Neil deGrasse Tyson on reviving public interest in science (and other stuff)

April 19, 2021 • 12:45 pm

The New York Times has a long interview with astrophysicist Neil deGrasse Tyson about many things, but the main topic is how to revive what’s seen as waning public interest in science as well as distrust of science. Click on the screenshot to read it:

Perhaps unsurprisingly, given that this is the NYT, a lot of the interview is about two claims of sexual misconduct made against Tyson a few years ago. As the article notes, these claims were investigated by three bodies: the American Museum of Natural History, where Tyson works, and National Geographic and Fox News (the latter two air his shows); and there was no finding of misconduct. Yet the NYT brings it up in the first paragraph, and then later on asks him several questions that have nothing to do with science, questions that Tyson deftly deflects. Before we get to the science, here are the questions (note that the link doesn’t seem to work)

  • A lot of what we’ve talked about really goes to questions of authority. Do you feel as if your own authority was affected by the claims of sexual misconduct made against you a couple of years ago? 
  • What about from a perspective of curiosity? Did you learn anything about gender dynamics or power imbalances as a result of those accusations? 
  • But I was trying to ask what younot the culture, had learned. Did that experience open any self-reflection or new understanding about either your own behaviors or thinking regarding gender dynamics? I’m trying to get some introspection. 

Tyson answers them (or rather circumvents them), but what do they have to do with the topic of the interview? Given that he was exculpated, it’s time to leave the guy alone about this stuff.

There are other questions about the search for extraterrestrial life, the connection between relativity and quantum mechanics, and the way to popularize science—the main point of the interview.

So is the public really mistrustful of science or scientists? A Pew Poll from last year says “no, not really”, for public confidence in the ability of scientists to act in the public interest rose in the four years between 2016 and 2019 and it’s high. In fact, the only group that inspires more confidence are K-12 school principals (politicians are especially low!):

Now this was before the pandemic hit, so the data may differ now. And we’re surely aware that the public is suspicious of vaccines, which I suppose reflects a lack of confidence not in medical scientists, but in public health officials. Further, most people are taking their shots, which shows a pretty remarkable confidence in science given that the vaccines were developed over a couple of weeks before they were tested.

I don’t perceive a public distrust of science so much as a public lack of interest in science. No matter how many Tysons, Sagans, and Dawkinses you throw at the public, some people will just never get turned on. And there’s no way to force them to be. People’s interests differ. Nevertheless, the three names I’ve just mentioned show that although we can’t get everyone on board with science, there is a latent interest out there that can be switched on.

How should we do that? There are a number of ways (my view is that each scientists should do outreach the best way they know how), but Tyson has a more definitive answer, which he imparts in this exchange (interviewers statement is in bold, Tyson’s response in regular type):

. . . Once you’ve come up knowing the science and how and why it works and understanding what the bleeding edge of science does, you’re in a position to pass judgment on science-related news. Now, on top of that, if there’s anything we would call a scientific authority, it is the National Academy of Sciences. Most people don’t even know that the frickin’ thing exists. Why is that? We need better marketing.

What would be the mechanism for that? I’ll go pie in the sky: a mission to Mars with humans. That would do it. Why do I know that? Because in the 1960s, while we’re going to the moon, you didn’t need special programs to get people interested in science and engineering. It was writ large in the daily headlines because every mission was more ambitious than the previous mission. This went higher, this orbited longer, now we’re docking, now we’re going to launch the craft that’s going to the moon, now we go to the moon. And you knew it was fluency in science and technology that was empowering that journey. So a mission to Mars with humans, I could script this: We’re going to do this in the year 2035. It’s 14 years from now, and we want the crew to be in their upper 20s in age, which means that right now that crew is in middle school. Let us do another Mercury 7 except we’re going to find the middle-schoolers who we are going to track, and Teen Beat is going to say, “How were your grades? Are you doing all the right things? Are you studying?” They become models for society without having to take out an ad. They go to Mars! By the way, for this you also need biologists, medical doctors, engineers, astrophysicists, chemists, geologists. You tickle all the STEM fields, and everybody is going to want to be a part of that, and science would reign supreme once again.

Yes, that is pie in the sky! First of all, a mission to Mars with humans, though it will undoubtedly pique public interest, will be not only expensive, but also dangerous.  And it will take seven months each way. The possibility of a disaster seems to me quite high. What we see here is what would get Tyson turned on, but not necessarily people like me.

But will a Mars mission really inspire interest in science—even over the long 14 years that Tyson says it would take to launch the mission? I don’t think so. Moreover, will it inspire the kind of interest in science that I would like to see: interest in the wonders of life and of evolution? (We each have our own fiefdom.) I don’t see how, even if Tyson says “you need biologists, chemists, and so on” to be part of a mission to Mars.

The fact that interest in evolution has been dialed up so high by Richard Dawkins, for instance, shows that you don’t need missions to Mars to get people excited about science. You just need a communicator with the knowledge, the eloquence, and the charisma to show people what excites us scientists without being condescending towards the public. In the past, those people have been largely physicists: people like Tyson, Sagan, or Feynman. But they needn’t be. The only prescription I’ll issue for exciting public interest in science is for scientists to stop considering outreach as an inferior activity. After all, it’s the public who funds our research, and why shouldn’t those of us who can help pay them back by telling them where their bucks went, and why?

Your turn. What turned you on to science? Are there things we should be doing to awaken interest in the field, but are not doing? Weigh in below.

Why science needs philosophy: an op-ed in PNAS

September 11, 2020 • 1:00 pm

Although some scientists (I believe Lawrence Krauss is one) have said that philosophy is useless to scientists, I’m not one of these miscreants. Although I recognize that philosophy can’t find out truths about the real world as opposed to “truths” within logical systems, it can certainly be an aid to thinking about science. Two examples are Dan Dennett’s ideas about consciousness (I don’t think his lucubrations about free will, though, have been helpful to science as opposed to philosophy itself) and Phil Kitcher’s critique of sociobiology (now “evolutionary psychology”) in his book Vaulting Ambition: Sociobiology and the Quest for Human Nature. 

