john hawks weblog

paleoanthropology, genetics and evolution

language evolution

  • Culture-gene coevolution and language

    Sat, 2013-06-15 15:28 -- John Hawks

    Simon Fisher and Matt Ridley, in a recent essay in Science, discuss the relationship between the genetic mutations that distinguish humans and other primates and the behavioral traits that those mutations may underlie [1]. They draw upon the lactase persistence example, in which the dietary "niche" of milk consumption must have been present before the causal mutations for lactase persistence were selected in human populations. The essay mistakenly lumps alcohol "tolerance" of Europeans relative to Asians in with lactase persistence as an example of adaptation after the fact (citing Guns, Germs and Steel for this fact); in reality, the Asian flushing reaction is the novel trait, apparently driven by natural selection on a new mutation within Asia.

    In any event, the general point is that several Holocene examples show that humans have adapted to new cultural innovations and environmental pressures only after those ecological changes were present.

    FOXP2 is not the only gene associated with the human revolution (3). However, it illustrates that when an evolutionary mutation is identified as crucial to the human capacity for cumulative culture, this might be a consequence rather than a cause of cultural change (8). The smallest, most trivial new habit adopted by a hominid species could—if advantageous—have led to selection of genomic variations that sharpened that habit, be it cultural exchange, creativity, technological virtuosity, or heightened empathy.

    This seems so uncontroversial that one may wonder why it needed to be written. But there has unfortunately been a long tradition in which some archaeologists and linguists have imagined that language emerged upon a single macromutation. The entire history of analysis of FOXP2 has underlined this assumption, as it has attained outsized visibility due to its interesting pattern of evolution. People obsess about whether it is "the" language gene. The question presupposes a saltational model of language evolution.

    In this respect, the well-known examples of Holocene human adaptations may not be ideal analogies for language evolution. Lactase persistence, the Duffy null blood type, and the flushing reaction are all cases where one large-effect mutation really was strongly selected in response to a novel environmental pressure. But those examples are surely the tip of the iceberg when it comes to the full picture of recent adaptation. Most human phenotypes are complex, involving many genes, and evolution of such traits in response to Holocene environmental changes almost certainly involved changes in the frequencies of standing genetic variants of much weaker effect. It is difficult for us to discover these gene networks, because of the small effect sizes and deeper history of the variants. But that pattern of multigenic adaptation must be much more likely to characterize language evolution.

    Did talking come first? A true coevolution would have bootstrapped behavior, learning and genetic adaptations together.

    References

    1. Fisher SE, Ridley M. Evolution. Culture, genes, and the human revolution. Science. 2013;340(6135):929-30.
    Tags: 
    language evolution
    language
    adaptation
    recent selection
    Holocene
    coevolution
    gene-culture coevolution
    Synopsis: 
    An argument that culture preceded genetic adaptation in language evolution

  • Quote: Hockett and Ascher on signs and symbols

    Fri, 2013-05-31 17:28 -- John Hawks

    From "The human revolution", by Charles Hockett and Robert Ascher, footnote 2 [1]:

    Some recent discussions (e.g., Critchley 1960) try to deal with the emergence of language merely in terms of the contrast between "sign" and "symbol"; intentionally or not, these treatments give the impression that our ancestors acquired language in a single enormous leap. Anyone aware of the intricacy of design of every human language knows that such a leap was impossible; there had to be steps and stages. The contrast between "sign" and "symbol", first carefully discussed by Langer (1942), then adopted and developed by White (e.g., 1949, 1959), is too gross to serve.

    References

    1. Hockett CF, Ascher R. The human revolution. Current Anthropology. 1964;5:135–168.
    Tags: 
    language evolution
    language
    semiotics
    history of anthropology
    quotes

  • Brains in a haystack

    Tue, 2013-04-30 09:45 -- John Hawks

    An essay by Gary Marcus, in the new online science magazine, Nautilus: "Where uniqueness lies".

    In short, humans may live very differently than chimpanzees, but the structural plans of our biology necessarily can represent only modest tinkerings to the genetic material that we inherited from our last common ancestors. Language, regardless of how it is instantiated in our brain, represents a comparatively tiny cognitive enhancement relative to the mental machinery we inherited from our last common ancestor. The same is true for the underlying biology of each of our cognitive innovations.

