This is stemming from my post on "Lewontin's Fallacy" and the topic of race as a biologically valid category for humans (or, rather, why it is not). Within the last week, I continued to receive a small number of comments, many of them branching from an ad nauseam argument regarding forensic anthropologists' ability to identify the race of an individual by either examining certain genetic clusters that correlate with self-identified race, or by examining bone fragments or other anthropometric features. I've disabled comments now, because I had already stated that I wouldn't further entertain the discussion, but I feel that a further explanation is needed to kill this line of reasoning.
To begin, the reason a forensic anthropologist can identify "race" with a high level of confidence can be narrowed down to two things: (1) a preconception of what "race" is, and (2) an informative prior.
This is fairly well discussed in the article "Understanding Race and Human Variation: Why Forensic Anthropologists are Good at Identifying Race" by Ousley, Jantz and Freid in 2009. The authors do concede that there are rather unambiguous morphological differences between American blacks and American whites; however, they explain why this can be taken out of context:
"Part of the reason for the disagreement between forensic and biological anthropologists has been in their different approaches and goals. Forensic anthropologists answer practical questions of age, sex, and race to construct the biological profile and narrow down possible identifications. In examining American blacks and whites, forensic anthropologists would naturally think in terms of two biological races because of the concordance between social and morphological race. Identifying social race, available in missing persons reports, would be the stopping point. Biological anthropologists would explore within-group variation further. These findings illustrate the essential difference between a forensic analysis and a biological analysis: forensic analysis produces practical information useful for forensic identification, while a biological analysis provides insight about relationships among arbitrarily defined populations, which may be defined by social races, breeding populations, language, nationality, time periods, and other criteria." (pp. 73)
Forensics: Useful for practical reasons.
These comments serve to echo and confirm the findings of Sauer in 1992 in a paper entitled "Forensic Anthropology and the Concept of Race: If Races Don't Exist, Why are Forensic Anthropologists so Good at Identifying Them?" Humorously, I would like to note that the only mentioning you'll find of this study on Metapedia (or any study featured in the special edition of the American Journal of Physical Anthropology Race Reconciled) is that the name of this study shows how forensic identification has "bewildered race deniers." How selectively vague and uninformative, right? But enough of mocking "race realists" (lest I break my rule).
So, this is what it means to have a preconception of what race is. It means that a forensic anthropologist can both disagree with the biological concept of race, but also work very well within the confines of his/her work to identify someone's social race, and remain completely consistent. But, there remains a question to answer: if the biological concept of race is inaccurate, how can a forensic anthropologist find such high concordance rates between self-identified race and morphological race? Surely that means the traditional racial categories we use are useful, right?
They are meaningful, for identification purposes, and that only works within a given society. This goes into what I alluded to earlier: an informative prior. This one is a bit less obvious to work with, so I'll defer to a study also featured in Race Reconciled which explains this function of forensic anthropology: a 2009 study by Konigsberg et al. entitled "Estimation and Evidence in Forensic Anthropology: Sex and Race." Not only was this study an easy read, but it comprehensively explains what so many people don't understand.
This study discusses the identification of one "Mr. Johnson" from Iowa. Using craniometric features and matching them to the samples in FORDISC 2.0 and Howells' sample using linear and quadratic discriminant function analysis, forensic anthropologists were able to identify the gender and race of Mr. Johnson rather unambiguously. The posterior probability of the body being male ranged from 0.996 to 0.999 -- noting this, I would like to make it clear that it is not easier to identify race than it is to identify gender, unlike what some might suggest. This part was rather uncomplicated by comparison, however, when we get into the identification of race, my talk of an informative prior becomes relevant.
By matching to the sample data, the typicality of Mr. Johnson relative to the Easter Islander sample was 0.8415, indicating a high probability that Mr. Johnson could be correctly identified, if he were alive, as an Easter Islander. This is, however, using a uniform prior, i.e. no informative information about the demographics of the area Mr. Johnson was found in. Given that Mr. Johnson was found in eastern Iowa, the probability of him being an Easter Islander significantly decreases -- that's just a matter of knowing the demographics of Iowa. To continue, what does this do to the typicality of Mr. Johnson's craniometric features?
By using the 2000 US census for Iowa as an informative prior, the highest posterior probability for Mr. Johnson is for "American white" at 0.6976, whereas the probability of him being an Easter Islander is now at 0.0449. This is an incredibly significant change considering the posterior probability we had using the uninformative prior. How do these probabilities change depending on the prior we use?
|Mr. Johnson's race somewhat 'transforms' from state to state.|
"From an evidentiary standpoint, sex of the individual is only of much use if the sex ratio is very biased for the population at large and the identification is for an individual of the lesser represented sex. Regarding the use of race in estimation and evidentiary problems, this, like many problems in forensic anthropology is very context specific. We have shown that prior information can be very important both in estimation and evidentiary problems. But in estimation problems, we are ultimately faced with posterior probabilities which we must decide how how to implement." (pp. 84)
Let me stress the significance of those words. Using race in forensic anthropology is largely reliant on probabilities, and even then, it requires context.
This is why I get somewhat tired and irritated when, while debating about race, a sentence starts with "a forensic anthropologist can-" or even mentions forensic anthropology at all. Within the field of anthropology, there exists "social race" and "biological race." Forensic anthropologists more often than not are using morphological features to identify social race, that is, the race the individual would've been identified as had they been alive. This is why informative priors can change the probability estimates -- because an individual's social race is quite fluid; therefore, it does not justify race as a biological concept.
Thank you for reading.
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Konigsberg, L., Algee-Hewitt, B., & Steadman, D. (2009). Estimation and evidence in forensic anthropology: Sex and race. American Journal of Physical Anthropology, 139 (1), 77-90 DOI: 10.1002/ajpa.20934
Ousley, S., Jantz, R., & Freid, D. (2009). Understanding race and human variation: Why forensic anthropologists are good at identifying race. American Journal of Physical Anthropology, 139 (1), 68-76 DOI: 10.1002/ajpa.21006
Sauer, N. (1992). Forensic anthropology and the concept of race: If races don't exist, why are forensic anthropologists so good at identifying them? Social Science & Medicine, 34 (2), 107-111 DOI: 10.1016/0277-9536(92)90086-6