Sunday, December 08, 2013

Steven Pinker defends "neo-Darwinism," whatever that is

Jerry Coyne posted a couple of tweets (see below) from Steven Pinker (photo) at Dawkins responds to Dobbs.

We shouldn't be surprised at the first one since Pinker is an evolutionary psychologist with a strong tendency to adaptationism. I don't know exactly what he means by "neo-Darwinism" (does he?) but I strongly suspect that it's very much like Darwinism. I'd love to know whether he thinks Neutral Theory and random genetic drift have been successful challenges to neo-Darwinism. If not, then it must mean that neo-Darwinism has incorporated those views. In that case, neo-Darwinism must have begun in the 1970s and somebody picked a very bad name for this view of evolutionary theory.

I think it's more likely that Pinker is just not thinking about Neutral Theory and random genetic drift when he says that challenges to neo-Darwinism have all failed to hold water.

The second tweet means that molecular biologists never knew about tRNA genes or ribosomal RNA genes or the genes for other RNAs that have won Nobel Prizes. I find this very surprising. It's true that some biochemists and molecular biologists are a bit behind in their field but I don't think it's fair to say that "molecular biologists" (i.e. the knowledgeable experts in the field) re-defined the word "gene" in that way.



25 comments:

  1. I think I can interpret what the first tweet refers to: the Modern Evolutionary Synthesis has been challenged by people who invoke epigenetics, phenomena of evo-devo, punctuationism, and a variety of other existent and nonexistent phenomena. the Synthesis has survived all these. It has turned out that some of these phenomena either do not exist (as in the case of neo-Lamarckian mechanisms). Other such as epigenetic mechanisms have little long-term effect. The rest can be considered to be examples of the workings of the mechanisms of mutation and selection, as in the case of evo-devo phenomena.

    Similarly the Synthesis incorporated neutral mutation and nearly-neutral mutation. As for the word "neo-Darwinian", it is gradually falling into disuse. This is partly for an historical reason: it turns out that in the late 1800s there were a group of scientists influenced by Darwin who championed the mechanism of natural selection when many other scientists were abandoning it, and they were referred to at the time as neo-Darwinians.

    Pinker and Coyne are using "neo-Darwinian" simply as a synonym for the Modern Evolutionary Synthesis.

    "Neo-Darwinian" is also sometimes taken as a modern-day name for panselectionist. That is what you are doing. Panselectionism has lost ground, but not the Modern Evolutionary Synthesis.

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    1. It would greatly help if people start using consistent terms the meaning of which everyone can agree on. I have seen people using the Modern Evolutionary Synthesis as synonymous with panselectionism too. This is not entirely without a reason if I understand what people refer to when they talk about its "hardening" (with the caveat that I was not even born when those debates were happening) but it is also entirely true that it incorporated neutral processes with ease. Which makes for a total mess when it comes to knowing who is attacking/holding what positions.

      P.S. Some examples of neo-Lamarackian mechanisms are difficult to argue against IMO, for examples CRISPRs. Heritable genetic changes, directly caused by the environment. It's true that they have little long-term consequence though, as they seem to be limited to pathogen-host arm races.

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    2. Larry, I think it was Darwin who first recognized the possibility of evolution by genetic drift. I took the following quote from “On the Origin of Species (1859, p. 81):
      “This preservation of favourable variations and the rejection of injurious variations, I call Natural Selection. Variations neither useful nor injurious would not be affected by natural selection, and would be left a fluctuating element, as perhaps we see in the species called polymorphic.”

      There are two things to note. First, Darwin has natural selection acting primarily on variation (phenotype) and not directly on the underlying genetic causes. This is the definition in recent textbooks by Freeman and Herron (Evolutionary Analysis), Stearns and Hoekstra (Evolution), and Futuyma (Evolution, in part). Darwin perceived natural selection (and sexual selection) as ecological (and social) processes. This definition has no effect on the practice of genetics, although it might diminish self-esteem.

      Second, it looks like Darwin has priority with respect to evolution by genetic drift (defined as random changes in frequency of unselected hereditary elements). I hope in the future you will honor Darwin as being the primary source of the idea of drift.

      Although Darwin could not have understood the real dimension of genetic drift, this statement shows that he saw nothing amiss with neutral evolution as complementary to adaptation. Darwin, I think, did a good job with the limited information he had available. The point is that adaptive evolution and drift both exist in classic Darwinism, and nothing in the basic story changed much with Mendelian genetics.

      Cheers

      P.S., Re Felsenstein’s comment: I claim to be a hyper-adapationist/selectionist only in the sense that I object to much of Stephen J. Gould's tomfoolery.

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    3. It's long been noted that Darwin wasn't exactly a "Darwinian" in that he never claimed that natural selection was *the* answer, but just part of it. That's pretty typical of any founder of a school of thought.