Further, philosophers have been instrumental in helping discredit Intelligent Design theory and creationism; I’m thinking in particular of Rob Pennock’s book Tower of Babel: The Evidence Against the New Creationism and Kitcher’s anti-creationist book Abusing Science: The Case Against Creationism.  Surely dispelling an “alternative” theory to evolution is a real contribution to science and to science education.

My Ph.D. advisor, Dick Lewontin, was a big fan of philosophy, and some of his scientific papers, like the one on the units of selection, sit at the border of science and philosophy. We often had philosophers spending sabbaticals in our lab (Eliott Sober, one of the authors of the paper below, was one of them), and their presence was stimulating.

Now several scientists and philosophers have teamed up to once again make the case for the value of philosophy in science in this paper in the new PNAS. Click on the screenshot to read the piece, or download the pdf here.

It’s a short piece—3.5 pages long—and gives several examples, new to me, about how philosophers have helped guide research, mainly by clarifying concepts. Not all of the “helpful” aids from from philosophy seem to have been all that helpful, though, including debates about the “modularity” of the brain, or emphasis on the importance of microbes in the biosphere, which seems to me to have come from science, not philosophy. This is what the piece says about brain modularity, for instance:

Philosophy had a part in the move from behaviorism to cognitivism and computationalism in the 1960s. Perhaps most visible has been the theory of the modularity of mind, proposed by philosopher Jerry Fodor (10). Its influence on theories of cognitive architecture can hardly be overstated. In a tribute after Fodor’s passing in 2017, leading cognitive psychologist James Russell spoke in the magazine of the British Psychological Society of “cognitive developmental psychology BF (before Fodor) and AF (after Fodor)” (

Modularity refers to the idea that mental phenomena arise from the operation of multiple distinct processes, not from a single undifferentiated one. Inspired by evidence in experimental psychology, by Chomskian linguistics, and by new computational theories in philosophy of mind, Fodor theorized that human cognition is structured in a set of lower-level, domain-specific, informationally encapsulated specialized modules and a higher-level, domain-general central system for abductive reasoning with information only flowing upward vertically, not downward or horizontally (i.e., between modules). He also formulated stringent criteria for modularity. To this day, Fodor’s proposal sets the terms for much empirical research and theory in many areas of cognitive science and neuroscience (1112), including cognitive development, evolutionary psychology, artificial intelligence, and cognitive anthropology. Although his theory has been revised and challenged, researchers continue to use, tweak, and debate his approach and basic conceptual toolkit.

Well, modularity could have been true in principle, and surely the idea of brain modularity has stimulated a lot of discussion. But in the end, it hasn’t led anywhere, largely because the actions of the brain don’t seem to be separated into distinct, quasi-independent moieties but seem to be diffuse—and plastic enough to be influenced by other parts of the brain. You can read about this diffuseness in Matthew Cobb’s new book, The Idea of the Brain. But even the precise definition of modules isn’t sufficiently specific that philosophers have been able to propose good experiments to test it.

In the end, the authors offer some suggestions for how to make science and philosophy more of BFFs, and they’re reasonable but nothing that doesn’t come to mind—or haven’t come to mind—to others. For what they’re worth, here they are (my emphasis):

  • i) Make more room for philosophy in scientific conferences. This is a very simple mechanism for researchers to assess the potential usefulness of philosophers’ insights for their own research. Reciprocally, more researchers could participate in philosophy conferences, expanding on the efforts of organizations such as the International Society for the History, Philosophy, and Social Studies of Biology; the Philosophy of Science Association; and the Society for Philosophy of Science in Practice.

  • ii) Host philosophers in scientific labs and departments. This is a powerful way (already explored by some of the authors and others) for philosophers to learn science and provide more appropriate and well-grounded analyses, and for researchers to benefit from philosophical inputs and acclimatize to philosophy more generally. This might be the most efficient way to help philosophy have a rapid and concrete impact on science.

  • iii) Co-supervise PhD students. The co-supervision of PhD students by a researcher and a philosopher is an excellent opportunity to make possible the cross-feeding of the two fields. It facilitates the production of dissertations that are both experimentally rich and conceptually rigorous, and in the process, it trains the next generation of philosopher-scientists.

  • iv) Create curricula balanced in science and philosophy that foster a genuine dialogue between them. Some such curricula already exist in some countries, but expanding them should be a high priority. They can provide students in science with a perspective that better empowers them for the conceptual challenges of modern science and provide philosophers with a solid basis for the scientific knowledge that will maximize their impact on science. Science curricula might include a class in the history of science and in the philosophy of science. Philosophy curricula might include a science module.

  • vRead science and philosophy. Reading science is indispensable for the practice of philosophy of science, but reading philosophy can also constitute a great source of inspiration for researchers as illustrated by some of the examples above. For example, journal clubs where both science and philosophy contributions are discussed constitute an efficient way to integrate philosophy and science.

  • vi) Open new sections devoted to philosophical and conceptual issues in science journals. This strategy would be an appropriate and compelling way to suggest that the philosophical and conceptual work is continuous with the experimental work, in so far as it is inspired by it, and can inspire it in return. It would also make philosophical reflections about a particular scientific domain much more visible to the relevant scientific community than when they are published in philosophy journals, which are rarely read by scientists.

The first two are fine; as I said, Lewontin’s lab always had a philosopher about. Co-supervision of Ph.D. students would be practical only if one’s thesis had a big philosophical component. #4, a curriculum balanced in science and philosophy, sounds good but there is little time in graduate school for courses outside one’s area, so a roughly equal “balance” would be impractical. A single course in philosophy of science, however, would be useful for Ph.D. candidates, at least in evolutionary biology. Reading groups are great if they’re well supervised, and many science journals already adhere to #6, having some bits about philosophy.