    If it seems like scientists trying to find the basis of human uniqueness in the brain are looking for a neural needle in a haystack, it’s because they are. Whatever makes us different is built on the bedrock of a billion years of common ancestry.

    A lot of what's interesting about humans is because we reuse the ancient systems of our brains in new ways. Technology and culture both help us to exploit systems shared much more broadly among animals. This greatly complicates our attempts to show what is really different about the biology of the human lineage, because shallow differences based on recent behavioral innovations abound.

    Tags: 
    brain
    brain evolution
    brain function
    language evolution

  • Speaking of Neandertal FOXP2

    Tue, 2013-01-29 00:39 -- John Hawks

    Tomislav Maricic and colleagues from Svante Pääbo's group have reported finding a regulatory change in the gene FOXP2 that may be of relevance to the evolution of human speech [1]. To telegraph the conclusion, the paper does not demonstrate that Neandertals or Denisovans were different from humans in speech or language-relevant phenotypes.

    Most important, a substantial number of living people share the ancestral genotype inferred for Neandertals and Denisovans for the site considered in the study. It is a genetic change within living people that may have been important, but it is an instance where human variation includes the Neandertal genotype.

    I'm going to let the paper's mini-review do the work of describing the background to the study:

    Among humans, sequence variation around exon 7 shows an excess of derived nucleotide variants at high frequencies and of rare nucleotide variants, indicating that the region has been affected by a selective sweep (Enard et al. 2002; Zhang et al. 2002; Yu et al. 2009). It has been estimated that this happened within the last 200,000 years (Enard et al. 2002) or 55,000 years (Coop et al. 2008). Because it was initially assumed that at least one of the two amino acid substitutions were the cause of the sweep, it was expected that at least one of them would not be present in Neandertals, who shared a common ancestor with modern humans 370–450,000 years ago (Green et al. 2010). However, both nucleotide substitutions were found in two Neandertals from Spain (Krause et al. 2007) as well as in Neandertals from Croatia (Green et al. 2010), and in Denisovans, an extinct Asian hominin group related to Neandertals (Reich et al. 2010). Furthermore, it was found that linkage disequilibrium extends across exon 7 in present-day humans, which is not expected if one of the two amino acid changes in exon 7 was the target of selection (Ptak et al. 2009). Hence, although at least one of the two amino acid changes is very likely evolutionarily relevant given the functional data and the conservation of FOXP2, they are not likely to be the cause for the selective sweep. Assuming that a sweep did occur, it must therefore be caused by some other variant in the region, possibly affecting the regulation or splicing of FOXP2.

    It was a big story that humans had a recent sweep in this gene, eliminating most of the variation, and that humans are different from other primates in the coding sequence. But the apparent timing of the sweep did not make sense in combination with the observation that Neandertals share the human coding sequence.

    One resolution of these observations is the hypothesis that the human version of FOXP2 simply came from Neandertals. I wrote about a short paper by Graham Coop and colleagues in 2008 that went along similar lines ("FOXP2 is really recent, it really did introgress (if it's not contamination)"). Coop and colleagues substantiated the hypothesis of a recent selective sweep, but at the same time they did acknowledge that selection on some other linked locus might account for the evidence.

    Maricic and colleagues have found another linked genetic change that could account for the sweep. In their scenario, the sweep was only the most recent of possibly several changes under selection to this gene. This most recent one involved a regulatory change within exon 7 of the gene that did not affect the coding sequence at all.

    The sequence analysis carried out by Maricic and colleagues is very straightforward. They simply resequenced the gene region from Neandertal specimens to get a list of sites where Neandertals and Denisovans do not carry a derived human variant, and then resequenced the gene in 50 humans to see how many of the derived human mutations are high-frequency. The one they identify is both high-frequency and affects a candidate regulatory site. The site is a binding site for the transcription factor POU3F2. The rest of the paper documents their attempts to demonstrate an effect of this site on gene regulation in tissue culture. They conclude:

    The transcription factor POU3F2 is expressed exclusively in the central nervous system (Schreiber et al. 1993), more specifically in postmitotic neurons and glia (Hagino-Yamagishi et al. 1997). Within the central nervous system, FOXP2 is expressed in postmitotic neurons (Ferland et al. 2003). Thus, it is reasonable to assume that POU3F2 regulates expression of FOXP2 in neurons. It is furthermore interesting that position 114076877 is located at the point in intron 8 of the FOXP2 gene where the pattern of allele frequencies among humans indicates that a functional change occurred that could be responsible for a positive selective sweep affecting the FOXP2 gene during the last 50,000 years (Coop et al. 2008). It is noteworthy that this is the only nucleotide variant in that region where the majority of present-day people carry a derived variant that is not present in Neandertals and Denisovans. Thus, it is possible that this change was positively selected recently during the evolution of fully modern humans.

