I was in Texas and Oklahoma last week. In the course of the trip, I was in a number of situations where I had to make conversation with people I didn’t know. Looking back on those conversations, I realize that when I was talking to white, male businessmen and needed to come up something to say, I generally chose the subject of college football.

For lack of a better word, let’s call this “conversational discrimination.” I don’t assume that every stranger I meet wants to talk about college football. But I drew an inference about my conversational partner, based on his membership in the “white-male-businessmen of Texas and Oklahoma group” and used that inference to direct my behavior. As Judge Posner reminded us, in his review of Blink, in situations where one doesn’t know a lot about an individual, it may “sensible to ascribe the group's average characteristics to each member of the group, even though one knows that many members deviate from the average.” As it turns out, my assumption was largely correct. I had lot of really great conversations about college football. (Let's be clear this was not a hardship: I'm happy to talk about college football until the cows come home).

The reason this stereotype was so useful was that I used as much of the available information about my conversational partner as I could. The fact that I was in Texas and Oklahoma mattered a lot. I wouldn’t have assumed that I could talk about college football with a similar group of white male business types from, say, Silicon Valley. The fact that they were businessmen mattered, and not, say, graphic designers or actors. The fact that they were men and not women mattered, and I know from experience that if I’m choosing a sports topic for conversation with an black male businessman, I’ll probably guess basketball—particularly if the person I’m talking to is from the East Coast. The point is the accuracy of stereotypes is a reflection—in large part—of their specificity: the more information you can use to build a generalization, the better off you are.

This is my third (and last) comment on the Ayres study. My first point, as those of you who have been following my thoughts on this know, is that price discrimination against black males by car salesmen is morally wrong. My second point is that it is a bad business strategy. My third—and in some ways most important point—is that its lousy stereotyping.

Let’s go back to the study. The male and female, black and white testers who Ayres sent out to car dealerships all gave the salesmen the same set of facts. They were all roughly the same age (late twenties). They all drove the same kind of car into the lot. They all dressed neatly and conservatively. They identified themselves as college-educated professionals (sample job: systems analyst at a bank). And they said they lived in the upper-income Chicago neighborhood of Streeterville. The car salesman, then, has several pieces of data from which to create his stereotype. He has the gender, race, age, occupation, educational level, and class (or at least a class proxy) of his potential customer. And what did he do? With the black men, he zeroed in on age and race, and ignored everything else.

In his critique of my analysis of Ayres, Judge Posner did the same thing. When he says that it may be “sensible to ascribe the group's average characteristics to each member of the group,” the “group” he’s talking about is race. But why is Posner—like the car salesmen—so hung up about race? Wouldn’t it be just as sensible, in the case of black men, to define their “group” as the group of college-educated, upper income professionals? So too with Steve Sailer. He says that car salesman are acting rationally, based on the fact that black men—as a group—like to be seen overpaying for cars. I have made my feelings known about what I see as the motivation behind that particular comment. But let’s just focus here on its appropriateness. Why is Sailer—like Posner and Ayres’car dealers—so intent on zeroing in on what is only one of many available and relevant facts about the customer?

The short answer to that question, I think, is that this is what racial prejudice is: it is the irrational elevation of race-based considerations over other, equally or more relevant factors.

But let me make two other points. First, thinking of the Ayres study this way gives us, I think, some insight into the anger that continues to be felt in the African-American community over discrimination. Put yourself in the shoes of one of those black males in Ayres study. You go to college. You get a good job. You make a lot of money. You move to a posh neighborhood. And when you walk into a car dealership all of those achievemens—and what they signal about you—vanish, and the salesmen only sees the color of your skin. Can you understand now why I’ve been hammering away on this subject?

Second, some of the commenters to my previous posts seem to have been of the opinion that price discrimination represented a kind of shrewd, profit-maximization strategy by salesmen. Shrewd? Tell me what’s so shrewd about being given four critical facts about a potential customer, and deciding to discard three of them?