Stephen Jay Gould famously argued in his best-known work, The Mismeasure of Man, that Samuel Morton unconsciously manipulated his data on cranial capacity in different populations to fit his own preconceived, racist notions about human variation. Gould undertook a reanalysis of Morton's data and leveled a variety of accusations against Morton: he incorrectly measured skulls, made mathematical errors, picked and chose his sample populations, and didn't report all of the data he collected. I would be surprised if any biological anthropologist did not have to read The Mismeasure of Man in a college or graduate course somewhere along the line. I've even assigned chapters from it when teaching my own classes as well. The Gould vs. Morton case is often used to illustrate that scientists are humans and humans can be biased.
Yesterday, an article by Jason Lewis and colleagues came out in PLoS Biology contradicting Gould's conclusions about Morton: "The Mismeasure of Science: Stephen Jay Gould versus Samuel George Morton on Skulls and Bias". The authors remeasured Morton's skulls and reanalyzed both Morton's and Gould's data and have concluded that Gould's claims about Morton's bias are either poorly supported or falsified. It's a fascinating read, particularly the powerful last paragraphs:
[...] Our results falsify Gould's hypothesis that Morton manipulated his data to conform with his a priori views. The data on cranial capacity gathered by Morton are generally reliable, and he reported them fully. Overall, we find that Morton's initial reputation as the objectivist of his era was well-deserved.
That Morton's data are reliable despite his clear bias weakens the argument of Gould and others that biased results are endemic in science. Gould was certainly correct to note that scientists are human beings and, as such, are inevitably biased, a point frequently made in “science studies.” But the power of the scientific approach is that a properly designed and executed methodology can largely shield the outcome from the influence of the investigator's bias. Science does not rely on investigators being unbiased “automatons.” Instead, it relies on methods that limit the ability of the investigator's admittedly inevitable biases to skew the results. Morton's methods were sound, and our analysis shows that they prevented Morton's biases from significantly impacting his results. The Morton case, rather than illustrating the ubiquity of bias, instead shows the ability of science to escape the bounds and blinders of cultural contexts.Morton's study of skulls published in Crania Americana seems to have been grounded in good science after all. His interpretation of the differences he saw, however, was not. We know now - thanks in large part to Franz Boas, the father of American anthropology - that environment most directly influences the size and shape of one's skull, not one's "race" or ethnic background. The study by Lewis and colleagues, though, shows that Gould's interpretations may have been as clouded as Morton's, and it seems that Gould may have set up a straw man in Morton, attacking his science rather than his interpretations.
Anyone out there who's read The Mismeasure of Man should read the eye-opening PLoS article. It might change the way you think about bias in scientific studies.
UPDATES (6/9/11) - Some other awesome bloggers have written about this too, including Dienekes Pontikos and John Hawks. The Penn Museum, where the Morton collection is curated, has a press release on it and a blog post as well.
UPDATE (6/13/11) - Dienekes also posted a link to a c. 20-minute interview on the Morton Collection of skulls at Penn.
UPDATE (6/14/11) - NY Times coverage of the article.
J.E. Lewis, D. DeGusta, M.R. Meyer, J.M. Monge, A.E. Mann, & R.L. Holloway (2011). The Mismeasure of Science: Stephen Jay Gould versus Samuel George Morton on Skulls and Bias PLoS Biology, 9 (6) : 10.1371/journal.pbio.1001071