    However, the ancestral allele shared by Neandertals and Denisovans is also fairly common in some human populations today. As Maricic and colleagues conclude, the obvious thing to do is look at homozygote carriers of the allele to see if they're different from noncarriers:

    The ancestral allele occurs at frequencies of ∼10% in some African populations (supplementary table S6, Supplementary Material online). Therefore, individuals homozygous for the ancestral allele can be expected to occur at a frequency of approximately 1% in the population. In such individuals, the phenotype of the ancestral allele should be observable even if is recessive to the derived allele. Further work will explore the phenotypes of such homozygous carriers of the ancestral allele and the consequences of the substitution at position 114076877 on FOXP2 transcription in model systems.

    This all seems logical. We may not be able to say that Neandertals were just like us in FOXP2 -- but that's because we're not all alike. They're just like some of us.

    The only thing I would add is that the number of humans covered by the study is still quite small. The paper examined only 50 individuals from the HGDP set; additionally they considered the 1000 Genomes data. It is interesting that the Neandertal-Denisovan ancestral allele at this site is not present in several of the samples outside Africa in the 1000 Genomes data, but it is present in two of the American samples, and in all the African samples. So although the region looks like it was positively selected at some point during the last 100,000 years or so, we still can't yet say that the ancestral allele carried by Neandertals was disadvantageous within later populations.

    Larger samples would settle that question. In the meantime, this study does point the way toward a wider analysis of differences in gene regulation among archaic human genomes.

    References

    1. Maricic T, Günther V, Georgiev O, Gehre S, Curlin M, Schreiweis C, Naumann R, Burbano HA, Meyer M, Lalueza-Fox C, et al. A Recent Evolutionary Change Affects a Regulatory Element in the Human FOXP2 Gene. Mol Biol Evol. 2012.
    Tags: 
    language evolution
    brain development
    brain
    Neandertal DNA
    Neandertals
    Denisova
    Synopsis: 
    A discovery of gene regulation differences in FOXP2 may explain the variation of the gene in recent and archaic people.

  • Left-handed termite-fishing

    Mon, 2012-11-05 16:26 -- John Hawks

    Stephanie Bogart and colleagues, working at the chimpanzee field site of Fongoli, Senegal, have a new paper on handedness in these wild primates [1]. Paleoanthropologists have long been interested in handedness as it may provide evidence about lateralization of function in the brain. It is interesting that humans are highly brain lateralized for language and for tool use, suggesting that these functions may be connected in their evolutionary history.

    Chimpanzees have a homolog of Broca's area, which does not show substantial lateralization in structure [2]. But chimpanzees do show a hand preference in many of their behaviors, including when they are communicating with gestures [3]. Some studies have tied that kind of lateralization of gesture behavior to evidence for lateralization in brain function [4]. A criticism is that these kinds of studies are done with captive chimpanzees, and may not reflect the evolution of hand preference or communication in natural contexts.

    Which brings me to the reason for pointing to Bogart and colleagues' work, which includes my favorite element, the one-paragraph mini-review of the literature:

