john hawks weblog

paleoanthropology, genetics and evolution

cognition

  • Mailbag: The Eemian: what gives?

    Wed, 2012-10-31 21:12 -- John Hawks

    I wandered into your site after searching for Eemian and human evolution.

    The general consensus is that anatomically modern humans were in Africa 150-200K year ago. During the Eemian interglacial these humans presumably had similar opportunities to migrate and develop agriculture as humans did during the Holocene. Yet apparently they didn't.

    Do have any thoughts on why this is so?

    Of course, a smaller population base at the beginning of the Eemian than at the beginning of the Holocene might account for this but I would think that with favorable climatic conditions a small population at the start would rapidly increase.

    Another reason might be that anatomically modern humans at the beginning of the Eemian lacked something in the neurological wiring to build modern culture.

    Thanks for writing. Indeed, this very question has interested archaeologists for a long time. The multiple independent origins of domestication and agriculture seem to have a demographic explanation. That means that the Eemian, with its environmental profile so similar to the Holocene, might be expected to have given rise to the same events. Surely Eemian west Asia was more similar to Holocene west Asia than the latter was to Holocene Mexico.

    Archaeologists' explanations are basically as you describe, although I could add a few:

    1. Maybe the Eemian wasn't really so similar to the Holocene, despite appearances.
    2. The technology in pre-Eemian times may not have allowed population growth in response to the ameliorating climate to the extent that Upper Paleolithic-era technologies did prior to the Holocene.
    3. The cognitive abilities of Eemian-era humans may not have enabled effective response to changing climate.
    4. The cultural systems of pre-Eemian times may have been more highly based on population regulation/limits to growth, thereby enabling the population to respond without the overgrowth that necessitated sedentism and ultimately domestication of plants.
    5. Demographic intensification in Africa and resulting mass migration DID happen in the Eemian, and we call this the out-of-Africa event.

    I will note that there is now some evidence of intensive collection of cereals in tropical Africa before the Eemian, so this problem may yet become more complex. One of the reasons I follow the Holocene domestication literature so closely is to try to perceive what social dynamics were shared among terminal Pleistocene peoples -- because some critical factors must have been absent pre-Eemian, but we don't know which!

  • 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.

  • Neandertals lacked mental eminence

    Sun, 2012-09-23 18:11 -- John Hawks

    If you care about Neandertal behavior and haven't read this 2004 article by John Speth, you really should treat yourself: "News flash: Negative evidence convicts Neanderthals of gross mental incompetence" [1]. I'm using the paper as a reference in a new manuscript, and so re-reading and giggling along the way:

    Neanderthals didn’t make blades, or at least not as often, or maybe not as well, as moderns did (they didn’t make microliths either, or stainless steel for that matter, but they did make great triangles; unfortunately rectangles are ‘in’ these days, not triangles). They didn’t carve bone or ivory (nor did they work fiberglass, though they may have carved a lot of wood, judging by recent use-wear evidence). They didn’t paint the walls of their caves, despite ample opportunity to do so (but, then, painting cave walls, even in the Upper Paleolithic, was truly the exception, not the rule). They did have spears, we have some of them (this, no doubt, is what all of their woodworking was about), but try as they might they just couldn’t throw them (the points that somehow managed to find their way through hair and hide of sizeable prey to become squarely embedded in solid bone notwithstanding). They had no large formal fireplaces (what’s wrong with some of the hearths at Kebara?), so they couldn’t sit cozily face-to-face around the fire at night holding hands, roasting marshmallows and singing campfire songs, hence they must have lacked true language (and Girl Scouts; in fact, the conspicuous absence of marshmallows throughout the Upper Paleolithic clearly testifies to the lack of language as we know it until very late in the Holocene).

    If you haven't been following paleoanthropology for long, you may find it difficult to believe that Serious Scientists have proposed some of the nonsense that Speth skewers (for example, that Neandertals lived bison-like in cow-calf and bull groups who only joined when rutting). Speth's tour through bad ideas is a ribald pleasure.