In the end, philosophy is an extremely valuable adjunct to science, but useful largely for getting us to think hard and avoid blind alleys, not so much in providing answers or suggesting experiments. Giving answers to empirical questions is not, of course, the job of philosophy, which is why Francis Crick is supposed to have made this statement, which may be apocryphal:

“Listen to philosophers’ questions, but not to their answers.”

h/t: Bryan

Good news about the teaching of evolution in American public schools

August 9, 2020 • 11:45 am

A new report from the journal Evolution: Education and Outreach gives some pretty good news about the state of evolution teaching in American high schools. In particular, in two surveys of teaching methods published 12 years apart (2007 vs. 2019), the number of hours that teachers devote to the subject of evolution has become greater, the proportion of teachers presenting evolution as “settled science” as opposed to something more dubious has increased, and the presentation of creationism or Intelligent Design as valid alternatives to evolution has diminished, as has the proportion of teachers sending “mixed messages” about evolution. Click on the screenshot below to get free access to the article, and you can download the pdf here.

The authors wanted to survey how evolution was presented because several events over the 12-year period could have affected it. First, in 2005 there was the Kitzmiller v. Dover case, in which the judge ruled that Intelligent Design (ID) was not science. It likely took a few years for that ruling to seep into high schools throughout the U.S. (Happily, the legal battles over teaching creationism in public schools appear to be over.)

Further, after 2010 a new set of science standards (the Next Generation Science Standards, or NGSS) were adopted by 20 states and have influenced standards in 24 other states as well as the District of Columbia. These standards are strongly pro-evolution.

The new survey was of high school teachers, with 2503 in the initial set and a 40% response rate. (The authors discuss the possibility of bias in the sample who answered, but dismiss it for empirical reasons given in the paper.) The questions asked were largely identical to those in the 2007 survey.

I won’t go into a lot of detail about the survey, and will report just a few key results.

The Table below shows both surveys’ data on how many hours were devoted to human evolution and “general evolutionary processes”. In both surveys, only 17% of teachers didn’t cover human evolution, while those not covering general evolutionary processes went up a bit, from 1% to 5%. More important, the mean number of hours devoted to evolution rose substantially: for human evolution from 4.1 to 7.7 hours, and for general evolution from 9.8 to 12.4 hours—a rise of 88% and 48% respectively. That’s a lot more hours about evolution than I got in my high-school biology class, where the topic was left to the end, probably in hopes that we wouldn’t get to it. (I went to high school in Virginia).


Here’s part of Table 2 showing how teachers actually teach evolution—whether they teach it as a broad consensus that it’s a fact.  Again, there is a rise over the survey period in those who do. If you lump “strongly agree” with “agree”, the total goes from 74% of teachers to 79% of teachers, while the “strongly agree” category rose by over 50%, from 30% to 47%.  So there’s been a shift even within the “generally agree” category. Those who disagree and who strongly disagree dropped, with the total of these two positions dropping from 22% to 14%. Again, that’s good news.

Below you can see that the number of hours devoted to creationism or ID dropped, which will really tick off the Discovery Institute. 82% of teachers in the latest survey (as opposed to 75% in 2007) don’t cover any form of creationism, while 13% devote some time to it. However, other questions show that much of the discussion of these creationist views is devoted to showing why they are not a valid scientific alternative to modern evolutionary theory. Because the proportion of teachers giving this negative view of creationism has also increased over time, the figures below are actually an underestimate of the degree to which evolution is taught according to the modern scientific consensus.

Finally, based on teachers’ responses to the questions, the authors divided them into four groups as to how they present evolution to the students. From the paper:

. . . a clearer picture emerges if we summarize the results. To do so, we assigned teachers to four categories based on themes they agreed that they emphasized to their students.Footnote4 The first group are those who reported that they emphasized to their students that evolution is established science: all teachers who said that they “emphasize the broad consensus that evolution is a fact, even as scientists disagree about the specific mechanisms through which evolution occurred” and did not report sending any pro-creationism messages. Exclusively pro-creationist teachers are all who agreed that they emphasized creationism as a “valid scientific alternative” to their students. All other teachers we classified as either “avoiders” (those who agreed with none of the relevant statements) or sending “mixed messages” (those who told us they emphasize both positions).

As you can see from this plot, the green boxes—the proportion of rational teachers who present evolution as settled science—have risen from 51% to 67% in 12 years, while the avoiders, those who send mixed messages, and the creationists have all dropped, though not always significantly so.

There’s a long discussion of why this is happening, though it’s not very conclusive because of the difficulty of parsing out causes in such a sample. The authors attribute it to the adoption of the NGSS, the increasing tendency of older teachers to teach evolution as settled science, and to the  influx of younger teachers who are more prepared to teach evolution as a fact (maybe they read my book!).

Re the latter: it’s palpably clear that not only is America becoming more secular, but also that less religious people are more accepting of evolution. This goes along with the one decades-long trend that we’ve seen in American acceptance of evolution from the frequent Gallup polls surveying American acceptance of evolution: the rise of those who accept evolution as a purely naturalistic proposition, not driven by God and not the result of a creation event.  To wit, follow the dark green line (click on screenshot to see the poll):

Take that, Discovery Institute! (No worries, they’ll find a way to dismiss these data.)

h/t: Laura Helmuth, who tweeted about the results, calling them to my attention.

Science educator invites questions about evolution from public by walking around with a sandwich board

February 20, 2020 • 12:15 pm

I have to admit that Maggie Ryan Sandford is much braver than I. In the article below from Nature, and in the short video embedded in it (I put it below), she dons a sandwich board that says, “Ask me anything about evolution,” and parades around the Minnesota State Fair.  (Sanford is identified as “a science communicator and author of the 2019 book Consider the Platypus: Evolution through Biology’s Most Baffling Beasts.”)

  You can read her short piece by clicking on the screenshot below:

Clearly her object was to engage people in a discussion about evolution, and the implicit aim was to convince them that evolution is true. In the process, she says she learned some lessons about how to change people’s minds (sadly, that aim isn’t spelled out clearly.)