    In support of this argument, some authors suggest that data from captive and wild primates, especially chimpanzees (Pan troglodytes), produce conflicting results with regards to data on handedness (McGrew and Marchant,1997). Studies in captive chimpanzees reveal population-level right handedness for a number of actions or tasks including throwing, coordinated bimanual activities, manual gestures and grooming (Hopkins,2006; Hopkins et al.,2007, 2010, 2011, 2012). In contrast, reports in wild chimpanzees fail to show population-level bias in spontaneous activities such as scratching, simple reaching, or plucking (Mahale, Tanzania: Corp and Byrne,2004; Gombe, Tanzania: Marchant and McGrew,1996; McGrew and Marchant,2001) or on measures of tool use such as nut-cracking (Bossou, Guinea: Biro et al.,2003; Humle and Matsuzawa,2009), termite fishing (Gombe, Tanzania: McGrew and Marchant,1992; McGrew and Marchant,1996), ant dipping (Mahale, Tanzania: Marchant and McGrew,2007) and leaf sponging (Bossou, Guinea: Biro et al.,2003; Tai, Ivory Coast: Boesch,1991), though some question these claims (Hopkins and Cantalupo,2005; Hopkins,2006). One limitation in attempting to compare findings between wild and captive chimpanzees is the fact that the measures often differ between settings. Most studies of handedness in the wild focus on tool use while hand preference research with captive chimpanzees rarely simulates tasks that model different forms of tool use demonstrated in African populations (Hopkins and Cantalupo,2005). A second limitation of studies in wild chimpanzees is that the sample sizes are often small, and therefore detecting population-level preferences is difficult due to a lack of statistical power (Hopkins,1999; Hopkins and Cantalupo,2005). Indeed, when data on some tool use measures, such as leaf dipping, ant dipping, and termite fishing are combined across study sites or from different studies, population-level handedness is found in wild chimpanzees (Hopkins and Cantalupo,2005).

    They find that at Fongoli chimpanzees prefer to termite-fish using their left hands. This is consistent with earlier observations at Gombe, Tanzania, and the authors suggest that it may reflect a greater sensitivity to tactile feedback in the right hemisphere of the chimpanzee brain, as has been shown in some human work. Either that, or it is really a two-handed task in which the right is taking on more of a grasping role:

    Second, we have observed that some of the chimpanzees will, after extracting the termite stick, rest it on their opposite hand or wrist and then eat the termites by bringing their wrist to their mouth. In this explanation, the chimpanzees may use their left hand for the probing action to leave the right hand free to aid in consuming the biting insects. In this sense, the hands are working in a complementary, bimanual fashion. In addition to this, the nonprobing hand is often used to pick up termites that are on the outside of the mound, thus the left hand preference for probing could be a result of a right hand preference for grasping. The cognitive and motor factors discussed here may influence termite fishing laterality in conjunction with each other.

    That puts a different spin on the evolution of handedness in humans, considering that stone tool manufacture is certainly a two-handed task, as are most actual uses of stone tools for cutting and chopping.

    References

    1. Bogart SL, Pruetz JD, Ormiston LK, Russell JL, Meguerditchian A, Hopkins WD. Termite fishing laterality in the fongoli savanna chimpanzees (Pan troglodytes verus): Further evidence of a left hand preference. American Journal of Physical Anthropology. 2012:n/a - n/a.
    2. Schenker NM, Hopkins WD, Spocter MA, Garrison AR, Stimpson CD, Erwin JM, Hof PR, Sherwood CC. Broca's area homologue in chimpanzees (Pan troglodytes): probabilistic mapping, asymmetry, and comparison to humans. Cereb Cortex. 2010;20(3):730-42.
    3. Hopkins WD, Cantero M. From hand to mouth in the evolution of language: the influence of vocal behavior on lateralized hand use in manual gestures by chimpanzees (Pan troglodytes). Developmental Science. 2003;6(1):55 - 61.
    4. Taglialatela JP, Cantalupo C, Hopkins WD. Gesture handedness predicts asymmetry in the chimpanzee inferior frontal gyrus. NeuroReport. 2006;17(9):923 - 927.
    Tags: 
    chimpanzees
    language evolution
    language
    handedness

  • Liveblog of ScienceNOW on Neandertals, Dikika

    Wed, 2012-10-10 22:09 -- John Hawks

    Now watching the NOVA ScienceNOW about "What makes us human".

    9:06: "The idea of another species of humans sharing our cities isn't that far-fetched. 30,000 years ago, there were at least four different kinds of humans sharing the earth, including the Neandertals"

    The introduction to Neandertals isn't bad, although I really don't like it when people say "the ones who stayed in Africa became us" -- that minimizes the contribution of other people, and glosses over the possibility that some ancient Africans didn't become "us", or were among the ancestors of some Africans but not all.

