Aiming for the center

11.04.2011 21:08

Software that exposes its user interface over the web offers limitless opportunities for monitoring the behavior of people using it. You can literally watch each move of the mouse and each key press. And it's so tempting to gather all this information and try to make sense out of it that some are pushing this idea of data centered design where each decision must come from a bump in a graph or two. From my point of view as an engineer (UX is not in my verbal vocabulary) I find that kind of approach shortsighted at best.

You are invariably optimizing for an average user, even if you divide people into neat little numbered bins. Consider an analogy from the physical world: Center of gravity is the mean location of mass in an object. In many objects, like in this ring for instance, it is also devoid of any mass. Optimizing something for the average user can mean you simply make no one happy and everyone equally miserable.

Ring with a center of gravity mark

AB testing and similar ideas are just hill-climbing optimization algorithms for some variable that ultimately depends on processes in a wet human brain. Such simple approaches fall short in the real world where laws of physics are infinitely less complex. How can they be the main guide for development in user interface design, where a linear law is replaced by chaotic mess of firing neurons? I don't doubt that in some time in the future well be able to understand and model it (and that certainly won't be a two dimensional graph with vaguely defined axes). Until then it will take a human to understand a human.

Some may argue that at large scales groups of people are surprisingly predictable. My answer is that it's also well known that entropy increases in the universe. That doesn't bring you any closer to designing an internal combustion engine.

I'll stop myself here and won't go into the impossibility of doing controlled experiments with people or the moral problem I see in choosing profit as the universal optimization variable for all design questions. I'll offend enough liberal arts students as it is.

Measurements are important in evaluation, but anything involving a human in the loop is one significant figure at best. Modifying things based on that second decimal increase in metric instead of going with the gut feeling of what is best just takes everyone a little further from happiness.

Even if you reap mad profits from that bouncing blinking purchase button.

Posted by Tomaž | Categories: Ideas


I didn't know you're a creationist ;)

Posted by Dušan

Now that you mentioned it, evolutionary algorithms are much better suited for solving complex problems than simple hill climbing. Though their requirement for a huge number of experiments makes them unusable in the web environment that can hardly manage a single one.

To follow your metaphor, design and evolution both work on a completely different level than simple searching for local minima.

Posted by Tomaž

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