Mann has lectured on this, encouraging his colleagues to be mindful of their field's past. But racism, he said, has infected other fields including biology and psychology.
The post about black women appeared May 15, authored by Satoshi Kanazawa, an evolutionary psychologist from the London School of Economics.
Kanazawa based his claim not on a published study but on his own analysis of a large survey by the Add Health group at the University of North Carolina. The vast survey started with seventh to 12th graders and followed them into adulthood, evaluating health along with social, economic, and psychological factors. For reasons that are unclear, the interviewers rated the subjects on attractiveness on a scale from 1 (very unattractive) to 5 (very attractive).
From this, Kanazawa concluded that black women are "objectively" less attractive than women of other races - despite the obviously subjective nature of the evaluation.
He also failed to mention that many of the evaluations were made while the subjects were teens, some as young as 12. The same subjects were evaluated at four intervals, and only in the last two of those were they all adults.
Another psychologist, New York University's Scott Barry Kaufman, reanalyzed the same data but removed the two parts that used teen subjects. In the two groups that were made up of only adults, he found no significant difference in perceived attractiveness among races. He also noted that Kanazawa left out one of the two all-adult groups in his analysis.
Kaufman presented this as a rebuttal on his own Psychology Today blog.
The incident shows some parallels to the case of Philly's skull-measuring anthropologist Morton. (His skull collection is still housed in the Penn Museum of Archaeology and Anthropology.) Morton thought he had evidence that, on average, Africans had smaller heads and were therefore less intelligent.
The abolition movement was growing then, and Morton was embraced by those who favored slavery, said Mann. Morton was also working under the theory that God created human races separately, making them essentially different species. Darwin's evolution theory was still years away.
At the time, it was a common assumption that head size correlated with intelligence. It does, roughly, across different animal species, though it's the size of the brain relative to the whole animal that's important rather than the sheer size.
In the human race, the biggest heads belong to the biggest people, said Mann, but not necessarily the brightest.
Even if Morton's assumption were correct and having a small head somehow disqualified a person from freedom, then Americans should have stopped kidnapping Africans and started measuring heads and enslaving those with the smallest. But that clearly wasn't his agenda.
In the 1980s, paleontologist Stephen Jay Gould attempted to debunk Morton in his book The Mismeasure of Man. Gould went so far as to claim that Morton fudged his data, but others, including Mann, have reexamined the evidence and say Morton was wrong not because he cheated but because he used skewed data and made bad assumptions.
A disproportionate number of his African skulls came from a relatively diminutive group, Mann said, and Morton might not have been aware of this.
People don't have to commit scientific fraud to get results in line with their prejudices, Mann said. "There are lots of scientists living in the last century who allowed their own personal biases to influence the way they saw things."
One difference between now and then is that Morton had respect from other scientists, while Kanazawa is considered on the fringe. "I can't think of one person who respects him as a scientist," said NYU's Kaufman. Penn evolutionary psychologist Rob Kurzban agreed. "My sense is that many people in the field don't think it's worth engaging with him."
On the other hand, both say he's one of the most popular bloggers at Psychology Today. "If you weren't familiar with the scholarly literature, and only looked at the popularity of the blog, you might think he was a lot more prominent in the field than he is," said Kurzban, who, like Kaufman, writes a much less popular blog on the same site.
Kanazawa's previous posts include such headlines as "Are All Women Essentially Prostitutes?" Psychology Today might have seen this as a red flag some time ago, but they continue to let him blog under their name. They eventually removed the post about black women with no explanation. They issued an apology on their website late last week, but Kanazawa's blog, "The Scientific Fundamentalist," remained on their site.
In response to questions, the magazine's editors sent The Inquirer a link to an NPR blog post, which contained the following quote from editor in chief Kaja Perina: "Our bloggers are credential[ed] social scientists" who choose their own topics, Perina wrote. "We in turn reserve the right to remove posts for any number of reasons. Because the post was not commissioned or solicited by PT (in contrast to a magazine article), there was no editorial intent to address questions of race and physical attractiveness."
Kanazawa did not respond to a request for an interview.
The controversy has fueled new criticism toward evolutionary psychology, a field that already has some vocal detractors. "Among the many reasons that I detest evolutionary psychology, one has a name: Satoshi Kanazawa," wrote biologist and blogger P.Z. Myers.
Other evolutionary psychologists say they're trying to expand the frontiers of human knowledge, and they can't avoid certain questions just because the answers might be hurtful.
But in an era when scientists are deciphering the fundamental constituents of matter, decoding the genome, and discovering planets sprinkled through the galaxy, anyone might wonder whether determining which race has hotter women is a reasonable endeavor for a grown man, let alone someone Psychology Today deems a credentialed scientist.
The only good news here, says Mann, is that racism will end eventually, since today's unprecedented mobility is melting us all together. "When you look at the latest census figures, an enormous number of people are reporting they have mixed backgrounds," he said. "What we're seeing is the end of race as we know it."
Contact staff writer Faye Flam at 215-854-4977 or email@example.com.