    9:08: "Daniel Lieberman from Harvard looks for answers in the way human heads evolved" -- Lieberman: "What makes you different from Neandertals is basically above the neck."

    9:09: Now Pogue is showing himself in a makeup studio being made into a Neandertal character. Back to Lieberman explaining how the Neandertal head is different from ours. It's really interesting to hear him describe this, because the description is completely typological -- there's no conception here of variation within Neandertals or within humans.

    9:11: OK, the makeup transformation is complete. I don't want to cast aspersions on the artists, but the result doesn't compete with the makeup jobs on Face/Off.

    Pogue goes walking down a city street. I don't see anybody noticing..but of course there's a cameraman following him around.

    9:13: Differences in the shape of the brain. Lieberman "wouldn't bet his mortgage" on human brains being better than Neandertals.

    Now Pogue is presenting several just-so stories about why we were superior to Neandertals. He dismisses these as "speculation" and starts talking about the Neandertal genome. We see a Max Planck scientist grinding up some bone with a Dremel tool.

    9:15: Yay, Ed Green!

    Green: "They had sex, they had descendants, we find this trace in our DNA today. Amazing."

    9:18: This is the fourth show I know of where they have a presenter get their DNA sampled to find the Neandertal fraction. It's really cool that they are getting this news out there.

    Green shows Pogue a part of chromosome 12 where he has a Neandertal nucleotide. They're showing a laptop screen with a slot machine-like display of nucleotides. I suppose it was really a blank screen and they did it in post-production. Either that, or I have to get the slot machine DNA typing program!

    9:20: "We may not see Neandertals among us, but they are still here, within us."

    Still walking down the street. An older lady seems to have decided Pogue is some kind of freak.

    Oh, no! An animated Neandertal in drag! She/he is putting on makeup (this is about the shells and pigments associated with Neandertals). I have only this to say: Through the Wormhole has way better short animations than ScienceNOW.

    Whew, that was over quick. Now he's on to the origin of language.

    9:22: It's Dave Frayer! He's got a suitcase with skulls inside. Man, it would be cool if it were like the one in Pulp Fiction!

    OK, well, it's cooler to have one with skulls inside, I guess.

    Going through Homo erectus brain size. A symmetrical stone tool becomes a way to look into the cognitive abilities of early Homo.

    9:26: On to Dietrich Stout, who is discussing the pathways in the brain used for stone tools. He works with Bruce Bradley, expert stone knapper, who is giving Pogue a lesson in toolmaking.

    With toolmaking we're looking at complex, sequential thought. Bradley: "Because what are we looking at with language, it's complex sequential thought"

    9:29: Now Cynthia Thompson, who is looking at people with brain injuries that lead to aphasia. "Agrammatic aphasia patients share a common characteristic: damage to the left hemisphere of the brain, which contains an area called Broca's area...does Broca's area have anything to do with stone toolmaking?"

    9:31: Going into a scanner, where people are watching stone toolmaking via a projector, on the argument that watching an activity and doing the activity involve the same brain area. "Watching the video of simple choppers resulted in mild activity in Broca's area, but watching the video of making a handaxe caused four times as much activity"

    9:34: A short interlude on babies learning language.

    9:35: Looking at babies learning to laugh. Gina Mireault is studying babies smiling and laughing. "What we found with these very young babies, is that when we tell parents to make their babies laugh, they do some very outrageous things. Laughter is irresistible"

    9:37: Now at the Cincinnati Zoo to see if animals laugh. Pogue tickles a penguin -- "he's laughing" -- "no, that's the noise they make when they want to breed"

    Pogue is really talented at this part, he totally commits himself to being silly in the name of science.

    Marina Davila-Ross is studying primate laughter. They are at the Stuttgart Zoo with gorillas. She collected sounds from all the great apes being tickled. Super cool audiogram images of the laughter sounds going from most distant -- orangutans -- to humans across the phylogenetic tree. Gorillas always use the same kind of panting laughter, as a part of horseplay.

    9:42: Now with psychologist Michael Owren, looking at acoustic models of laughter sounds in people.

    9:43: Pogue asks a great question: "How did that make me have more babies?" The program gives an answer (for laughter and social relationships) but it's great that they edited it to emphasize this question.

