, but the first also takes in the output of the second. Each has the choice to respond to the other. Significantly, here the input relationships are not strict “controls.” This type of interaction is a like a peer-to-peer conversation in which each system signals the other, perhaps asking questions or making commands (in hope, but without certainty, of response), but there is room for choice on the respondent’s part. Furthermore, the systems learn from each other, not just by discovering which actions can maintain their goals under specific circumstances (as with a standalone second-order system) but by exchanging information of common interest. They may coordinate goals and actions. We might even say they are capable of design—of agreeing on goals and means of achieving them. This type of interaction is conversing (or conversation). It builds on understanding to reach agreement and take action [ 15].

There are still more cases. Two are especially interesting and perhaps not covered in the list above, though Boulding surely implies them:

• learning systems organized into teams

• networks of learning systems organized into communities or markets

often described as basic interactions. Yet reacting to input is not the same as learning, conversing, collaborating, or designing. Even feedback loops, the basis for most models of interaction, may result in rigid and limited forms of interaction.

By looking beyond common notions of interactions for a more rigorous definition, we increase the possibilities open to design. And by replacing simple feedback with conversation as our primary model of interaction, we may open the world to new, richer forms of computing.

ABOUT THE AUTHORS Hugh Dubberly manages a consultancy focused on making services and software easier to use through interaction design and information design. As vice president he was responsible for design and production of Netscape’s Web services. For 10 years he was at

Apple, where he managed graphic design and corporate identity and co-created the Knowledge Navigator series of videos. Dubberly also founded an interactive media department at Art Center and has taught at San Jose State, IIT/ID, and Stanford.

Paul Pangaro is the CTO at CyberneticLifestyles.
com in New York City, where he consults at the
intersection of product strategy, marketing, and
organizational dynamics. He is recognized as an
authority on search and related conversational
impedances in human-machine interaction, and on
entailment meshes, a highly rigorous framework for representing
knowledge. He was C TO of several startups, including Idealab’s
Snap.com, and was senior director and distinguished market strat-
egist at Sun Microsystems. Paul has taught at Stanford University.

[ 15] Pangaro, P.
“Participative Systems.”
November 2000.
< http://www.pangaro.
com/PS/PS2005-v1b-
4up.pdf>

The coordination of goals and actions across groups of people is politics. It may also have parallels in biological systems. As we learn more about both political and biological systems, we may be able to apply that knowledge to designing interaction with software and computers.

Having outlined the types of systems and the ways they may interact, we see how varied interaction can be:

• reacting to another system

• regulating a simple process

• learning how actions affect the environment

• balancing competing systems

• managing automatic systems

• entertaining (maintaining the engagement of a learning system)

• conversing

Usman Haque has created responsive environments, interactive installations, digital interface devices, and mass-participation performances. His skills include the design of both physical spaces and the software and systems that bring them to life. He has been an invited researcher at the

Interaction Design Institute in Ivrea, Italy, artist-in-residence at Japan’s International Academy of Media Arts and Sciences. Usman has worked in the U.S., U.K., and Malaysia. As well as directing the work of Haque Design + Research, he was, until 2005, a teacher in the Interactive Architecture Workshop at the Bartlett School of Architecture.

January + February 2009

We may also see that common notions of interaction, those we use every day in describing user experience and design activities, may be inadequate. Pressing a button or turning a lever are

DOI: 10.1145/1456202.1456220
© 2009 ACM 1072-5220/09/0100 $5.00