Category Archives: Evolution and Genomics

Attempting a constructive take on the Sam Harris/Ezra Klein/IQ disagreement. The Nerd and the Manager.

Image source: Sam Harris podcast, Ezra Klein podcast

Section 1. The backstory.

Last year Sam Harris had Charles Murray on his podcast to talk about IQ, race and Murray’s reputation. Vox published a critique. Also see the counter, and the counter counter. Then last week, spurred on by a twitter discussion of David Reich’s new book, Ezra Klein wrote 6000 words Sam Harris, Charles Murray, and the allure of race science. Harris responded by publishing their email correspondence. Which mostly backfired. So yesterday Harris announced on his podcast he has invited Klein to be his guest. That podcast will be recorded in a day or two, around April 5 or 6. It should be excellent because Ezra Klein and Sam Harris are both first rate, very sharp, and extremely reasonable. I highly recommend both their podcasts. And yet, I’m pessimistic. [Update. Podcast with transcript here.]

Why? Let me attempt a (hopefully) constructive explainer. Thus I’ll crib the voxsplainer format for this post. Don’t be a hater.

Section 2. The Nerd and the Manager.

If you read the Klein/Harris published email exchange, you’ll note one person is arguing in what I’d call nerd-mode, the other in manager-mode. Everyone uses both modes. But for a civil discussion both people need use the same mode.

When Ezra Klein talks healthcare, he’s in nerd-mode. In the weeds. He made his name blogging about healthcare. He knows all the policy details. So for healthcare he can argue with experts, and critique them. But when Klein is talking race and IQ, he’s in manager-mode. Let me quote from his email to Harris:

Which brings me to the podcast. I really think that core discussion over the scientific dispute here is the important one, and I don’t want to present myself as the best person to have it. So to the extent I can persuade you that the disagreement is legitimate and good faith, I still think an actual expert in this field would be a better guest than me. The Heier note and Flynn piece only underscores the point: there are clearly experts on both sides of this, and I think there is something in the non-Murray side’s presentation you are having trouble hearing as serious, or as honest, and I think finding the boundaries of that disagreement would be the most interesting and enlightening conversation here. I am not a race and IQ expert and don’t play one on podcasts, so I don’t want to be the other side of that debate.

Manager-mode is about social proof. A manager knows how to listen to a team of experts and build a consensus. Or barring consensus, can select which expert(s) to follow. But a manager is not an expert. Klein says experts from the Vox piece disagree with the experts Harris cites. Harris replies:

As a point of comparison, you can see how Siddhartha Mukherjee handled Murray in his book The Gene, and in my most recent podcast with him. As I told Mukherjee, I don’t think he was fair to Murray, and I think he is bending too far in his definition of “intelligence,” but the discussion was far more respectful and balanced (and honest) than what you published in Vox.

Why not publish Haier’s rebuttal? His presentation of the science is far more mainstream that Nisbett’s (or Mukherjee’s, for that matter).

Harris’ is talking in nerd-mode. Harris knows the details. He knows which experts are right, which are wrong, which are spinning. And when you’re in nerd-mode (as I am right now writing this post), you find it nearly impossible to understand why anyone can disagree with your facts. You’re reluctantly led to conclude lingering disagreement must be due to ill motives. Trust me. I use twitter. I’ve spent plenty of time in nerd-mode hell.

But of course in real life human cognition is highly evolved to swim in the ocean of social proof.  We mostly live in manager-mode. We it take for granted the views of our in-group are correct. This dynamic appears to me to explain what happened. Harris published the emails in nerd-mode. That backfired because most people read them in manager-mode, which was the mode Klein was using at the time.

This bodes ill for the upcoming Harris-Klein podcast. Harris will argue expert details. Klein will respond by pointing out to experts who disagree. But there may be a way out.

Section 3. Music break.

But first. All good Voxsplainers have a 1990’s music break. Here’s mine.

The awesomeness of Weezer shall not be denied. On to section 4.

Section 4. Framing the IQ debate around what’s changed since 1994.

The Bell Curve was written 24 years ago in 1994. Perhaps we can reconcile nerd-mode and manager-mode by looking at trends over time. The nerd can point to changing details. The manager can point to changing scientific/public consensus. Both can be happy.