    9:44: Zeray Alemseged in Ethiopia: "I went to start the first Ethiopian-led project in paleoanthropology ever, but it wasn't easy". The show gives a great short biography of Alemseged. This is an awesome segment.

    9:48: Now at Dikika. They do a great job illustrating the discovery of the skeleton.

    9:50: Don Johanson discussing how we "did not instantly become human".

    9:51: "Day after day, for six years, Zeray chipped away at the piece of stone." They're comparing the Selam teeth to apes and humans, inferring its age and pattern of development. The show has him at a computer with Fred Spoor examining CT data.

    9:53: Describing the hoopla that arose upon the publication of the Dikika skeleton. This has been a great 12-minute segment on Alemseged.

    9:55: And that's the program. Very well done, a range of segments that go together very naturally. They really did save the best for last, but really everyone in the program did a great job.

    Tags: 
    tv
    Neandertals
    Neandertal DNA
    A. afarensis
    Ethiopia
    Zeray Alemseged
    language evolution
    Synopsis: 
    The magazine program has segments on Neandertal DNA, language evolution, and Zeray Alemseged

  • Perils of talking to apes

    Fri, 2012-09-28 10:28 -- John Hawks

    Barbara King comments on Koko, Kanzi and Panbanisha, "Thoughts On Three Famous 'Language Apes'".

    For decades, the Gorilla Foundation, run by the scientist Penny Patterson, has maintained — based on Koko's own use of sign language — that Koko would like to have a baby. Recently the Foundation posted this video clip, in which Koko is presented, verbally and in diagram form, with four complicated choices about "family planning."

    Patterson, at the end of the clip, affirms her interpretation that Koko grasped all of the options presented to her. The idea is that Koko, by pointing to one of the four diagrammed choices, can and should help make decisions that involve the reproductive activities and the welfare of other gorillas. This raises ethical issues, to say the least.

    We haven't come to the apes in my Biology of Mind course yet, but we were discussing the nineteenth-century origins of ethology yesterday. The initial move toward a science of animal behavior was possible because anthropomorphic accounts of animal behavior were set aside. The apes pose a recurring challenge to the rejection of anthropomorphism, because some of their behavioral capabilities really are homologous with ours. The cognitive border between ape and human may be a no-mans land, with one or two traits occasionally crossing the frontier to the other side. King's last word is fitting -- an ape can never grasp the complexities of the human world...yet neither can we fully grasp the complexities of theirs.

    Tags: 
    apes
    chimpanzees
    gorillas
    cognition
    behavior
    language evolution

  • Chomping Chomsky

    Mon, 2012-09-03 13:07 -- John Hawks

    I ran into Deevy Bishop's review of a recent book by Noam Chomsky and James McGilvray, titled The Science of Language: Interviews with James McGilvray.

    As someone who works on child language disorders, I have tried many times to read Chomsky in order to appreciate the insights that he is so often credited with. I regret to say that, over the years, I have come to the conclusion that, far from enhancing our understanding of language acquisition, his ideas have led to stagnation, as linguists have gone through increasingly uncomfortable contortions to relate facts about children’s language to his theories. The problem is that the theories are derived from a consideration of adult language, and take no account of the process of development. There is a fundamental problem with an essential premise about what is learned that has led to years of confusion and sterile theorizing.

    Bishop's post led me to a review of the book by Language Log writer Geoffrey Pullum, "The Science of Language: Interviews with James McGilvray". The review is bad:

    It continues thus, jargon jostling with loose conjecture and dogmatic assertions. Chomsky avers that words never refer to anything in the world; that "the entire discussion of the last century or so" about relations between physics and chemistry "was crazy"; that Darwin was wrong and evolution by natural selection (like Skinnerian behaviourism) cannot work; that there was no "serious research" on morality before 2000; that the practice of debating "is a tribute to human irrationality"; etc.

    It gives rise to a spectacular train wreck of a comment thread, with a heated exchange between Pullum and McGilvray.

    I'm starting my Biology of Mind course tomorrow, and so once again I'll be posting more neuroscience and psychology-related material than usual. Chomsky is quite a lot like Freud -- he has written an immense corpus, developed an idiosyncratic model of the mind, and is surrounded by a coterie of true believers. He has been the most prominent objector to the idea that language evolved as an adaptation in ancient humans. Understanding this view helps to focus attention on how we use adaptive models in biology and how they can apply to behavior.

