Saturday, 19 May 2012

When is a user like a lemon?

Discussing the design lifecycle with one of my PhD students, I found myself referring back to Don Norman's book on emotional design – in particular, to the cover picture of a Philippe Starck lemon squeezer. The evaluation criteria for a lemon squeezer are, I would guess, that it can be used to squeeze lemons (for which it probably needs to be tested with some lemons), that it can be washed, that it will not corrode or break quickly, and that (in this case, at least) it looks beautiful.

These evaluation criteria can be addressed relatively rapidly during the design lifecycle. You don't need to suspend the design process for a significant length of time to go and find a representative sample of lemons on which to test a prototype squeezer. You don't need to plan a complex lemon-squeezing study with a carefully devised set of lemon-squeezing tasks. There's just one main task for the squeezer to perform, and the variability in lemons is mercifully low.

In contrast, most interactive computer systems support a plethora of tasks, and are intended for use by a wide variety of people, so requirements gathering and user testing have to be planned as separate activities in the design of interactive systems. Yet even in the 21st century, this doesn't seem to be fully recognised. As we found in a study a few years ago, agile software development processes don't typically build in time for substantive user engagement (other than by involving a few user representatives in the development team). And when you come to the standards and regulations for medical devices, they barely differentiate between latex gloves and glucometers or interactive devices in intensive care. Users of interactive systems are apparently regarded as being as uniform and controllable as lemons: define what they should do, and they will do it. In our dreams! (Or maybe our nightmares...)


  1. I remember seeing one of these lemon squeezers for the first time and having to ask someone what on earth it was ;)

  2. Ah, OK: so if you know it's a lemon squeezer and you want to squeeze lemons then it's probably usable (I've never tested it), but you've highlighted another important point: whether someone can recognise the function of the object, or whether it is treated as a work of art! I'm sure someone must have written about that...