If you would like to ponder on how prejudices, stereotypes and bias worm their way into our brains, look no further than here, a Yahoo! report, via the Wall Street Journal, about how research backs up the widespread belief that drivers of BMWs are jerks. (Full disclosure: my son drives an old BMW, and loves it dearly. I love it less, because repairing the damn thing has required me to moonlight by entertaining at kids’ birthday parties and rodeos…)

Various studies, we are told, show drivers of the car are less likely to yield to pedestrians in crosswalks and to take the upper hand at four-way stops. In addition,

“…in the U.K., motorists were asked to identify the make and color of the car from which they have most frequently suffered road-rage incidents…The study of 2,837 motorists found men between the ages of 35 and 50 driving blue BMWs were most likely to be reported as having engaged in road-rage behaviors such as aggressive driving and swearing.”

Well, that proves it, right? A few more such studies, and we’ll all know to watch that blue BMW on the highway extra-closely, because the driver—this is science talking, now—it’s a nut case, ready to cut me off or go postal if I don’t defer to him at every turn. Naturally, confirmation bias has also been triggered, so everything this car does will instantly be interpreted in the worst possible light. And when I’m looking back on the various irritating incidents in my vehicular travels, sure the ones involving BMWs stick in my mind. Maybe even when they weren’t really involved.

Then, when I go to a dinner party and learn that a new acquaintance owns a Beemer, I begin with the presumption that he’s a jerk, because, well, you know his kind, and besides, look at the statistics! That night, every joke, every bit of body language, everything I learn about him will seem like an embodiment of his residence in the jerkdom. Just look at him double-dipping the baba ganoush!

Wouldn’t it make sense for police to selectively stop BMWs, especially blue ones, to check for expired inspection stickers and proof of intoxication? If we know they are driven by jerks, or the majority of them, anyway, shouldn’t we presume the drivers are somehow being jerkish, or maybe about to be jerkish, and stop as many of them as we can before they hurt someone?

We reason this way about dozens of varieties of people and things, based on experience, lore, history, observation, statistics, and “studies.” It seems logical in the abstract, which is why it embeds itself as a bias. The problem, and the reason why acting on such reasoning is unethical, is that individuals aren’t abstractions, and treating them as abstractions is inherently unjust.

We can tell ourselves that. Living that way is much, much harder.