Common Sense Sucks

As HCI practitioners who believe in making technology slicker to use, our biggest opponents may be budgets, but coming up strong on the outside is stupidity based on common sense. Human psychology is a weird and wonderful thing, and I love studying it because there's always something unexpected waiting to mug you around the corner. Where others love bar fights, I love getting pasted by new knowledge. And research has shown for a long time that common sense is a lousy predictor of future events. You'd think that humans would be good at prediction by now, but we're not. For one thing, we think in linear terms - one cause, one effect. But the universe is gloriously nonlinear, and every event has many causes. Further, humans tend to predict based on what's going on now. When we ask "how would you like this?" or "how would you feel about this?", the respondent has to extrapolate based solely on how he feels at the moment. When we put this to the test, we find that the respondents don't really feel that way later on. This is why I put no faith in predictive surveys.

When those in power use common sense to make sweeping laws or spend huge sums of money, they too usually screw the pooch. The Freakonomics blog has a short piece on how abstinence-only sex education has actually resulted in more teen pregnancies, something any psychologist could have predicted. The urge to merge is far too strong to educate away, especially in adolescents who haven't yet developed much control over their impulses. The victims of abstinence-only education aren't given the tools to prevent disease or pregnancy, but they're driven to give in to the mating call anyway, resulting in more pregnancies. It's obvious from studies that abstinence-only ed doesn't work, and New York has appropriately dropped it, despite losing millions in federal funds. But the US Congress stubbornly sticks to the plan. Common sense is dooming teenagers and costing millions, all with no substantial foundation, but that doesn't matter.

The lesson for us is to mistrust common sense, both our own and our clients'. I've seen clients cling to old, unusable designs simply out of faith. Analytics, psychological principles, and user testing will eliminate most of the problems if they're used, but they won't be applied if common sense has anything to say about it.