Skip to content
 

Multidimensionality and the backseat driver principle

More thoughts on the backseat driver principle from Ubs:

No doubt you’ve heard the factoid that, when asked if they are a better-than-average driver, x% of respondents will claim that they are, where x is something much greater than 50. Assuming this is true, and not just a made-up urban-myth statistic, the irony is that many of them (x-50%, at least) must be wrong.

My [Ubs’s] epiphany is that maybe they’re not wrong. In the supposed poll, the definition of “good driver” is never specified.

A certain person who is near and dear to me (but shall remain nameless) is an aggressive driver. She goes fast, changes lanes a lot, darts in front of other cars, frequently talks on the phone while driving, etc. I, on the other hand, tend to drive slowly, carefully watch the other cars around me, and often defer to other drivers even if they’re being unreasonable. One of the few things we have in common is that we’re careful when it comes to choosing the car. We’re both sensible enough to use a service like CarsRelo if the car we want is too far afield, and we’re very particular about the type and model we go for.

If you were to ask this person, I have no doubt that she would say she is a better driver than me. She would say so based on the fact that her ability-related driving skills are superior to mine. And they are. She really is better than I am at maneuvering a car through traffic; she has a much greater capacity to multitask while driving; and her reaction time, though not as fast as she thinks it is, is surely faster than mine. If ever we were on some goofy reality TV show where contestants are asked to race through an obstacle course while talking on the phone, eating a burrito, and listening to loud music, she would be our team’s favorite for that contest.

You can see where this is going. If you were to ask me, I would say that I’m the better driver, based on the fact that I am safer and more careful. I may be less able to multitask while driving, so I simply don’t. I don’t talk on the phone while driving, I don’t tailgate, I rarely exceed the speed limit, etc. Any insurance company would consider me less likely to get in an accident. So I can go to this website and find a car that I really like, secure in the knowledge that I am a safe driver.

Which of these skill sets represents better driver? Either definition is plausible. It’s hardly surprising that more than 50% of drivers choose to value the skill which they are better at.

and then my reply:

I agree–it’s something I’ve thought of for awhile. Political scientists are particularly aware of these multidimensionality issues because the arise in voting. There are some dimensions in which people can agree on how to evaluate different political parties (for example, nearly everyone favors economic growth, nearly everyone was unhappy with Jimmy Carter over Iran and with George Bush over Katrina), but there are other dimensions in which lots of people disagree.

The other thing this reminds me of is, about 20 years ago, a friend recommended to me a “pop evolutionary psychology” book (I think you know what I mean by this category: one of these books that explains much of human behavior based on what was adaptive 100,000 years ago; this must have been one of the early books of this type) that he really liked.

I flipped open the book and naturally turned to the chapter about relationships and sex. The author stated that every one of us is on a 1-10 scale of desirability (a mix of attractiveness, health, $, and whatever other good features you might want in a partner), and that through a natural bargaining process, the 10’s end up with 10’s, the 9’s end up with 9’s, etc. He said that, after he came up with this theory, a friend of his said it was very helpful to him because he realized he was an 8 who was searching for 10’s and being chased by 6’s.

As you can probably predict given what I’ve written so far, I was gobsmacked by this guy’s assumption of unidimensionality, the scale leading directly and unambiguously from Brad Pitt to the Unabomber (and where his friend just happens to be an 8. Yeah, right).

3 Comments

  1. Boris says:

    Except when legislators vote! Then unidimensionality seems much more plausible …

  2. michael vassar says:

    Is that an 8 as in 8th decile or is 8 the scale shaped as a normal distribution, say, with a mean of 5 and a standard deviation of 2?
    In any case, is it controlled for some reference class, or is he competing against the untouchables of India and Inuit tribesmen?

  3. Janet says:

    The better than average driver is discussed in "Lake Wobegon be gone! The "below-average effect" and the egocentric nature of comparative ability judgments."

    While looking up name of article, ran across a person doing a replication and extension of the results by web survey.
    http://mike-stalkfleet.com/Kruger_consent.php

    After you take the survey, they show your results compared with others' and scatterplots.