By far the most popular critique of The Bell Curve when it came out was the New Yorker piece by Stephen J Gould. Take my word for it. I remember 1994. In fact I bought Weezer’s first album on a plastic disc in 1994 when it came out. It remains excellent. But I digress. Back to Gould. Scroll down to the Appendix below to read Gould’s original words (nerd-mode people only of course). Or just use my bullet point summary of Gould right here:

  1. The claim that IQ and g can use a single number to measure something real in the brain is a fallacy. “Nothing in The Bell Curve angered me more”
  2. Racial differences in IQ being mostly determined by genetic causes “is most surely fallacious”
  3. Murray claims social stratification based on IQ will occur because meritocracy selects for it. This requires that IQ “must be depictable as a single number, capable of ranking people in linear order, genetically based, and effectively immutable.” And “The central argument of The Bell Curve fails because most of the premises are false”

Now compare this to the Vox piece authored by Eric Turkheimer, Kathryn Paige Harden, and Richard E. Nisbett. Call it the THN piece after their last initials. Fortunately they bullet pointed their argument as below:

Murray’s premises, which proceed in declining order of actual broad acceptance by the scientific community, go like this:

1) Intelligence, as measured by IQ tests, is a meaningful construct that describes differences in cognitive ability among humans.

2) Individual differences in intelligence are moderately heritable.

3) Racial groups differ in their mean scores on IQ tests.

4) Discoveries about genetic ancestry have validated commonly used racial groupings.

5) On the basis of points 1 through 4, it is natural to assume that the reasons for racial differences in IQ scores are themselves at least partly genetic.

Until you get to 5, none of the premises is completely incorrect. However, for each of them Murray’s characterization of the evidence is slanted in a direction that leads first to the social policies he endorses, and ultimately to his conclusions about race and IQ. We, and many other scientific psychologists, believe the evidence supports a different view of intelligence, heritability, and race.

For comparison, here is Harris’ summary of Murray’s thesis:

  1. Human “general intelligence” is a scientifically valid concept.
  2. IQ tests do a pretty good job of measuring it.
  3. A person’s IQ is highly predictive of his/her success in life.
  4. Mean IQ differs across populations (blacks < whites < Asians).
  5. It isn’t known to what degree differences in IQ are genetically determined, but it seems safe to say that genes play a role (and also safe to say that environment does too).

What has 24 years wrought? I’d say Gould’s critique of IQ has fallen completely outside of acceptable scientific and social discourse. IQ is a meaningful construct is explicitly agreed to by THN in their 2018 critique of Murray. Gould’s two other points haven’t aged well either.

Now compare THN to Harris. The first 4 points from THN are similar to the first 4 from Harris. These are relatively secure. Though as noted by THN , experts differ on how strong they think those 4 claims are. But the 5th claim from THN and the 5th claim from Harris remain in public dispute. Namely, to what degree do IQ group difference have a genetic component, if any. This is disputed almost by definition since Turkheimer, Nisbett and Harden are in fact experts and they say it’s in dispute. So arguing in manager-mode, it makes perfect sense for Klein to justify his position. To add some additional social proof, here’s Kevin Drum saying the same thing in a recent short post. #5 is not mainstream public consensus.

One more point. In Klein’s 6000 word post on the allure of race science, he says:

Here is my view: Research shows measurable consequences on IQ and a host of other outcomes from the kind of violence and discrimination America inflicted for centuries against African Americans. In a vicious cycle, the consequences of that violence have pushed forward the underlying attitudes that allow discriminatory policies to flourish and justify the racially unequal world we’ve built.

To put this simply: You cannot discuss this topic without discussing its toxic past and the way that shapes our present.

I’d put it more bluntly. When you talk about IQ and race, you are providing (if misused) weapons of mass destruction to the worst elements of American society, both past and present. So if you decide to write about IQ, you can’t avoid talking about racism since anything you say can be weaponized. Which is why I needed to say so right here in my blogexplainer as well. Klein is correct about this.

Section 5. Where is IQ science going next.

Klein and Harris qualify as public intellectuals. But academics are the ones who define the acceptable limits of scientific discourse in their area of expertise. I follow Erik Turkheimer and Paige Harden on twitter, and it’s clear to me they wrote their article in a spirit of public service. And similarly, David Reich’s new book is public outreach as well. Academic outreach is a thankless task. Your colleagues claim you seek controversy to sell books. Partisans attack you. You can do permanent damage to your career.