It didn’t hurt that Sanford answered “yes” when people asked her, “Do you believe in God?”, as a “no” would certainly turn away people bent on having a good time at the fair. But here are the lessons she said she learned from this perambulation:

. . . as a science communicator and former education researcher, I knew that, in matters of deep personal belief, facts matter less than feelings. The need to identify whom you’re dealing with is a natural human instinct. Answering was the only way to unlock the rest of the conversation. So I simply let people know I was a big fan of the globe and everything on it, and that I’d written a book about animals that I hoped people would find inviting.

And so to her three lessons:

Lesson 1: Don’t argue with beliefs. People tend to incorporate facts that align with their belief systems.

No problem. I just had to find topics that made sense to all of us — pro-and anti-evolution alike. Dogs or livestock breeding, for example. Half the folks within a 30-metre radius were there to showcase their carefully bred cows, horses and chickens. Open-faced and genuine, I invited them to school me on the areas of their expertise. Which, it turns out, is evolution.

I agree. If you’re there to change people’s minds, don’t mix anti-theism with pro-evolutionism. And if you can change the mind of a cow breeder by telling her that she’s actually practicing evolution by artificial selection, so much the better; but Sanford doesn’t say that she changed anybody’s mind!

Lesson 2: Listen. The most challenging group of the day consisted of two men and a woman in their late twenties. The men were just looking for a fight. Telling me why I was wrong was, I supposed, a way of asking me about evolution. I asked them to elaborate, to tell me why it was that they found evolution hard to swallow. This led to their female companion insisting: “She listened to you. Now you listen to her.” In the end, one man explained my points to the other. “She’s saying evolution is mutations in our DNA,” he said, forcing his companion to let him finish. “I’m just saying, I get her side.”

Agreed again. You can’t get in people’s face and hector them about evolution: you’d be acting like a Darwinian Elizabeth Warren. And if people are open-minded, then of course you should hear them out and answer them patiently, especially if you’re wearing a sandwich board that invites a give-and-take. But again, was anybody’s mind changed?

Lesson 3: Learn what people really think. Almost everyone — secular and religious — had misconceptions about evolution. Advocates of evolution often hadn’t learnt that evolution can now be tracked in genomes, not just fossils, and that humans are related to all living things, and that we didn’t come from apes because we are apes (keep in mind, ‘ape’ is a word that humans made up).

It’s extremely useful to learn what the most common misconceptions are about evolution (e.g., “in evolution, everything happens by accident”). This way you can prepare yourself for what you’re about to encounter, and have some ready answers.

Finally, Sandford avers that the ability to relate to another person as a fellow human is key in helping them accept evolution:

Lay people are more likely to trust and engage with science when they learn that researchers are human beings, fallible and conflicted. Yet somehow it seems hard for many in the scientific community to show those qualities to others. A common concern is that, in the anti-evolution, anti-science debate, any whiff of disagreement or uncertainty spells doom for scientific arguments.

When I began this ‘experiment’, my hypothesis was that a willingness to show vulnerability — to show that we science folks are willing to listen and receive criticism — boosts credibility, not the opposite. I think my experience supports that. When feelings speak louder than facts, appealing to feelings can actually work in favour of science.

I’m not sure what it means to “receive criticism” when you have the truth on your side, as Sandford does, but perhaps she means only that you should listen to people’s beefs about evolution.

But, as I’ve said several times, Sandford doesn’t mention whether she actually changed any minds—not one. What she did seem to learn is that religion is the biggest block towards accepting evolution:

But the misconceptions of religiously inclined folks often had greater personal significance. Listening to them, it became clear that they considered evolution an attack on all they held dear. Several asked me about a narrative they’d heard somewhere about how “life began when water was dripping on a rock”. Clearly, they were worried that such a narrative undercut the idea that humans were created in the image of God.

And indeed, you don’t even have to be especially religious to consider evolution an attack on your worldview—although it helps. Evolution undermines human exceptionalism and our self-image in many ways. In the book below, which I recommend, Steve Stewart-Williams goes through all of these ways (click on screenshot to go to the Amazon site):

And here are two of the slides I use when explaining why Americans are scared of evolution; many of the points are from Stewart-Williams’s book (and I credit him when I show these slides). The red bits are implications that I consider especially important in turning people off evoution:

In general, while teaching facts about evolution does work, as I know from the email responses I got to the book Why Evolution is True, American remains obdurately anti-evolution, with only 22% of us accepting naturalistic evolution for humans compared to 40% being young-earth creationists and 33% theistic evolutionists (those who think God intervenes in the process, especially in the origins of humans). In other words, 73% of us have a supernaturalistic view of evolution—more than three times the frequency of those who accept “Darwinian” naturalistic evolution as it’s taught in biology class.

In the end, the vast majority of opposition to evolution comes from religion. The more religious the country, the less acceptance of evolution. Religion immunizes people, at a every young age, against evolution, for they get their faith before they learn about biology. As I always say, if I could do just one thing to increase the acceptance of evolution in America, it would be “make religion vanish.”

That is a hard job, and will take decades or even centuries. And it’s why I wear two hats, one as an evolution teacher and promoter, and the other as an anti-theist. I’m not sure that Maggie Sandford’s strategy works, as she seems to go light on the facts and completely avoids criticism of faith. It’s no surprise that she doesn’t boast about her victories at the Minnesota State Fair!

But I’d be churlish to tell her to lay off, because she may well be planting seeds of doubt in people—seeds that may sprout only much later. So Ceiling Cat bless her for having the courage to parade her views in public and invite criticism. I do wish her success.

Here’s the video:

h/t: Dom

Early feminist education

January 17, 2020 • 5:24 pm

In this world of patriarchy, where structural sexism is ubiquitous, it’s important to educate future women in the nature of their oppression. Here I am teaching little Selma, granddaughter of my friends, about the great women of history, emphasizing that women can be whatever they want.

