HCI research
should focus

of these are actually useful, but the original TomTom was the sweet spot.

David Liddle, design lead for the world’s first commercially available GUI computer, explains his theory of technology adoption in Bill Moggridge’s wonderful book, Designing Interfaces. He postulates a first, enthusiast phase exploiting the new technology, a second, professional phase putting it to use to get work done, and a third, consumer phase when it becomes available enough for people to enjoy.

I think we should add a fourth stage to this otherwise excellent model: the “baroque phase,” in which the successful new consumer product genre is then embellished with secondary features that often already existed before but are now integrated into the new product.

This phase obeys the terrible law of feature creep. Consumers, having experienced the wonderful new possibilities of the initial sweet-spot device, are hoping that subsequent products in this new genre will have an equally revolutionary and additional positive impact on their everyday lives—which of course they don’t, as they’re just incremental improvements—and so buy new models because of their added features. The resulting featuritis, prevalent in software, is spreading to consumer devices as they are increasingly software-controlled. (Shopping for a new toaster, I recently encountered a model that would assist me in my complex toasting tasks with an informational LCD screen. Please?)

At first sight the sweet spot

and the baroque phase seem hard to tell apart: Both give the user new features, just at different levels of originality. But there’s an easy test: Sweet-spot products make your life simpler, baroque ones more complex. Sweet-spot products support you in a new way, making a previously difficult or awkward task change fundamentally. Learn just a few new things, and you get an almost magical boost in productivity, simplifying your everyday life. Baroque products just tweak existing processes, trying to make them more efficient in some situations but often complicating other tasks (and sometimes the most frequent ones—think microwave ovens). And to use them, you often need to learn a fair amount of new interaction concepts, operations, and other lingo.

Let’s look at some products I consider worthy of a sweet-spot award, and some technologies way in their baroque phase.

Cell phones hit their sweet spot in the mid-’90s: pocketable handsets, with several days of standby and calling charges that didn’t ruin the average consumer anymore. What a change! Within years, people moved from carefully planning their evening out to “call us when you’re ready; we’ll tell you what bar we ended up in.” Agreeing when and where to meet, which often failed before, leading to heated arguments over whose fault it was (“But I was looking for you!”), was replaced by the stress-free model of just calling if something came up, no matter where everybody was. The list goes on.