It’s human nature to remember who your enemies are, even after you forget why. Read Ezra Klein’s excellent piece How politics makes us stupid, on Dan Kahan’s work. So even if our understanding of IQ continues to shift over time, I doubt existing reputations will change, for Murray or anyone else. There are always new (and old) reasons to dislike your out-group (1,2,3). [Update. Along those lines, Matthew Yglesias just wrote a post taking Murray to task not for his IQ position, but for his social policies, The Bell Curve is about policy. And it’s wrong.]

On the plus side, as Razib Khan noted recently on twitter, the public clearly benefits from academic public engagement. So I hope more academics reach out, despite the risks. And I hope Harris and Klein continue their work as public intellectuals, finding some common ground. Ideally talking nerd-mode to nerd-mode, or manager-mode to manager-mode. Perhaps even reviewing the history and possible future of IQ science. [Update. Peak manager-mode from the actual podcast was when Klein said “To prepare for this conversation, I called Flynn the other day. I spoke to him on Monday.”]

So let’s finish by asking where is IQ science going? Answer: genomics, genomics, genomics. Polygenic scoring. Embryo selection for IQ.

But we are not there yet. To see why read this piece by Antonio Regalado DNA tests for IQ are coming, but it might not be smart to take one.


Appendix. Gould’s 1994 critique of The Bell Curve.

Here’s key quotes from Gould’s 1994 critique of The Bell Curve, plus a link to the full article. Here’s Gould:

The Bell Curve rests on two distinctly different but sequential arguments, which together encompass the classic corpus of biological determinism as a social philosophy. The first argument rehashes the tenets of social Darwinism as it was originally constituted……The theory arose from a paradox of egalitarianism: as long as people remain on top of the social heap by accident of a noble name or parental wealth, and as long as members of despised castes cannot rise no matter what their talents, social stratification will not reflect intellectual merit, and brilliance will be distributed across all classes; but when true equality of opportunity is attained smart people rise and the lower classes become rigid, retaining only the intellectually incompetent…..
The general claim is neither uninteresting nor illogical, but it does require the validity of four shaky premises, all asserted (but hardly discussed or defended) by Herrnstein and Murray. Intelligence, in their formulation, must be depictable as a single number, capable of ranking people in linear order, genetically based, and effectively immutable. If any of these premises are false, their entire argument collapses. For example, if all are true except immutability, then programs for early intervention in education might work to boost IQ permanently, just as a pair of eyeglasses may correct a genetic defect in vision. The central argument of The Bell Curve fails because most of the premises are false…..
Herrnstein and Murray’s second claim, the lightning rod for most commentary extends the argument for innate cognitive stratification to a claim that racial differences in IQ are mostly determined by genetic causes—small difference for Asian superiority over Caucasian, but large for Caucasians over people of African descent. This argument is as old as the study of race, and is most surely fallacious.
Nothing in The Bell Curve angered me more than the authors’ failure to supply any justification for their central claim, the sine qua non of their entire argument: that the number known as g, the celebrated “general factor” of intelligence, first identified by British psychologist Charles Spearman, in 1904, captures a real property in the head.
I closed my chapter in The Mismeasure of Man on the unreality of g and the fallacy of regarding intelligence as a single–scaled, innate thing in the head….



Homo naledi and the braided stream of humanity. It’s miscegenation all the way down.

image source

Above are reconstructions of three famous fossil hominins by paleo-artist John Gurche. From left to right: Australopithecus afarensis (Lucy), Homo erectus (Turkana boy) and recently discovered Homo naledi (paper). The Homo naledi announcement last month of fossils discovered in a cave in South Africa was a blockbuster for human origins. Even better, two more big origins papers were published in the past two weeks. The first on the oldest modern human teeth found in China, pushing the date of modern humans in Asia from ~45,000 to 80-100,000 years ago (paper). The second on the genome of a 4,500 year old Ethiopian (paper).

Continue reading Homo naledi and the braided stream of humanity. It’s miscegenation all the way down.

Homo Erectus – not so different from modern humans


Ancient Greeks believed ”whoever is not Greek is a barbarian.” Viewing other groups as subhuman is as old as humankind. In fact one way to measure historical progress is to note the expanding definition of what it means to be human, including more races, genders, cultures. Today we include every human on the planet. But let’s take this down another axis, into our evolutionary past. If we could magically resurrect our evolutionary forebears, how far back could we go before we’d have to admit these are apes, not people? It’s a thought experiment. Arguably we could call Homo Erectus close to modern, even though it’s one of the first in the genus homo.