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    4. I'm going to disagree with W. Benson: I don't think Darwin was talking about genetic drift. His phrase:

      "... would be left a fluctuating element, as perhaps we see in the species called polymorphic"

      I am pretty sure means left with both types present. "Fluctuating" in his case means, I think, varying. It does not mean changing proportions through time. The random variation of proportions brought about by random births and deaths in finite populations is, I think, far from this meaning.

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    5. "It would greatly help if people start using consistent terms the meaning of which everyone can agree on."

      If only.

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    6. I don't think Darwin was talking about genetic drift.

      It does seem that he missed the fact that non-selected variation would still lead to fixation. This took a surprising amount of time to establish.

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    7. It took quite a lot of time do develop a mathematical model of Brownian motions, too. People apparently tend to imagine that random walks are fluctuations about a point of equilibrium, with deviations cancelling each other in the long run. It only goes to show that human intuitions concerning such processes are completely unreliable.

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  3. It's tough to know what Pinker is precisely referring to with second tweet (and such is the curse of tweeting). Is he referring to fact that the definition of a gene should also include non-coding regulatory regions or that not all genes code for proteins?

    In any case as has been pointed out on this blog multiple times, the existence of functionally important DNA that codes not for protein or even RNA is of course not new to molecular biologists (who are the ones after all who discovered these elements) and furthermore should not be beyond the grasp of journalists who feel qualified to write about genetics.

    At the same time it should be recognized that the close concept between gene and protein stems from two conditions: first, most regions of DNA that we call genes in fact do code for proteins (rather than functional RNAs) and second, deducing both the theoretical and mechanistic relationship between the nucleotide sequence in DNA and amino acid sequence in proteins represents one of the most monumental accomplishments in all of science (in my opinion).

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    1. I cited Pinker's second tweet in my "Genes are not sections of nucleic-acid" article. For most of the last century the term "gene" referred to the heritable basis of traits - not to nucleic acid - which hadn't even been discovered at that stage.

      That usage of the term "gene" was very sensible from an evolutionary perspective - in a way that the molecular biology definition of a "gene" is not.

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    2. I've never bought the idea that somehow actually understanding the physical or chemical basis of something is "redefining" it. Do chemists complain that physicists "redefined" the atom by learning that it wasn't a mere abstraction representing the smallest amount of an element but a real physical thing that actually had smaller parts of its own?

      The classical atom never really existed outside the human mind. It's the same thing with the classical genetic idea of genes. Areas of the genome that encode transcripts exist and are what genes are. The gene as a magical abstraction that somehow encodes a "trait" doesn't exist.

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    3. Tim,
      A gene is what it is, and furthermore, does what it does, and what it usually does is act as a template for the synthesis of an RNA molecule, which for most genes is the code for a specific sequence of amino acids with functional importance. As Jonathan implied above, a deeper understanding of the molecular basis of genetics cannot possibly diminish its usefulness or relevance in any topic.

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    4. I think you folk must be misreading my comment. It wasn't *understaning* genes that was the problem. It was *redefining* the term. Before mid-century, "genes" referred to the heritable basis of traits. After mid-century, for many, "genes" referred to heritable traits encoded in nucleic acids. That narrower meaning might be OK for biochemists, but it sucks for evolutionists - since it leaves out cultural and environmental sources of heritable information. The result has been an epic-scale popular misunderstanding of genetics and evolution. If Semon's "mnemes" had taken off - instead of "genes" - we wouldn't be in this mess.

      The earlier concept was not a "magical abstraction". Piece of heritable information is a basic concept in genetics/evolution - far more basic and important than "nucleic acid fragment" - which is one instantiation of it, among many.

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  4. I'm pretty sure that Pinker's first tweet means nothing, including genetic drift and neutral mutations, has successfully challenged natural selection as, to a first approximation, the only factor in evolution. And I'm pretty sure that Coyne is pleased to cite Pinker's tweet because he agrees these are merely details that serve only to confuse the lay population.

    And I'm pretty sure that Pinker's second tweet is meant to include all mechanisms in gene expression as "genes" that nature has selected. All forms of epigenesis are the consequence of the selfish gene, which determines everything, even when it doesn't code a protein. And I'm pretty sure that Coyne is pleased with the the tweet because that he agrees. Sure seemed to be one of the main points he made to show Dobbs "mucked" up.

    You've already agreed with Coyne. Why are you taking issue with a couple of tweets?
    Everybody who counts thinks very highly of Pinker and citing a respected authority is always good PR for your cause.

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  5. I don't think highly of Pinker and so don't count !!!
    What is a evolutionary Psychologist ? Is this really a biologist?
    i saw some of his youtube things and he discredited himself to me when he said Jews, like him, were more intelligent then everyone else including my people.!!!
    No excuses this is what he said and he's from Montreal so there you go!
    I question why he is celebrated in the media.
    This is your crowd and not ours.
    You gotta love the hair though!!

