One of my first jobs in user experience was designing an interactive voice response system for my company’s customer support line. it was more challenging that you might think… we had to understand the mental model of users who would call such a number, what their priority needs would be, how much “information” the caller can keep in his or her head at one time, etc. Such systems are still around, obviously, with some far better designed than others (I think the one I had a hand in was pretty good).
Now, however, we have an even greater challenge – how to design true voice interface systems, systems like Apple’s Siri that lets users do anything. I’ve been thinking a while about some “best practices” that can be applied to such interactions. Here’s my first swag at some good advice on how to make a good voice interface:
Be conversational. Respond in a way that is personal and polite, not monotonous or robotic. Just because it’s a computer doesn’t mean it needs to be a computerized voice. Be friendly, but…
Don’t get too personal. Avoid words or phrases that are overly critical or praising… It can come off as cloying and phony. While it was design in a different domain, I once evaluated an ATM UI that used phrases that were completely informal… It was off-putting and inappropriate.
Recover gracefully. When mistakes are made, learn from them. Apologize, and remember. Design a learning system. Yes,I know, this is easier said than done, but it’s important.
Respond quickly. Latency is DEATH to a voice control system, because the user is expecting the response immediately. Every time the system responds with “thinking” is a moment where the user’s confidence is reduced.
Be ready for ANYTHING. Build out “trees” that account for as many eventualities as you can think of. Be thorough. Defaulting to a web search is not a positive outcome. In creating a voice interface system you should aim for a complete solution, and deliver it… and users will use the system with great confidence
Be reliable. A voice response system that doesn’t respond… well, that’s not a very good thing, is it? Make sure that the system is like the dial tone should be when you pick up the phone – always on, always ready.
Provide alternate inputs, but use voice first. One of the things that Siri does badly is when users has to confirm something. Most of the time the user has to click a “yes” or “OK” button. Why? You’re already talking to the device, the device should KEEP LISTENING.
Avoid doing HAL 9000 jokes. I know it’s tempting, but it’s played out. But do pay attention to how movies like Moon, 2001, and Star Trek presents voice control systems, because that is the “training” that all of us have had. Understanding the expectations that users have of these systems can help you design them better.
Get out of the way whenever possible. Interacting with a voice system is cool now, but in the future it will become as normal as driving a car or watching TV. Once the novelty wears off, people will be more results and outcome-focused… so don’t be cute. Provide an interactive experience that obeys commands and gets out of the way, with no editorial comments.
In closing, I have always said that we are living in the future, it just wasn’t the future we were expecting. The very fact that I can write this type of article as a serious piece of guidance to designers instead of a blue-sky puff piece… well, that just proves my earlier point. The future has arrived.