    Yet there is an important point in the paper, which is why I'm citing it today: The material record of Neandertals is in many respects within the range of hunter-gatherers who are unquestionably modern humans:

    What is the relevance of the North American record to the question of Neanderthal’s mental hardware? Simply this: most sites that date to the Paleo-Indian and early Archaic periods – periods that together last some 5,000 to 6,000 years and represent nearly half of the known occupation span of the New World – have little or no evident internal structure (unless you want to count ‘patches’ or ‘scatters’ as structure; the rare high-resolution examples share the same humdrum ‘carnivore dichotomy’ that was used to torpedo the poor Neanderthal); there are few if any formal hearths (isolated patches and lenses of ash are much more the norm); burials are extremely rare or absent altogether, and those few that exist have little or nothing in the way of ornaments or grave accompaniments; huts are generally absent or very controversial; and art of any non-perishable sort is virtually non-existent (they certainly didn’t paint cave walls; in fact, we are hard put in most cases to find anything that even remotely smacks of symbolism). If we were to use the same criteria that we apply to Neanderthals, we would have to conclude that the inhabitants of North America up until only a few thousand years ago were – to put it in politically correct terms – ‘cognitively challenged’. The parallels with the record of the Middle Paleolithic are even more striking if we exclude from consideration the few dry caves in western North America and waterlogged sites in Florida of late Paleo-Indian and early Archaic age which have miraculously preserved tantalizing traces of perishable basketry, textiles and other unusual items.

    Then around 5,000 years ago, give or take a millennium, came North America’s counterpart to Eurasia’s Upper Paleolithic ‘revolution’. We suddenly see an explosion of art – intricately shaped or carved and sometimes engraved ‘exotica’ of shell, antler, bone, stone, tortoise shell and native copper, including cups, tubes, pendants, beads, pins, rattles, atlatl hooks, bannerstones and gorgets; there are also remnants of probable ‘medicine’ bags, traces of textiles, decorated baskets and ubiquitous red ochre – the whole nine yards. Many of the raw materials came from distant lands – marine shell from the Gulf of Mexico, shark’s teeth from the mid-Atlantic states, copper from Lake Superior, galena and mica from Illinois and the Appalachians. This is also the time when we begin to see burials clustered together in real cemeteries, not just peppered here and there over the archaeological landscape; and many of these burials are elaborately decked out with ornaments and other ‘exotica’, so much so at times that we begin to speculate about the beginnings of prestige enhancement and wealth display, about ‘big men’, about reduced mobility and increasing conflict, about the growing importance of inter-group exchange and political alliances, about the very seeds of societal inequality and hierarchy. This is the bread and butter of North American archaeology. And, while there is lots to disagree and argue about (particularly about what is ‘cause’ and what is ‘effect’), all seem to agree that in some form or other what we are seeing over the course of the Archaic is the playing out of gradually increasing populations that were slowly filling in the landscape, reducing people’s ability to ‘vote with their feet’ when things got tough, and thereby compelling them to begin playing with alternative economic, social and political strategies for maintaining the delicate balance between war and peace – in a word, social, technological, economic and political intensification. No one, of course, would believe for a nanosecond that in the artless and styleless silence of the early Archaic we are dealing with a cognitively impaired proto-human.

    The Paleo-Indian/Archaic period transition is obviously not a perfect analogy for the Upper Paleolithic transition in Europe. Speth himself is explicit that this example does not prove anything about Neandertals.

    But it does illustrate a double-standard. Recent archaeological peoples are prima facie "modern" in behavior without showing evidence for "symbolic" interactions. With Paleo-Indian sites, the subsistence strategy itself argues for a complex logistical organization, even though habitation sites, kill sites and artifacts comport with the lack of structural complexity of many hunter-gatherer groups in the ethnographic present. Some scientists have presented similar arguments for Neandertals.

    Personally, I think that "cognitive modernity" is a red herring. Today's people learn some kinds of technical and symbolic complexity that were never present in ancient peoples. Some people living today in Western cultures, despite all our educational efforts, fail to attain levels of technical knowledge that are regular outcomes for the majority of people in the same environment. Human performance varies continuously.

    I assert that it is unreasonable to suppose that Neandertals had a "stupid gene". If so, it should be just as unreasonable to suppose that a "smart gene" could explain the evolution of human cognition during the last 100,000 years. These unrealistic assumptions are widespread, and impede our understanding just as thoroughly as assumptions about the nature of biological species impeded our understanding of Neandertal ancestry of living human populations. Some archaeologists have concluded that Neandertal cognition is an either/or proposition. Some look at Neandertals, find a lack of evidence that they behave identically to later people, and conclude that the Neandertals were therefore unquestionably cognitive inferiors. Others look at Neandertals, find some signs of modern-like behaviors, and conclude that Neandertals were therefore unquestionably our cognitive equals.

    Cognition in modern humans varies continuously across many axes of variation. No two humans are cognitively identical in outcomes. Nor can we appeal to "cognitive capacity", a meaningless abstraction unless we are discussing a particular structured learning environment in which the outcomes are potentially measurable. Will we someday raise a Neandertal in a human society to see whether and how they attain the skills and abilities we consider essential?

