The Element of Surprise

Surprise is not a word that user interface designers typically like to hear. Indeed, the principle of least surprise (also called the principle of least astonishment) is that systems should always strive to act in a way that least surprises the user.

Like many interface design principles, the principle of least surprise reflects the premise that software applications exist to be useful. In utility-oriented applications, surprise means distraction and delay — negatives that good designers work to avoid.

But we increasingly see applications whose main value to the user is not utility, but entertainment. Indeed, a recent Nielsen report claims that the top two online activities for Americans are social networks / blogs and games. I take the report with a grain of salt, but it seems safe to argue that people have come to expect the internet to be at least as fun as it is useful.

Even search, which would seem to be the poster child for the utility of online services, is being pressed into the service of entertainment. Max Wilson and David Elsweiler argued as much in their HCIR 2010 presentation about “casual leisure searching“. They mined Twitter to analyze a variety of scenarios where search isn’t about the use finding something, but rather about enjoying the experience. Indeed, their controversial definition of search is broad enough to include the possibility that the user does not have an information need.

Like the businessman in Antoine de St. Exupery’s Le Petit Prince, I’ve long felt that, as “un homme sérieux”, my job is delivering utility to users. Users already have lots of ways to waste time; I focus on making their productivity-oriented time more effective and efficient. I’m glad there are folks who devote their lives to making the rest of us have more fun (especially all the computer scientists who left academia for Pixar), but entertainment simply isn’t a vocation for me.

However, I’ve been coming around to the realization that fun and utility are not mutually exclusive. For example, news serves the utilitarian ideal of informing the citizenry, but many (most?) of us read news as a pleasant way to pass the time. Social networks are another example serving a similar function–perhaps with a balance that is more toward the entertainment of the spectrum but still providing genuine social utility.

A common feature of both of these examples is that users regularly return to the same site expecting the unexpected. The transient nature of news and social news feeds promises an endless supply of fresh content, produced more quickly than users can consume it. This situation is in stark contrast to those of typical web search queries, for which the results are expected to be largely static. Indeed, we may set up alerts to inform us of novel search results, but we are unlikely to regularly visit a bookmarked search results page the way we regularly visit a news or social network site.

Is novelty the only source of surprise? Novelty certainly helps, but it is not a necessity. An alternative source is randomness. I’m known people to use Wikipedia’s “random article” feature. But a more plausible place to introduce randomness is in recommendations — whether for products or content. Since recommendations are good guesses at best, a bit of randomness can help ensure that the guesses are interesting. Indeed, a SIGIR 2010 paper by Neal Lathia, Stephen Hailes, Licia Capra, and Xavier Amatriain on “Temporal Diversity in Recommender Systems” explored the use or randomness to induce diversity in recommendations and arrived at the conclusion that people don’t like being recommended the same things over and over again.

Can we generalize from these examples? I think so. For utility-oriented information needs, it is important to provide users with accurate, predictable, and efficient tools. But we can’t dismiss everything else as frivolous. Sometimes we just need to offer our users a little bit of surprise to keep it interesting.

Or, as Mary Poppins tells us: “In every job that must be done, there is an element of fun. You find the fun, and – SNAP – the job’s a game!”