    And how model-builders can shift some assumptions to adapt to changing scientific data.

    Tags: 
    Noam Chomsky
    psychology
    language
    language evolution
    history of psychology

  • The cultural tool

    Sat, 2012-03-24 23:28 -- John Hawks

    The Guardian interviews Daniel Everett about his new book, Language: The Cultural Tool. Which I will mention, has one of the worst covers ever. It's like the publisher is trying to keep it on the shelves:

    Anyway, Everett is well-known for his long-term work among the Pirahã, whose distinctive language has challenged many of linguists' assumptions about the nature of human language. Well, generative linguists' assumptions, anyway. The interview discusses the challenge Everett's findings pose for Chomsky's theories of language.

    So what do you think is the lesson of all this from a linguistic point of view?

    The lesson is that language is not something mysterious that is outside the bounds of natural selection, or just popped into being through some mutated gene. But that language is a human invention to solve a human problem. Other creatures can't use it for the same reason they can't use a shovel: it was invented by humans, for humans and its success is judged by humans.

    The Chronicle of Higher Education has a longer article covering Everett's book: "Angry Words". In the article, we see that a theoretical debate in linguistics has turned into a full-blown fracas:

    In 2007, Everett heard reports of a letter signed by Cilene Rodrigues, who is Brazilian, and who co-wrote the paper with Pesetsky and Nevins, that accuses him of racism. According to Everett, he got a call from a source informing him that Rodrigues, an honorary research fellow at University College London, had sent a letter to the organization in Brazil that grants permission for researchers to visit indigenous groups like the Pirahã. He then discovered that the organization, called FUNAI, the National Indian Foundation, would no longer grant him permission to visit the Pirahã, whom he had known for most of his adult life and who remain the focus of his research.

    He still hasn't been able to return. Rodrigues would not respond directly to questions about whether she had signed such a letter, nor would Nevins. Rodrigues forwarded an e-mail from another linguist who has worked in Brazil, which speculates that Everett was denied access to the Pirahã because he did not obtain the proper permits and flouted the law, accusations Everett calls "completely false" and "amazingly nasty lies."

    The Chronicle article is really juicy, with lots of linguists saying bad things about both Everett and Chomsky. It really misses the action in present-day linguistics, however, because the Piraha are only a small part of the overall challenge to Chomsky's ideas.

    Tags: 
    language evolution
    language
    Noam Chomsky

  • Gorilla genomics and hearing evolution

    Thu, 2012-03-08 00:37 -- John Hawks

    The Nature News story on the gorilla genome includes this section relevant to the evolution of hearing in gorillas and humans:

    Some of these rapid changes are puzzling: the gene LOXHD1 is involved in hearing in humans and was therefore thought to be involved in speech, but the gene shows just as much accelerated evolution in the gorilla. “But we know gorillas don’t talk to each other — if they do they’re managing to keep it secret,” says Scally.

    This weakens the connection between the gene and language, says [Wolfgang] Enard. “If you find this in the gorilla, this option is out of the window.”

    This is one of the genes that I have been working on with reference to its acceleration on the human lineage. It is a mistake to view the evolution of hearing to be directed specifically to language; instead human and gorilla lineages are both adapting to an aural environment different from ancestral hominoids. In both these lineages, there was an increase in body size and reduction in the mean frequency of vocalizations, enough to prompt adaptive changes. In humans, we have had additionally the addition of language as a communication system, which has its own auditory requirements. The connection with language is only indirect, in that human-specific changes to this and other genes provide evidence of adaptive change in the auditory system.

    Tags: 
    hearing
    gorillas
    genomics
    positive selection
    language evolution

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Neandertals

For years, I've worked on their bones. Now I'm working on their genes. Read more about the science studying these ancient people.

Denisova

From a finger bone of an ancient human came the record of a completely unexpected population. My lab is working on the science of the Denisova genome.

Acceleration

The advent of agriculture caused natural selection to speed up greatly in humans. We're uncovering some of the ways that populations have rapidly changed during the last 10,000 years.

Malapa

Just outside Johannesburg, the Malapa site is producing some of the most exciting finds in human evolution. This site is the headquarters of the Malapa Soft Tissue Project.