Principles of ITV Interaction Design

Early in the design of the Zoetrope interactive television applications, I collected these seven principles of interactive television (ITV) interaction design. I posted them on my wall, and referred co-workers to them regularly. Making the principles public and visible helped maintain consistency and reduce controversy through discussions with engineers, designers and clients on both sides of the Pacific Ocean. User tests showed that the resulting design was quite successful for consumers as well.

Some of these principles come from basic interaction design theory, and some are more specific to users who are sitting on a couch across the room from the television screen. While there are many possibly relevant design principles, I developed this list because these principles addressed consistent problems from the project, and because a short list was easy for others to remember and champion.

Approach:

Interaction with a television is fundamentally different than interaction with a PC. Many designers have created complicated, input-intensive applications for the television. Television watchers are looking to relax, to be entertained. A television is watched in a "lean back" atmosphere, as opposed to the "lean forward" attitude of most personal computer users. Also, using the remote control as an input device means that the input is always in discrete keypresses, and the output must take this into account.

Principles:

• Give immediate visual and audio feedback to the user for every action.

• Maintain a clear focus. The user should always be able to answer the question "Where am I now?" on any screen with a glance.

• Distinguish selectable items from the rest of the screen. The user should be able to easily answer the question, "What can I do now?"

• Always respond to the main "select" button. This is the most common type of input, and the user is likely to use it as a default.

• Eliminate the need for an "error" tone. If an action is the wrong thing to do, the user shouldn't have the option to perform it.

• Make all choices accessible with the primary navigation controls (in this case, the 4 arrow keys & the "select" button). This does not preclude the use of secondary controls or expert shortcuts, but for every choice, including "return/go back to the previous screen", there must also be on-screen navigable access.