Prejudice and Bias

Only stupid people judge once.

For the rest of us, the world is a pretty exciting place. There’s always new things to consider, surprising details come up, and the “sure thing” of yesterday becomes the “maybe!” of today (and vice versa!)

At any given time, what we think of a person, a situation, or an event is our judgment. What we thought about it the last time (and the time before that) was our prejudgement, or prejudice. Our prejudices form our bias. What we will think in the future is our Monday morning quarterbacking, the difference between which and what your judgment is our hindsight bias.

If you have the correct prejudices, your hindsight bias will be l0w because your judgment will be correct. The Zimmerman Affair provides a good example of how this could work.

Knowing nothing else about the case, reasonable prejudices would provide a pretty good clue as to who violently attacked whom in the following pair.

person 1:
Sex: Male
Age: Upper 20s
Height: 5’7
Workplace: Desk
Fitness: Out out shape
Ethnicity: Hispanic

person 2:
Sex: Male
Age: Upper teens
Height: 5’11
Workplace: Unemployed (full time school)
Fitness: Athletic
Ethnicity: African-American

With this prejudice, all facts are filtered (this is analogous to the Bayesian process of “updating priors“) and one would come to the same conclusion that the jury in the Zimmerman case did: person 1 is not guilty on all counts.

But of course, only stupid people judge once.

Time goes on, our priors of person 1 are continuously updated , though there is a censorship effect in gathering new information about person 2.

There are remarkably easy ways to predict when some people have the wrong biases. But that is a post for a different time.

5 thoughts on “Prejudice and Bias”

  1. Hey Steve,

    You’re exactly right there are other factors related to mass. Weight, build, fat/muscle ratio, fights previously won, fights previously won in the last year, etc.

    The table in the example contains only attributes that are clear in their interpretation, either in context of the dyad or at least against the general population. I really have no idea how fat mass impacts likelihood to be in a fight.

  2. I read this post and remembered that in pretty much every bar fight I’ve ever seen I have never seen a tall, skinny guy instigate the fight.

    Tall, and fat, yes, short and fat, yes, muscular and any height, yes, but never tall and skinny. The more I think about it the build is the dominant factor in instigation.

  3. Steve,

    Thanks for the excellent comment. It emphasizes, I think, that the solution to prejudice isn’t lack of prejudice — it’s more and better prejudices.

    The FBI no longer tracks hispanics, but (using the proxy of New York City rates) we see the following ratios for felonious assault

    Race, % of Victims, % of Suspects
    Black, 47.4%, 54.2%
    Hispanic, 33.9%, 33.5%

    Implying that Hispanic are slightly underrepresented in terms of suspects (relative to background crime), while blacks are overestimated.

    But your point is what about build — where are those statistics?

    I don’t know. Perhaps it isn’t tracked? We are in a data desert, and we need more.


    As I mentioned, “There are remarkably easy ways to predict when some people have the wrong biases. But that is a post for a different time.” 😉

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