Continue reading Homo Erectus – not so different from modern humans

In favor of the Super Early Anthropocene

super city

The Anthropocene is a proposed epoch to add to the Geologic Time Scale (GTS), marking the start of human dominance of Earth’s climate and ecology. Our current Holocene epoch started 11,700 years ago and runs to present. At this point it seems likely the International Commission on Stratigraphy, which decides such things, will approve the Anthropocene epoch. But picking the start date has led to debate. The likely winner is roughly 1800, tied to the start of the industrial revolution and it’s steep rise in greenhouse gases. But William Ruddiman advocates an “Early Anthropocene”, starting around 8000 years ago when agriculture got started. For what it’s worth, I’m in the super early camp, and would argue the entire Holocene itself (from 11,700 years ago) should just be lumped in with the Anthropocene. Us humans have been wreaking havoc for a long, long time.

Continue reading In favor of the Super Early Anthropocene

Race and IQ. Can’t we all just get along?


Jason Richwine resigned from the conservative Heritage Foundation a few weeks ago because his PhD thesis titled IQ and Immigration Policy came to light with this choice media quote: “No one knows whether Hispanics will ever reach IQ parity with whites, but the prediction that new Hispanic immigrants will have low-IQ children and grandchildren is difficult to argue against.” This kicked off predictable diatribes on race and IQ from both sides. So what’s new? Especially since I’ve already posted on genetics and intelligence before. Well the last major go round from 1994’s The Bell Curve was pre-twitter/early blog. So following this round live in the blogosphere gave a more nuanced view of where people are coming from. Hence the modest goal of this post is outlining the stronger arguments on race and IQ from both liberals and conservatives. Though with little expectation of changing anyone’s mind, including my own. Maybe I’m just getting old, but nowadays I’m feeling a deeper and deeper sympathy for Rodney King’s famous line pictured above.

Continue reading Race and IQ. Can’t we all just get along?

What are the risks of a global pandemic?


David Quammen’s latest book Spillover: Animal Infections and the Next Human Pandemic is wonderfully written. As expected from someone the New York Times says “is not just among our best science writers but among our best writers, period.” And the Times is right, Quammen is awesome. I loved his widely praised The Song of the Dodo: Island Biogeography in an Age of Extinction. A mashup of nature travel, science and adventure that really works.The place to start if you haven’t read Quammen. Spillover uses the same template, but is not nearly as good. It’s drags and could have been cut by a third. But worse is the alarmist take on the risks of a pandemic. Some historical and evolutionary context will explain my reaction.

Continue reading What are the risks of a global pandemic?

What sport are humans best evolved for?


Cheetahs are the fastest land animal. Sailfish the fastest swimmers. Pumas the highest jumpers. So which sport do humans excel at? Slate claims it’s endurance running. They made this claim as part of their coverage of the totally awesome Man versus Horse marathon, a 22 mile long annual Welsh race of humans versus horses. Now of course picking which sport we’re best evolved for is rather silly, but it’s also interesting if you think about it. Since I’ve seen this topic before, I wanted to give my pick.

Continue reading What sport are humans best evolved for?

Perfect meritocracy replaces class with caste


The still above is from the movie The Time Machine based on H.G. Wells’ book. It’s the scene where the uber-Morlock meets the time traveling human, who had been hanging out with the Eloi. This dystopia came to mind as I was thinking about Razib Khan’s post “The end of environmental inequality means the rise of genetic inequality”. I want to shamelessly steal from Khan’s post to do my own version, since it’s a disturbing way to think about rising inequality. In fact the title of this post is a shortened version of Khan’s last sentence: A perfect meritocracy would replace cultural class with biological caste.

Continue reading Perfect meritocracy replaces class with caste

The Genomic Tsunami. Reshaping arguments for Human Equality.


This is part 3 of a 3 part series. Part 1 is here. Part 2 is here.

In part 1, we saw how the 10,000 fold decease in genome sequencing costs is creating a golden age for genomics biology. In part 2, we reviewed recent debates about race, genetics and intelligence. Now we can put this together and see how the genomic tsunami is reshaping existing arguments around genes, race, intelligence and human equality.

Continue reading The Genomic Tsunami. Reshaping arguments for Human Equality.