The Frontal Cortex

Bumper Stickers Are Dangerous

When I first got a Prius, I was tempted to cover the rear bumper with liberal decals, like “Support Local Farms!” (that’s on my bike) or “Women for Obama!” (a popular Prius sticker here in New Hampshire). I wanted to embrace my inner cliche, to see what it felt like to be a right-wing talking point. (I also enjoy the occasional latte…) But then, just as I was about the deface the car with ideological mottos, my better half intervened. She had no interest in being a cliche.

As usual, my better half was right: it turns out that putting bumper stickers on your car increases your aggressive tendencies as a driver. When you cover the vehicle with marks of identity, you become more sensitive to “invasions of territory,” which apparently include being cut off by another car:

Watch out for cars with bumper stickers.

That’s the surprising conclusion of a recent study by Colorado State University social psychologist William Szlemko. Drivers of cars with bumper stickers, window decals, personalized license plates and other “territorial markers” not only get mad when someone cuts in their lane or is slow to respond to a changed traffic light, but they are far more likely than those who do not personalize their cars to use their vehicles to express rage — by honking, tailgating and other aggressive behavior.

It does not seem to matter whether the messages on the stickers are about peace and love — “Visualize World Peace,” “My Kid Is an Honor Student” — or angry and in your face — “Don’t Mess With Texas,” “My Kid Beat Up Your Honor Student.”

Drivers who do not personalize their cars get angry, too, Szlemko and his colleagues concluded in a paper they recently published in the Journal of Applied Social Psychology, but they don’t act out their anger. They fume, mentally call the other driver a jerk, and move on.

“The more markers a car has, the more aggressively the person tends to drive when provoked,” Szlemko said. “Just the presence of territory markers predicts the tendency to be an aggressive driver.”


  1. #1 Brian Schmidt
    June 16, 2008

    The question is whether aggressive types are more likely to add stickers, so the causation effect runs a different direction.

    For my part I view my three stickers as advertisements and try to temper my aggressive driving, since that driving doesn’t help my advertising.

    One of the stickers I made for myself for my Prius – it says “Al Qaeda Hates This Car”.

  2. #2 Felstatsu
    June 16, 2008

    Interesting, it’s totally believable, but the only person I know with stickers and whatnot on the back of their car is one of the mellowest drivers I know. Then again we are all a little bit odd in the group of people I hang out with so it could just be that we’re naturally outliers in all the studies we participate in (I know I am more often than not). Back to the driver though, she does mostly have the love and peace stickers, but they really are there more because she believes in having love and peace than because she thinks they look good or are part of some fad so if anything, knowing those stickers are on the back of her car might help her drive less aggressively and keep her from getting as angry when someone else cuts her off or does something else that’s under the bad driving category.

  3. #3 oku
    June 16, 2008

    Funny. Just when I thought about buying this sticker for my Prius.

  4. #4 speedwell
    June 16, 2008

    Or it could just be that people put bumper stickers on their cars are just likelier to be the expressive type than people who don’t? Why blame it on bumper stickers?

  5. #5 greg
    June 16, 2008

    I don’t have any stickers. I think the more aggressive drivers who have stickers would most often have the redneck right-wing variety.
    I think I have seen more right-wing stickers than anything else.

  6. #6 NJ
    June 16, 2008

    Hmmmmm. Don’t think it would apply. I had a sticker on mine that read: On the advice of counsel, this bumper has no comment

  7. #7 unicow
    June 16, 2008

    I think I’ll make myself a bumper sticker that reads “Correlation Does Not Equal Causation” just in case any of these researchers come to my town.

  8. #8 Road Meekness
    June 16, 2008

    Hmmmm. Considering my sister claims that I wait for a written invitation before I dare to move into traffic, maybe I should put MORE bumper stickers on my car, so I reduce the road rage of those behind me.

    An increase in aggression may not be all bad. It all depends on where you start on the scale.

  9. #9 John Benbow
    June 16, 2008

    Once saw a car with a sticker: Honk If You Love Jesus!
    I honked and got a single-digit hand signal and the greeting “Asshole!” in response.

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