Scientists Measure the Accuracy of a Racism Claim


Scientists have often been accused of letting their ideology influence
their results, and one of the most famous cases is that of Morton’s
skulls — the global collection amassed by the 19th-century physical
anthropologist Samuel George Morton.





In a 1981 book, “The Mismeasure of Man,” the paleontologist Stephen Jay Gould
asserted that Morton, believing that brain size was a measure of
intelligence, had subconsciously manipulated the brain volumes of
European, Asian and African skulls to favor his bias that Europeans had
larger brains and Africans smaller ones. But now physical anthropologists at the University of Pennsylvania,
which owns Morton’s collection, have remeasured the skulls, and in an
article that does little to burnish Dr. Gould’s reputation as a scholar,
they conclude that almost every detail of his analysis is wrong.
“Our results resolve this historical controversy, demonstrating that
Morton did not manipulate his data to support his preconceptions, contra
Gould,” they write in the current PLoS Biology. Dr. Gould, who died in 2002, based his attack on the premise that Morton
believed that brain size was correlated with intelligence. But there is
no evidence that Morton believed this or was trying to prove it, said
Jason E. Lewis, the leader of the Pennsylvania team. Rather, Morton was
measuring his skulls to study human variation, as part of his inquiry
into whether God had created the human races separately (a lively issue
before Darwin decreed that everyone belonged to the same species).
In his book, Dr. Gould contended that Morton’s results were “a patchwork
of fudging and finagling in the clear interest of controlling a priori
convictions.” This fudging was not deliberate, Dr. Gould said, but
rather an instance of unconscious doctoring of data, a practice he
believed was “rampant, endemic and unavoidable” in science. His finding
is widely cited as an instance of scientific bias and fallibility.
But the Penn team finds Morton’s results were neither fudged nor
influenced by his convictions. They identified and remeasured half of
the skulls used in his reports, finding that in only 2 percent of cases
did Morton’s measurements differ significantly from their own. These
errors either were random or gave a larger than accurate volume to
African skulls, the reverse of the bias that Dr. Gould imputed to
Morton. “These results falsify the claim that Morton physically mismeasured
crania based on his a priori biases,” the Pennsylvania team writes.
Dr. Gould did not measure any of the skulls himself but merely did a
paper reanalysis of Morton’s results. He accused Morton of various
subterfuges, like leaving out subgroups to manipulate a group’s overall
score. When these errors were corrected, Dr. Gould said, “there are no
differences to speak of among Morton’s races.” But Dr. Gould himself omitted subgroups in his own reanalysis, and made
various errors in his calculations. When these are corrected, the
differences between the racial categories recognized by Morton are as he
assigned them. “Ironically, Gould’s own analysis of Morton is likely
the stronger example of a bias influencing results,” the Pennsylvania
team writes. Dr. Lewis, the lead author, said that on checking the references for
some of Dr. Gould’s accusations he found that Morton had not made the
errors attributed to him. “Those elements of Gould’s work were
surprising,” he said. “I can’t say if they were deliberate.” Dr. Lewis, who is now at Stanford University, began the project while at Penn. An earlier study by John S. Michael, then an undergraduate at Penn,
concluded that Morton’s results were “reasonably accurate,” with no
clear sign of manipulation. But when others suggested Dr. Gould had been
refuted, Philip Kitcher, a philosopher of science at Columbia
University, rode to his defense. “It is not entirely evident that one should prefer the measurements of
an undergraduate to those of professional paleontologist,” he wrote in
2004. “Pending further measurement of the skulls and further analysis of
the data, it seems best to let this grubby affair rest in a footnote.”
Dr. Kitcher said last week that the Penn team had done a “very careful
job” and that “it’s a nice thing that undergraduate work gets
vindicated.” As for the new finding’s bearing on Dr. Gould’s reputation, Dr. Kitcher
said: “Steve doesn’t come out as a rogue but as someone who makes
mistakes. If Steve were around he would probably defend himself with
great ingenuity.” But Ralph L. Holloway, an expert on human evolution at Columbia and a
co-author of the new study, was less willing to give Dr. Gould benefit
of the doubt. “I just didn’t trust Gould,” he said. “I had the feeling that his
ideological stance was supreme. When the 1996 version of ‘The Mismeasure
of Man’ came and he never even bothered to mention Michael’s study, I
just felt he was a charlatan.”