People have asked me, in light of John Maeda’s new book and blog, I suppose, why simplicity isn’t one of the characteristics of good interaction design I list in my book. (The characteristics are trustworthy, smart, clever, appropriate, responsive, ludic, and pleasurable.)

The reason is pretty, well, simple really: I don’t think every good interaction design needs to be simple. Certainly, many good designs are. But many aren’t, and I don’t think you’d necessarily want them to be. I don’t want my games to be too simple, for instance. Nor would I want it to be too simple to, say, launch a nuclear strike from a control center. I tried to chose characteristics that held true in most circumstances.

Users don’t always want the advanced features stripped away from them, and sometimes prefer having more complexity because more complexity can sometimes provide users with more control. Simplicity puts a lot of control in the hands of the designer. We say, you only get these features and users have to deal with that. Sometimes, this is great: we’ve hidden a lot of complexity. But sometimes, we de-skill users by only giving them the lowest common denominator. No advanced features for you! It has to be simple! It’s a fine line to walk.

My take on it is roughly Einstein’s: “As simple as possible, but no simpler.”