    I suspect somewhere within the broad scope of human variation in learning, we already are.


    References

    Synopsis: 
    Human variation in learning and cognition is wide. Does it encompass Neandertals?
  • Spielke profile

    Sat, 2012-05-05 12:25 -- John Hawks

    The New York Times has a long profile of developmental psychologist Elizabeth Spielke, whose work with babies has opened a window on early cognition ("Insights from the youngest minds"). The article is wide-ranging and worth sharing. I thought I'd make an note of Spielke's version of the "cathedral" model in which distinct cognitive functions are combined by executive consciousness into synthetic abilities. She denotes language as the functional glue holding the brain's abilities together:

    Dr. Spelke is also seeking to understand how the core domains of the human mind interact to yield our uniquely restless and creative intelligence — able to master calculus, probe the cosmos and play a Bach toccata as no bonobo or New Caledonian crow can. Even though “our core systems are fundamental yet limited,” as she put it, “we manage to get beyond them.”

    Dr. Spelke has proposed that human language is the secret ingredient, the cognitive catalyst that allows our numeric, architectonic and social modules to join forces, swap ideas and take us to far horizons. “What’s special about language is its productive combinatorial power,” she said. “We can use it to combine anything with anything.”

    She's in a position to test that by looking at prelinguistic children. I think there's much truth in the idea, but some functional integration must take place in any conscious organism, even without language. Language allows a complexity of expression, but complexity does not necessarily mean integration.

  • Monkey numerical distractions

    Fri, 2011-04-15 08:20 -- John Hawks

    This study has been out for a few weeks, and I've been meaning to put up a short comment about it: "Representational format determines numerical competence in monkeys", by Vanessa Schmitt and Julia Fischer [1]. The abstract:

    A range of animal species possess an evolutionarily ancient system for representing number, which provides the foundation for simple arithmetical operations such as addition and numerical comparisons. Surprisingly, non-human primates tested in ecologically, highly valid quantity discrimination tasks using edible items often show a relatively low performance, suggesting that stimulus salience interferes with rational decision making. Here we show that quantity discrimination was indeed significantly enhanced when monkeys were tested with inedible items compared with food items (84 versus 69% correct). More importantly, when monkeys were tested with food, but rewarded with other food items, the accuracy was equally high (86%). The results indicate that the internal representation of the stimuli, not their physical quality, determined performance. Reward replacement apparently facilitated representation of the food items as signifiers for other foods, which in turn supported a higher acuity in decision making.

    This seems so obvious in retrospect. An experimenter has to provide some kind of motivation or there will be no experiment. Providing food rewards in psychology tests on animals will conflate numerical cognition with food, rewards, and motivation. I'm surprised that a simple substitution of inedible items turned out to be so successful in relaxing this cognitive bias.

    As I'm thinking about the "numbers as technology" theme, I keep returning to the idea that most interesting technologies are cobbled together from heterogeneous parts. Cognitive technology is no exception. In this experiment, we see the interference between the food/reward aspects of cognition and the representation of number. To have an effective practice of number as applied to food items, an individual would have to overcome this interference.

    We might tinker with the system in different ways -- for example, we could set up a new system of behavioral rewards or we could change neurotransmitter regulation to decrease food salience. What is the dividing line between technical and natural solutions? Imagine a pill that improves monkey math by inhibiting dopamine receptors. The same inhibition might emerge by mutations to dopamine receptors -- a natural tweak that alters the threshold of technical interventions. A new reward system might seem purely technical -- in the experiment, it worked to substitute different kinds of food treats in different contexts. But then, "different" is itself a function of perception, which can be changed by changing visual and olfactory receptors. "Technical" is a matter of arranging heterogeneous things in such a way that their natural course of action achieves a desired end.


    References

  • Joshua Foer's memory racket

    Sun, 2011-04-03 11:12 -- John Hawks

    For Sunday morning (here in California, still, although it's fading into afternoon in my native land), I can point you to a book excerpt by Joshua Foer, from his new book, Moonwalking with Einstein: The Art and Science of Remembering Everything. Foer describes in detail how he set about to master the method of loci, to see just how hard it can be to compete in elite memory competitions. The number part was interesting:

    When it comes to memorising long strings of numbers, such as 100,000 digits of pi, most mental athletes use a more complex technique that is known as "person-action-object", or PAO. In the PAO system, every two-digit number from 00 to 99 is represented by a single image of a person performing an action on an object. The number 34 might be Frank Sinatra (a person) crooning (an action) into a microphone (an object). Unlike the Major System, these associations are entirely arbitrary and have to be learned in advance, which is to say it takes a lot of remembering just to be able to remember.

