Monday, August 22, 2005


convergence and requisite variety

What do you do when a video call interrupts your viewing of a streaming news clip that you are watching on your mobile phone? I faced this situation recently while trying out a 3G handset. I learned that the connection for the news clip stream got broken.

As network operators and handset makers cram more functionality into a device, users face a new kind of challenge. While device complexification is almost an iron-clad law of electronics, recent developments in mobile devices up the stakes. Unlike with standalone devices, mobile users don't have the option to ignore the stuff they don't understand how to use. Network connectivity forces users to deal with interruptions from others who want to communicate in an increasing range of ways.

Multifunctional mobile devices, and embedded pervasive computing, point to a world where users will have interaction foist upon them, ready or not. The "law of requisite variety" suggested by cybernetic theorist Ross Ashby in the early 1950s is highly relevant. The law states that users need at least as many kinds of controllers available to them as variety of situtations they need to control. For some reason requisite variety has received scant attention in usability and HCI literature. One reason may be that traditional HCI has viewed the user as initiating interaction with a machine, rather than having situations thrust on him or her.

One of the earliest thinkers on the topic of convergence was the late NEC chairman Koji Kobayashi. Twenty years ago he wrote a book called Computers and Communications where he argued users would someday use phones tell computers to act on their behalf, doing smart work like translating conversations in real time. Kobayashi's answer to requisite variety was to hide it from users and have computers deal with the complexity presented by convergence.

Kobayashi penned his vision during the expansive 1980s, when Japan was funding 5th generation computing research aimed at creating rational AI machines. We are still far from realizing that vision.

For now, the chore of managing the complexity associated with convergence falls on the user. Requisite variety tells us there is no escaping the need to give the user ways to manage the complexity. Previously, rich functionality was something power users discovered, and mainstream users ignored. Now, power users, when contacting mainstream users, will force the mainstream to confront functionality they may have had no intrinsic interest in discovering. The need for good usability has never been greater.

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