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    1. (H)e discredited himself to me when he said Jews, like him, were more intelligent then everyone else including my people.!!!

      To be clear, and leaving aside the issue of whether you are accurately reflecting Pinker's views:

      Are you objecting to his suggestion that intelligence can be correlated with ethnicity? Or are you just hurt by the suggestion that Jews are more intelligent than "your people"?

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    2. DISCREDITED completly I say when someone says intelligence is linked to ones DNA.
      ITS ABSURDITY from the past. I thought we were over this suff. I know we are not but where is the left wing pc police when you need them. Skip that ONE never needs them however WOW.
      Ethnicity, whatever that is, and iNTELLIGENCE.
      how many times have i been banned from forums for the innocent inclusive comment that the most intelligent civilization was created by the evangelical/Puritan English and Scottish people/men!!!
      Just from religious motivation raising the moral and intellectual level of the common man and so the upper classes rise also.
      RACIST/SEXIST/RELIGIOUS BIGOT they cry!!! Zap to my posting rights.
      Yet my conclusion is all about free will.
      then others, including the Jewish ones, start saying look at us AFTER they immigrate to US. lIke everyone else.
      YES one can measure and the measuring was finished centuries ago.
      We all agreed to believe in each other and simply raise up the world.
      This Pinker breaks the contract. Lots of them do. In the english language no less(unless Pinker speaks French Canadian being from Montreal)
      Didn't they cry racist at that DNA guy, not Crick but the other, when he mused about Africa??
      I have no problem with any ideas but a problem with dumb ideas that said by anyone else would be punished.
      OH BROTHER. This is your crew. Not ours !
      Is it me????

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  6. """i saw some of his youtube things and he discredited himself to me when he said Jews, like him, were more intelligent then everyone else including my people.!!!"""

    Do you have any links?

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    1. He's probably talking about this:

      http://www.richarddawkins.net/news_articles/2013/8/10/steven-pinker-jews-genes-and-intelligence

      A shorter, written version here:

      http://pinker.wjh.harvard.edu/articles/media/2006_06_17_thenewrepublic.html

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  7. The problem with Pinker commenting on these issues is that he's not a trained biologist, and is fanatically devoted to biological innatism, which is nearly always used to proclaim the superiority of certain sectors of the population (Pinker's version has Ashkenazi Jews as the 'god-men'). There is no scientifically verifiable evidence for the claim that Askhenazis have an average IQ of 115 or higher (Israeli Ashkhenazim have been tested at around 103), but Pinker persists anyway, as it fits his own personal worldview.

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    1. i have no interest or belief in IQ tests say for a momentary shot of abilities of people in restricted ways.
      I have NO problem with measuring people groups and intelligence but the iNNAte thing is the dumb thing and goes against the reality of identity intelligence.
      all people are born the same and simply its a matter of what one grows up in including segregated identity's.
      jowever pinker loses all credibility when he is asserting genetics after his people immigrated to a superior people.
      i mean that all these peoples proclaim their smartness after moving to the Englishmans homes and gardens.
      after moving to mu y peoples IQ land then they start scoring . nOt before.
      So all these obscure third world peoples, including the east european Jews, come to us, brought up to our truly high levels of intellect, and THEN say they were not always our equals but try to say they are superior.
      Oh brother, Now thats cause and effect.
      There is no difference between Jews, African blacks, Indians, or headhunters of new Guinea.
      They simply were brought uo to the level of the British whitemans intellect just by living with us and no longer with their own people.
      Any other things are due to segregation and so motivations.
      We have always said and the bible says their is no intellectual difference, innately, between human beings. Race/sex/anything.
      humbling but true. We are created in gods image and as smart, almost, as god. just a matter of applying ourselves.
      measuring fine but measure correctly and belueve in mankind.
      Look at Canada. All these peoples come up to our level or almost within a generation. Any lingering is from determined segregation and lack of intermingling in some ways.
      its not intellectually excusable for this Pinker.
      'its really backward and worthless conclusions based on raw common observation.
      Pinker is not a Jew but a Canadian from montreal of jewish biological ancestry. he has no choice. he is just another Englishman and not some peasant from some village in russia.
      its an absurdity of investigation.
      Yes hes a evolutionist but even they can do better then this.
      I bet when he visits the old folks in Montreal he's flown there by a Objiway, on a plane fixed by a Objiway, designed by a Objiway.
      Yet not actually Obijiways but guys born in cAnada of Ojibway biological descent.
      This is the what evolutions come too. come to think of this is what ID folks say it was back in the '30.s in europe.
      It never ends.

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