    I've always thought of paleoanthropology as an extreme memory competition...

  • The mystery of left lateralization

    Wed, 2011-03-09 09:22 -- John Hawks

    This morning, a timely post by cognitive neuroscientist Sophie Scott addresses the localization of language functions on the left side of the brain:

    The elephant in the room is why linguistic representations and processes are so associated with the brain’s left hemisphere in the first place. The left lateralisation of language is seen in 96 per cent of right-handed people, and is still there in 73 per cent of left-handed people (Knecht et al, 2000). It is there for men and women equally. People whose language centres are not in their left hemisphere have it in their right hemisphere: there is no evidence for people who have an intermediate, more equally divided representation of language across the left and right sides of the brain. And if the language-dominant hemisphere is damaged, the non-dominant hemisphere can take over function. Does this mean that the non-dominant hemisphere still performs linguistic functions in some low-key way? Or that it can adapt following damage to the brain (or perhaps even that it is released from some form of suppression)?

    I discussed this to some extent last week ("Language bootstrapping the brain"), but it's worth re-emphasizing: the great plasticity of language localization is really not very compatible with the hypothesis of a "language organ", except in the sense that an "organ" might self-organize upon input from the environment. It's a bit like saying the spleen could spontaneously take on some of the functions of the kidneys, in the right environment.

  • Number as cognitive technology

    Tue, 2011-03-08 21:00 -- John Hawks

    Archaeologists often define technology in terms of material products. People make stuff, and that stuff is technology.

    But there's another way to think about the stuff we make: in terms of the information we need to make it. Technology is know-how, it's skill. It's something we learn how to do. Manufacturing may have physical side effects, but it's the cognitive software that lies at the heart of technology.

    This usage is true to the etymology of the word, "technology":

    from Gk. tekhno-, combining form of tekhne "art, skill, craft, method, system," probably from PIE base *tek- "shape, make" (cf. Skt. taksan "carpenter," L. texere "to weave;" see texture).

    I mention this because, if we take this perspective on technology, then some "technology" may never be instantiated in material -- it may reside purely in the mind. That is the contention that Michael Frank and colleagues made in a 2008 paper about speakers of a language that does not have cardinal numbers above two [1]. Frank and colleagues set out to find whether this curious lack of number words causes Pirahã speakers to deal with numbers in experimental contexts differently from speakers of other languages.

    The results showed that Pirahã speakers could complete number matching tasks, using strategies that were also widespread among non-Pirahã speakers in other contexts.

    A total lack of exact quantity language did not prevent the Pirahã from accurately performing a task which relied on the exact numerical equivalence of large sets. This evidence argues against the strong Whorfian claim that language for number creates the concept of exact quantity (and correspondingly, that without language for number, any task requiring an exact match would be impossible). Instead, the case of Pirahã suggests that languages that can express large, exact cardinalities have a more modest effect on the cognition of their speakers: They allow the speakers to remember and compare information about cardinalities accurately across space, time, and changes in modality. Visual and auditory short-term memory are highly limited in their capacity and temporal extent (Baddeley, 1987). However, the use of a discrete, symbolic encoding to represent complex and noisy perceptual stimuli allows speakers to remember or align quantity information with much higher accuracy than they can by using their sensory short-term memory. Thus, numbers may be better thought of as an invention: A cognitive technology for representing, storing, and manipulating the exact cardinalities of sets.

    At the moment, my twins are making great strides in math, at least compared to their skills six months ago. Then, their mastery of number depended on counting objects, which they tracked using fingers and toes. When they got to higher numbers, they would carry out operations by envisioning imaginary fingers and toes in their heads. Now, they have learned several different strategies to break up numbers and regroup or double them, allowing them to easily add and subtract two-digit numbers.

    It's pretty cool to see it unfold, but it's essentially based on learning a technology of number. Numbers can be patterned to accomplish addition and subtraction in many ways, and with some practice and memorization, kids can attain a very rapid pace of solving problems. It's something that most of us have in their schooling somewhere, and there's nothing magical about it -- we just have to learn some algorithms and practice them.