I also taught her about penguins, which seemed to fascinate her. After all, it’s never too early to learn about biology:

You go, girl!

(Photos by Tim Groves)

This Sunday: Cosmic volcanoes, future humans and Neanderthals!

November 5, 2019 • 5:03 am

by Matthew Cobb

This post is an unashamed plug/PSA.  RATIO is a regular popular science festival held in Sofia, Bulgaria. I have spoken there a couple of times, as has Jerry. The event attracts hundreds of attendees, and is a major event. Now they are opening their doors to everyone, all over the planet – you can live-stream the upcoming talks, on Sunday 10 November, for JUST FIVE EUROS. (That’s basically five dollars.) Full sign-up details here. As well as the talks there will be a panel discussion. Here’s an example from 2018, including the fabulous Erica McAlister, keeper of flies at the London Natural History Museum.

There are three talks this Sunday:

Robin Andrews: From Alien Volcanoes To Terminator Asteroids: The Solar System Is A Freak Show

Our solar system is stranger than you think. There are earthquakes that can last for nine days without anyone noticing them on Earth. On Saturn, it rains diamonds. On a moon of Jupiter, thanks to its awkward orbital ballet, the rock moves in the way that tides move on Earth, which fuels volcanic eruptions that outshine entire worlds. On Titan, the atmosphere is so soupy that if you flapped your arms, you could fly around…

Martin Moder: Human Оptimization

The world’s first designer babies premiered about a year ago. Time to consider, whether we’re even capable of defining what “optimization” should mean.

Which of our traits are affected by genetics? How far are we from influencing their biological foundation? Could we enhancing general intelligence without tedious studying to finally become less stupid?

Jonathan Pettitt: May Contain Neanderthal

Your DNA is not your destiny, but it is your ancestry; or at least it’s a record of it. Genetics has given us extraordinary insights into our collective human past, showing the patterns of migrations and unions that have shaped our individual genetic inheritances.Investigations into human evolutionary genetics have revealed some deeply non-intuitive findings, which have implications for both the present and future оf human biology and medicine.

I know that PCC(E) would want to join me in encouraging you to sign up. RATIO is a brilliant initiative, and the people behind it – mainly volunteers – have slowly created a really important piece of science communication in eastern Europe. They deserve all our support!

Secularism on the rise: new Gallup poll shows that 40% of Americans are young-earth creationists, 33% are theistic evolutionists, and 22% are naturalistic evolutionists

July 27, 2019 • 11:00 am

Over at a Gallup poll site, you can see the headline below reporting the newest iteration of Gallup’s sporadic—now yearly or biennially—survey of American belief in creationism. (It’s really belief in human evolution, so be aware that there are many who think that while other species evolved à la Darwin, humans alone required divine intervention. Do remember that Tennessee’s Butler Act, whose violation led to the trial of John Scopes in 1925, forbad the teaching of human evolution, not evolution in general. )

That headline seems scary, no? In fact, if you read here regularly, this is pretty close to long-term estimates of Biblical young-earth creationists gathered by Gallup since 1982 (the percentage has varied between a low of 38% two years ago and a high 47% in 1993). Here are the data taken since the first survey in 1982.

But in fact the headline is a big underestimate. In fact, 73% of Americans believe in creationism—if you count those who think that God guided an evolutionary process leading to the evolution of humans “over millions of years from less advanced forms of life”.  If God is guiding the process, then there has to be some divine, teleological intervention in evolution, just as Intelligent Design advocates propose. This could happen in several ways. God could, as Michael Behe apparently believes, create the right mutations at the right time, circumventing the naturalistic “random” mutations that most biologists accept but that, says Behe, can’t produce complex adaptations. Or there could be differential reproduction or extinction mandated by some undetected interventions of God. Maybe God tweaked the reproductive potential of those members of Homo who had bigger brains.

So the proportion of Americans who accept some divine hand in evolution is really 73%, and what is divine intervention except a form of creationism? Granted, it works hand in hand with evolution, but it’s a non-naturalistic theory. Thus, by saying that the figures are 40%, Gallup is underestimating the real figure by 45%.  On average, only 22% of Americans—a bit more than one in five—accept a purely naturalistic view of human evolution.

Although Gallup says that the figures for creationists and theistic evolutionists have held pretty steady, the long term-trend is really down a bit (their sum was 82% in 1982 and is now 73%).

One trend that is evident is the slow but ineluctable rise of naturalistic evolutionists, which has more than doubled (9%-22%) over the last 37 years. I’m betting this isn’t a statistical fluke, but a real increase of American acceptance of evolution.

Why is this happening? My theory, which is mine (but also other people’s), doesn’t require any perspicacity: it’s almost surely due to the increasing secularization of America. “Nones”—those who aren’t affiliated with a church—are now nearly a quarter of the American population, and about a third of young people. Granted, many of those are still deists, or even theists, and many are spiritual, but there’s no doubt that the unaffiliated are more willing to accept naturalistic evolution. If you don’t believe in a theistic God, then what reason do you have to oppose evolution?

You can see that in the demographic, educational, and religious breakdown given by Gallup:

These are the usual results: the lower the index of a person’s religiosity, the more likely they are to accept evolution. Young-earth creationism is higher among Protestants than Catholics (though more of the latter accept theistic evolution), and the “nones” are rife with evolutionists: 59% of them accept unguided, naturalistic evolution.

Do note that although the Catholic Church officially accepts evolution, 34% of them remain young-earth creationists, bucking their church’s dogma, while only 18% of them are naturalistic evolutionists. (The Church does broach some supernatural views of evolution, including the important tenet that all living humans are the lineal descendants of one pair of people: Adam and Eve.)

Finally, having a college degree strongly reduces your chances (by more than 50%) of accepting young-earth creationism of humans (though, curiously, it increases the probability of accepting theistic evolution), but that college degree also doubles your likelihood of accepting naturalistic evolution of humans.

