Design as Abstraction

I am going to posit that good design means coming up with good abstractions.

What do I mean by abstractions?
Anything that takes you up a level of abstraction so you don’t have to worry about the underlying details anymore. For example, WYSIWYG interfaces abstract away the fact that the computer is really manipulating some sort of data store. Data stores themselves abstract away the details of memory mangagement and disk access. Physical inventions like glue and paint abstract away from the chemical underpinnings; electrical tools abstract from their electrical basis. Rice cookers abstract away from the details of stove temperature and cooking time.

What makes a good abstraction?

  1. Good abstractions are powerful, in the sense that they let you do a lot with the very same tool. This is what Will (the designer of many of the Sim games) said.
  2. And good abstractions are not “leaky” – they do not force the user to resort to, or even understand, the underlying details that the abstraction is supposed to cover up. This is what Joel (On Software) said.
  3. Good abstractions are conceptually understandable, so that users can actually figure them out. Don Norman talks about the connection between devices and users’ mental models in “Design of Everyday Things”.
  4. And good abstractions are reliable, in that they extend to all relevant circumstances. This reliability develops users’ trust and satisfaction – which is discussed in Norman’s “Emotional Design”. It also enhances the power of the abstraction.

Computer monitors are very powerful — they can display essentially infinite patterns via a simple abstraction of colored pixels. They successfully hide the underlying digitical circuitry. They are trivial to understand. And well-manufactured, they are reliable for years (and each pixel supports a relevant range of brightness and hue). I think these factors explain the computer monitor’s enormous success as a design.

Artificial Intelligence approaches often try to take great leaps of abstraction. Instead of typing letters, you say a word and expect the computer to understand which letters you meant. Snap a photo and expect the computer to recognize your friend. Such approaches will only be widely successful when they are sufficiently powerful and leak-free. Shouldn’t they work all the time, even in low-light situations? Shouldn’t they recognize all your friends, not just some? How about people you’ve never met? The recognition abstraction implies that these are all relevant circumstances, so it is hard to develop the user’s trust without supporting them all. User understanding about which of these circumstances are too technically challenging requires breaking the abstraction (leakiness). All of this suggests that these approaches will not be successful unless the limitations are clearly and easily understood (as in limited domains like speaking digits) or the technology eventually manages to fulfill all the expectations of the abstraction.

Outside of limited domains, I think the “pure recognition” abstraction is doomed because of the real ambiguities that exist in the world. There is often absolutely no way to tell the difference between certain words that sound the same or faces that look the same. The only way to know for sure is to ask questions, look at context, keep gathering data until the ambiguity is resolved. Since the user is involved in providing context, gathering more data, and answering questions, this requires a different metaphor – a “conversational recognition” abstraction. The CEO of ConceptQ was talking about this, and exploratory search interfaces like faceted browsing function along the same lines.

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