    The Pirahã are different from speakers of other languages with more cardinal numbers, because they do not have that particular shorthand. It's a significant aid to number processing, because words and concepts provide ways to escape the limits on human short-term memory. Frank and colleagues connect this research on number to other aspects of language and cognition:

    Where does this leave the Whorf hypothesis, the claim that speakers of different languages see the world in radically different ways? Our results do not support the strongest Whorfian claim. However, they are consistent with several recent results in the domains of color ([Gilbert et al., 2006], [Uchikawa and Shinoda, 1996] and [Winawer et al., 2007]) and navigation (Hermer-Vazquez, Spelke, & Katsnelson, 1999). In each of these domains, language appears to add a second, preferred route for encoding and processing information. In the case of color, language enables faster performance in search, better discrimination, and better memory when target colors can be distinguished from distractors by a term in the participant’s language. However, verbal interference – which presumably blocks access to linguistic routes for encoding – eliminates this gain in performance, suggesting that the underlying perceptual representations remain unmodified. Likewise in the case of navigation: The use of particular linguistic devices allows (though does not require, see e.g., Li & Gleitman, 2002) efficient compressive navigational strategies. But again, under verbal interference these strategies are not accessible and participants navigate using strategies available to infants and non-human animals.

    I would have written more subtle things about the Whorf hypothesis, and maybe I will some other time.

    I very much like the idea that language itself provides the gears of a cognitive technology -- I think that is a very powerful one that we should apply more broadly in the past. It is misleading to see minimal stone tools, or the organic tools of other primates, as the simplest basis of technology. Technology begins with habits of mind, developed as strategies to better process regularities in the social environment. The powerful thing about language is that it gets in from outside. Children encounter regularities that have already taken hold in experienced minds. As I discussed last week ("Language bootstrapping the brain"), the process of language learning can proceed surprisingly well within brains with very different structural equipment.

    One other observation of interest: Color and number words were "technologies" that were acquired surprisingly well by Alex the grey parrot. Talk about a very different kind of brain!


    References

  • Hauser update

    Thu, 2010-08-19 10:17 -- John Hawks

    The Chronicle of Higher Education reports on an "internal document" from the Marc Hauser investigation: "Document Sheds Light on Investigation at Harvard". The Chronicle story begins by detailing how discrepancies in coding monkey behavioral responses first came to light, but stops short of giving fuller insight into the investigation. This extract conveys some of the breadth of what was uncovered:

    They then reviewed Mr. Hauser's coding and, according to the research assistant's statement, discovered that what he had written down bore little relation to what they had actually observed on the videotapes. He would, for instance, mark that a monkey had turned its head when the monkey didn't so much as flinch. It wasn't simply a case of differing interpretations, they believed: His data were just completely wrong.

    As word of the problem with the experiment spread, several other lab members revealed they had had similar run-ins with Mr. Hauser, the former research assistant says. This wasn't the first time something like this had happened. There was, several researchers in the lab believed, a pattern in which Mr. Hauser reported false data and then insisted that it be used.

    The article also extracts an e-mail from Hauser to his graduate students at the time of the incident. It's not shocking in its tone -- certainly no more than many of those leaked climate e-mails -- but it does show the kind of pressure he was imposing upon the graduate students working on his experiments.

    (via Greg Laden)

  • Marc Hauser misconduct findings

    Wed, 2010-08-11 00:41 -- John Hawks

    Maybe by now everybody has seen the story about Harvard psychologist Marc Hauser:

    Harvard University psychologist Marc Hauser — a well-known scientist and author of the book “Moral Minds’’ — is taking a year-long leave after a lengthy internal investigation found evidence of scientific misconduct in his laboratory.

    The findings have resulted in the retraction of an influential study that he led. “MH accepts responsibility for the error,’’ says the retraction of the study on whether monkeys learn rules, which was published in 2002 in the journal Cognition.

    The issue seems to revolve around interpreting subjective data on animal cognition. The article does not make clear whether Hauser or someone in his lab skewed data deliberately; no one has yet gone on record to specify the actual misconduct.

    The problem of subjective data is not unique to Hauser's work but is systemic in the field of primate cognition. It reminds me of some discussion in Jeremy Taylor's recent book Not a Chimp: The Hunt to Find the Genes that Make Us Human. There's the issue of whether experiments are designed clearly enough to yield conclusions. Then there's the second issue of whether observations are replicable, or whether they result only from somewhat "wishful" researchers. Such experiments often get heightened scrutiny, but rarely is there clear misconduct. That makes this a really shocking case.

    (via Gene Expression, and A Replicated Typo)

    UPDATE (2010-08-11): More from DrugMonkey. And a very nice post from Melody Dye who puts the issue in the context of other problems pervading psychology research.

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Neandertals

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Malapa

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