The upshot? Creationism—both young-earth and “goddy interventionist” forms—is still the dominant American view of how humans came to be. But, slowly and surely, those who accept evolution in the same way scientists accept it are growing. Why, in 80 years, if the trend continues, nearly half of Americans will accept evolution! None of us will be around to see that, and our species might not even be around. But at least Americans are growing saner.

I’d love for some reporter to ask Trump, as well as the Democratic candidates for President, if they accept naturalistic evolution. I don’t think anyone has ever asked Trump about that.

Here, for those interested in such things, are the methods Gallup used to get these figures. And remember again that the data are about human evolution. If you left out humans in the questions, you’d see a lot fewer creationists, at least of the young-earth, Biblical type.




h/t: Barry

Human Phylogeography: The lessons learned, 1

June 4, 2019 • 9:10 am

by Greg Mayer

UPDATE. A couple of readers have drawn attention to the website, gcbias, of Graham Coop, a population geneticist at UC Davis. He has excellent discussions, with nice graphics, of issues in genetic genealogy, including calculation of the number of “genetic units” in particular generations. As an example, 7 generations back you have 256 ancestors, but only 286 genetic units produced by recombination, so although, on average, you will have a chunk from each of those 256, it is entirely plausible to have zero (since inheritance is stochastic). It’s well worth browsing, and this and this are good places to start. (Thanks to rich lawler and S. Joshua Swamidass for the pointers.)

In February, I posted the syllabus for a seminar class entitled “Human Phylogeography” that I was teaching with my colleague Dave Rogers. The seminar was based primarily on a close reading of David Reich’s (2018) Who We Are and How We Got Here (published by OUP in the UK). Well, the class has concluded now, and so I thought I’d report back on what happened.

First, I’d like to say that the class was a success. We had 16 students, double the most I’ve ever had in a number of similar seminar courses over the years, and the students were very successful in engaging with the subject in both written and oral contributions to the class. One of the students was a history major, and towards the end of the semester a colleague in computer science mentioned that, quite coincidentally, he was reading the book, so he joined the class for the last few meetings. In many ways, it was what college is supposed to be like (though too often isn’t). I hope the students learned a lot. I did, and here is the first of the three most striking things I learned.

1. Recombination is a lot rarer than you think.

If you think back to the last time you studied genetics, you’ll recall the phenomenon of recombination, one aspect of which is crossing over. Crossing over occurs during meiosis. Chromosomes come in homologous pairs (23 pairs in humans, for 46 total), and in meiosis the homologues can exchange pieces with one another. The chromosomes physically touch and cross one another, which is observable under the microscope, and are called, appropriately enough, chiasmata (chiasma, sing.)

Image result for crossing over meiosis
From BioNinja,

Recombination is important for a variety of reasons (for one, it increases genetic variability), but for our current purposes its importance is that it breaks up the nuclear genome from 23 genetic units into more, and smaller, units (as opposed to the mitochondrial genome, which has a number of genes, but all are inherited as a single genetic unit, since there is no recombination in mitochondria). In humans, it turns out, there are only 1-2 crossovers per chromosome per generation (1.2 per chromosome in fathers, 1.8 in mothers).

Now, I’d always thought that crossing over occurred frequently enough that we could think of the genome as essentially infinitely divisible. (There are 3 billion base pairs in the human genome, so, in the limit, there would be 3 billion genetic units, so not quite infinite!) But, it turns out that crossovers occur sufficiently infrequently that there is an appreciable chance that, if you go enough generations back, you share NO genes with your ancestor. This is because the number of ancestors goes up fast (2, 4, 8, 16, 32, 64, 128, 256, etc.), but the breaking up of the genome into smaller units by crossing over isn’t fast enough to ensure that the probability of sharing nothing is near zero.

Here’s a figure from Reich’s book showing how blocks of genes are broken up by recombination.

From Reich, 2018.

You start with an entirely Neanderthal chromosome (dark), which enters the anatomically modern human population by hybridization. A few generations later, the Neanderthal chromosome has been broken up, but it still occurs as largish blocks amongst the anatomically modern sections (gray). Still later, the blocks are smaller and fewer. (We’re assuming continued backcrossing into the anatomically modern population, so the % Neanderthal decreases; there could also be selection causing changes in the frequency of Neanderthal alleles). Finally, a present day individual has his Neanderthal DNA broken up into even smaller bits.

Here’s a figure from a talk by Svante Pääbo, showing in the top row for each chromosome (there are 22 listed, from 1-22) the entire genome of “Oase Boy” from 40K years ago in Romania. The green lines are Neanderthal sites in his genome. The five rows below Oase Boy are five modern human individuals; the colored lines are their “Neanderthal bits”. Note that for each chromosome, Oase boy has the biggest block of Neanderthal genes (green fluorescece):

From Pääbo , 2018. (Click to enlarge.)

Because of the age of the Oase sample, some of the black lines are missing data, and so Pääbo infers that there are seven large continuous blocks of Neanderthal genes (yellow bars above the Oase Boy line). Note that the modern individuals have less Neanderthal DNA, and it is not in large blocks.

Because the size of the blocks breaks up in a statistically predictable fashion, you can get a “recombination clock“, so that based on the size of the blocks you can estimate how many generations ago the hybridization occurred. For Oase Boy, Pääbo estimated that his Neanderthal ancestor occurred 4-6 generations back (his great great, or great great great, or great great great great grandfather).

From Pääbo , 2018, showing Oase’s Neanderthal ancestor (red) in the 5th generation (it could also be in the 4th or 6th).

Because the placement and frequency of crossing over is stochastic (random), the situation must be statistically modeled to derive sound estimates, and there will be a range of plausible estimates. And, since some of the fossils are well dated by other means, we can also estimate the long term human generation time, as was done by Priya Moorjani and her colleagues: it’s 26-30 years.

So, the low rate of recombination allows us to construct a “recombination clock”, and to estimate generation times. This is great stuff!

It also solved for me what was a puzzle. You may recall that last year Elizabeth Warren released the results of DNA tests showing that she had American Indian ancestry several generations back. This essentially confirmed what her family’s oral history said. The amount of her Indian ancestry was small (less than 1%), and a range of generations (6-10) was provided by the analysis (as was done by Pääbo for Oase Boy).

Now, there are a number of ways which these ancestry tests can be criticized, one of the most difficult for them being that there are very few North American Indian genotypes in the database used, and thus “American Indian” relationship is indicated by relationship to Central and South American Indians. Some critics of Warren, however, made erroneous criticisms. She did not contend, as some accused her of, of saying the results showed she was Cherokee—with few if any Cherokee in the database, the ancestry tests could not determine this. (And tribal membership is a legal matter, anyway, not directly dependent on genetic similarity.)

But some critics said that the data were consistent with her having no Indian ancestry at all. I wondered how they could say that– there are 3 billion bp, and 1 % of that is still a very large number. But now I realize my error. There are very many fewer genetic units– more than 23, but a lot less than 3 billion!– due to low rates of recombination. And, because of this, if you go back several generations, there is an appreciable probability of sharing no DNA with an indubitable ancestor. I now believe the critics must have looked at the latter fact, and realized Warren may not have DNA from all of her ancestors, and thus suggested she may have no Indian ancestry. But their error is that in saying she may lack DNA from an ancestor, say, 8 generations back, they are invoking an a priori probability. But in Warren’s case, her DNA was examined, and showed that she did have Indian ancestry.

Gravel, S. 2012. Population genetic models of local ancestry. Genetics 191:607-619. pdf

Ho, S. Y., Chen, A. X., Lins, L. S., Duchêne, D. A., & Lo, N. 2016. The genome as an evolutionary timepiece. Genome Biology and Evolution 8: 3006–3010. pdf

Huff, C.D. et mult. 2011. Maximum-likelihood estimation of recent shared ancestry (ERSA). Genome Research 21:768-774. pdf

Moorjani P, Sankararaman S, Fu Q, Przeworski M, Patterson N, Reich D. 2016. A genetic method for dating ancient genomes provides a direct estimate of human generation interval in the last 45,000 years. Proceedings of the National Academy of Sciences USA 113:5652-7. pdf

Pääbo, Svante. 3 October 2018. A Neanderthal Perspective on Human Origins. (video: embedded below)

Reich, D. 2018. Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past. Pantheon, New York.

National Review: Conservatives should accept evolution

May 15, 2019 • 1:00 pm

Both the Left and Right have their issues with evolution. On the Right, many are evangelical Christians and reject evolution on religious grounds. Even Orthodox Jews like Ben Shapiro have found themselves flirting with Intelligent Design, and when I saw Shapiro implicitly attacking modern evolutionary biology I gave up all hope for him. The voting base for the Right may be fine with those who attack or deny evolution, but in the long run you’re going to look pretty stupid if you reject it. (It’s curious that I know nothing about Trump’s views on the issue.)

The Left, too, while accepting Darwinian evolution in general, has problems with evolutionary psychology—not that the discipline is perfect. But wholesale rejection of it, by those like P. Z. Myers, is intellectually dishonest and ideologically driven. Many also imply that evolution tells us that there is a spectrum of not just gender, but of sex itself, so that sex is not “binary”.  In fact, three organismal biology societies, including the Society for the Study of Evolution (of which I was once President), issued a statement saying that “sex is a continuum” which is infuriatingly wrong. In our species, and many others, evolution has in fact favored a binary: male and female.

Denial or rejection of evolution, then, is based on ideology: largely religious on the Right and Blank Slate-ism on the Left.

It’s refreshing, then, to see an article in National Review, a conservative journal, arguing that a.) evolution is true and b.) conservatives shouldn’t be afraid of it. The article is below (click on screenshot); it’s by Razib Khan, a geneticist and science writer. He’s been criticized for writing for questionable publications that purvey racism and bigotry, and on that grounds the New York Times let him go as a temporary columnist. He surely must be a conservative; in fact, he identifies himself as one in the first sentence.

But whatever his past, the piece in the National Review isn’t half bad (click on screenshot):

He does point out the forms of evolution denialism I highlighted above, but of course his article is motivated by conservatives’ rejection of evolution, and to that end he takes out after Michael Behe, whose Intelligent Design views are much admired by conservatives like Shapiro. In general, though, Khan highlights how evolution has made testable predictions, and how much we know about these days. In short, he tells conservatives that it’s true, and to stop fighting it.

But I have mixed feelings about stuff like this:

But evolutionary biology is nothing for conservatives to fear, because it is one of the crowning achievements of modern Western civilization. It should be viewed not as an acid gnawing at the bones of civilization, but as a jewel. The science built upon the rock of Charles Darwin’s ideas is a reflection of Western modernity’s commitment to truth as a fundamental value. And many Christians well-versed in evolutionary science find it entirely compatible with their religious beliefs.

Further, while evolutionary biology does not tell us what is good, the truth of the world around us can inform our efforts to seek the good — and in this sense, the political implications of evolutionary biology do not favor the Left. Today many on the Left reject the very idea of human nature, to the point of effectively being evolution deniers themselves. They assert that society and values can be restructured at will. That male and female are categories of the mind, rather than of nature. In rejecting evolution, a conservative gives up the most powerful rejoinder to these claims.

Those who reject human nature on the Left are not mainstream Leftists, but extremist Leftists, and the data show that many more people on the Left accept evolution in general, including human evolution, than those on the Right. But it’s wrong to imply that the Left consists of wholesale deniers of evolution. True, Blank Slaters do reject mainstream science (and not just evolution—also evidence that male and females have different brains and show different innate preferences), and that’s to their discredit.

Here are data from a 2013 Pew poll showing that the problem is greater on the Right than on the Left:

Khan also errs, I think, when trying to show that evolution is compatible with religion. He uses the old trope that “some scientists were religious, ergo harmony”:

But what about the metaphysical implications? Richard Dawkins would have you believe that evolutionary biology is fundamentally atheistic. But he is one voice. There are in fact evolutionary biologists who are religious, including Evangelical Protestants. The most influential evolutionary biologist of the first half the 20th century, R. A. Fisher, was an Anglican and a political conservative. The existence of people who are Christians and evolutionary biologists shows that there is a wide range of opinions on how evolutionary biology relates to religious faith.

True, but newer data also show that religious people are far less accepting of evolution than nonreligious people, and of course the large majority of scientists in elite universities are out-and-out atheists. Here are more data from that Pew poll:

Note that the biggest acceptors of evolution are “unaffiliated” people and white mainline Protestants, while the more conservative religious show less acceptance—especially white evangelical Protestants.

And for good reason: evolution in fact does fly in the face of many religious beliefs—not just in its flat denial of Biblical claims like the Creation and of Adam and Eve as the progenitors of all of us (I’m looking at you, Vatican), but in other ways too. Here are two slides I use in my talks about the incompatibility of science and faith (many of these points are taken from Steve Stewart-Williams’s excellent book, Darwin, God and The Meaning of Life: How Evolutionary Theory Undermines Everything You Thought You Knew):

The points in red are the ones I consider most important in promoting rejection of evolution by religious people. Ergo, conservatives are still going to have trouble accepting evolution insofar as they need to comport it with their faith. Nevertheless, Khan is absolutely right when he says this:

But looking forward, the energies of the Right are not most fruitfully spent on debating descent with modification and the common origin of life.


Teaching Evolution: Sewall Wright: Evolution in space

March 9, 2019 • 10:30 am

by Greg Mayer

Our next installment of Teaching Evolution for this spring concerns Sewall Wright. His contributions were wide-ranging, but he is most noted for his integration of population structure (population size, migration) and selection into what he called the “shifting balance” theory. In this theory, genetic drift, migration, and selection interact to produce what he saw as the most favorable conditions for evolutionary advance. The reading is a brief precis of his much longer 1931 paper in Genetics, but in many ways was more influential, as it exposed a wider audience to his ideas. Modern appreciations of the shifting balance theory are given by Nick Barton (2016) and Norm Johnson (2008).

Sewall Wright, with guinea pig.

Sewall Wright (1889-1988) was, along with R.A. Fisher and J.B.S. Haldane, one of the founders of theoretical population genetics, which synthesized Mendelian inheritance with Darwinian natural selection, thus laying the foundations of modern evolutionary biology. His classic paper “Evolution in Mendelian Populations” (Genetics, 1931) laid out his synthesis, and led to his election to the National Academy of Sciences while still a young man. Like Darwin, Wright studied carefully the work of animal breeders, and this strongly influenced his ideas on evolution, which he called the “shifting balance” theory. Although sometimes caricatured as a theory emphasizing random genetic drift, Wright stressed the importance of the interaction of drift, selection, and migration in adaptive evolution. Wright strongly influenced Dobzhansky, and he coauthored five papers in the latter’s “Genetics of Natural Populations” series. Beginning with his graduate studies at Harvard, Wright’s organism of choice for genetic studies throughout his career, which ended with a very productive 33 year retirement at the University of Wisconsin, was the guinea pig (note what is in his left hand in the photo). He is author of the monumental four volume Evolution and the Genetics of Populations (1968-1978). William Provine has edited a collection of Wright’s most important papers, Evolution: Selected Papers (1986), and written an insightful and analytic biography, Sewall Wright and Evolutionary Biology (1986).


Wright, S. 1932. The role of mutation, inbreeding, crossbreeding, and selection in evolution. Proceedings of the Sixth International Congress of Genetics 1:356-366.

Study Questions:

1. In this paper, Wright introduces the idea of a fitness surface or adaptive ‘landscape’ (see esp. Fig. 2). What do the x and y axes (the two dimensions of the ‘map’ on the paper) represent? What does the ‘altitude’ of a point on the landscape represent? What does a peak in the landscape represent? What does a valley in the landscape represent?

2. In one sentence in the first half of the paper, Wright succinctly states the Hardy-Weinberg equilibrium for allele frequencies, and its cause. Find and quote the sentence. Show that Wright understands the H-W principle.

3. Why is it difficult for a species to evolve across a valley from one peak to another if selection is the only evolutionary force? How does this lead Wright to argue for the importance of drift (inbreeding) and migration (crossbreeding), as well as selection, in allowing species to reach the highest adaptive peaks?


Jerry addendum:  While Wright’s theory was influential, and was incorporated by Theodosius Dobzhansky into his view of the Modern Evolutionary Synthesis (see his book Genetics and the Origin of Species), I find the theory deeply flawed. With two colleagues, Nick Barton and Michael Turelli, I wrote a long critique of that theory in 1997. Our paper was in turn criticized in two papers, one by Mike Wade and Charles Goodnight, and the other by Steven Peck et al.  We then rebutted these papers in another Evolution paper in 2000. All four references and links are below.

In my biased estimation, our critique did stem the tide of enthusiasm for Wright’s theory; in fact, Wright’s colleague James Crow at Madison said that our paper prompted him to stop accepting that theory. I’m not sure whether Greg mentions the critiques and attempted rebuttals in his lecture, but I’m putting them here for readers.

Coyne, J. A., N. H. Barton, and M. Turelli.  1997.  A critique of Sewall Wright’s shifting balance theory of evolution.  Evolution 51:643-671.

Wade, M. and C. J. Goodnight. 1998. The theories of Fisher and Wright in the context of metapopulations: when nature does many small experiments. Evolution 52:1537–1553.

Peck, S. L., S. P. Ellner, and F. Gould. 1998. A spatially explicit stochastic model demonstrates the feasibility of Wright’s shifting balance theory. Evolution 52:1834–1839.

Coyne, J. A., M. Turelli, and N. H. Barton.  2000.  Is Wright’s shifting balance process important in evolution? Evolution 54: 306-317.