Click on the cover to link to OUP's e-catalogue then turn to the biology section.

Interview Podcast with George Miller

Interview Podcast with George Miller
Click on the pic to link to the NOT A CHIMP podcast on Blackwell's Website

Preface to "Not A Chimp: The Hunt For The Genes That Make Us Human"

In many ways, this book is born out of frustration for a professional career in popular science television where ideas about comparative primate cognition, and the similarities and differences between us and our primate relatives, have continually circled me but constantly evaded my grasp in terms of the opportunity to transform them into science documentary. On the plus side, keeping a watching brief for over a quarter of a century on subjects like comparative animal cognition and evolution allows you to watch a great deal of water flow under the bridge. Fashions come and fashions go - specifically, perspectives on the similarity - or otherwise - of human and ape minds.

I remember the first Horizon science documentary about the chimpanzee Washoe, the great ape communicator, using American Sign Language to bridge the species barrier. And, later, Kanzi the bonobo jabbing his lexicon. These were the apes, as Sue Savage-Rumbaugh has put it, that were "on the brink of the human mind".

I remember when the pre-print of Machiavellian Intelligence, by Andrew Whiten and Dick Byrne, plopped onto the doormat of the BBC Antenna science series office in 1988. Suddenly primatology had become a great deal more exciting. Could primates, and especially higher primates like chimpanzees, really be as full of guile, as dastardly, as cunning, and as manipulative as the eponymous Florentine politician? Could they really reach deep into the minds of other individuals to see what they believed and what they wanted, and turn that information into deception?

I remember discussing primate cognition with a young Danny Povinelli, as we sat finger-feeding ourselves shrimp gumbo and new potatoes out of plastic Tupperware containers in a Lafayette restaurant surrounded by an alligator-infested moat, before returning to his kingdom - the New Iberia Research Centre - where the University of Louisiana had lured him back to his native deep South by turning a chimpanzee breeding centre for medical laboratory fodder into a primate cognition laboratory with one of the largest groups of captive chimpanzees in the country. He looked like a kid who had just been thrown the keys to the tuck shop.

In those days Povinelli shared the zeitgeist - spread by Whiten's and Byrne's work, and started by Nick Humphrey and Alison Jolly before them - that, since the most exacting and potentially treacherous environment faced by chimpanzees and other primates was not physical, but the social environment of their peers, they had evolved a form of social cognition very much like our own, in order to deal with it. This was further elaborated into a full-blown "social brain" hypothesis by Robin Dunbar, who related brain neocortex size to social group size throughout the primates and up to man. Povinelli's early work reflects this optimism for the mental life of apes, but both ape-language and ape-cognition research was subjected to a cold douche of searching criticism during the 1990s, and misgivings set in regarding the effectiveness of the experiments that had been constructed to guage ape cognition. Now the worm has turned again, with a number of research groups emerging with bolder and bolder claims for the Machiavellian machinations of primate minds, only to be powerfully countered by the curmudgeonly skepticism, chiefly by Povinelli, that these researchers are merely projecting their mental life onto that of their subjects; that, rather in the frustrating manner of Zeno's arrow that could never quite reach its target because it continually halved its distance to it, no experiment constructed thus far can actually get inside the mind of a chimp and show us exactly what it does and doesn't know, or how much, about the minds of others or the way the physical world works. One influential part of the world of comparative animal cognition talks of a continuum between ape and human minds and shrinks the cognitive distance between us and chimps to almost negligible proportions, while another returns us to the unfashionable idea that human cognition is unique, among the primates, after all.

When I began writing this book the working title was "The 1.6% that makes us human". My aim had always been to scrutinize the impression put about in the popular science media that humans and chimps differ by a mere 1.6% in our genetic code - or even less - and that it therefore makes complete sense that this minuscule genetic difference translates into equally small differences in cognition and behaviour between apes and man. However, contemporary genome science and technology, over the last few years, have dramatically advanced the power and resolution with which scientists can investigate genomes, eclipsing the earlier days of genomic investigation that gave rise to the "1.6% mantra".

As with comparative cognitive studies, conclusions on chimp-human similarity and difference in genome research depend crucially on perspective. To look at the complete set of human chromosomes, side by side with chimpanzee chromosomes, at the level of resolution of a powerful light microscope, for instance, is to be overwhelmed by the similarity between them. Overwhelmed with a sense of how close our kinship is with the other great apes. True, our chromosome 2 is a combination of two chimp chromosomes - giving humans a complement of 23 chromosome pairs to 24 in chimps, gorillas and orang-utans - but even here you can see exactly where the two chimp chromosomes have fused to produce one. The banding patterns you visualize by staining the chromosomes match up with astonishing similarity - and that banding similarity extends to many of the other chromosomes in the two genomes. However, look at a recent map of the chromosomes of chimps and humans, aligned side by side, produced by researchers who have mapped all inversions - end-on-end flips of large chunks of DNA - and the chromosomes are all but blotted out by a blizzard of red lines denoting inverted sequence. Now you become overwhelmed by how much structural change has occurred between the two genomes in just 6 million years. True, not all inversions result in changes in the working of genes - but many do - and inversions might even have been responsible for the initial divergence of chimp ancestor from human ancestor.

The extent to which you estimate the difference between chimp and human genomes depends entirely on where you look and how deeply. Modern genomics technology has led us deep into the mine that is the genome and has uncovered an extraordinary range of genetic mechanisms, many of which have one thing in common. They operate to promote variability - they amplify differences between individuals in one species. We now know, for instance, that each human is less genetically identical to anyone else than we thought only three years ago. When we compare human genomes to chimpanzee genomes these mechanisms magnify genetic distance still further. I have tried, in this book, to follow in the footsteps of these genome scientists as they dig deeper and deeper into the "Aladdin's Cave" of the genome. At times the going gets difficult. Scientists, like any explorers, are prone to taking wrong turnings, getting trapped in thickets, and covering hard ground, before breaking through into new insights. I hope that those of you who recoil from genetics with all the visceral horror with which many regard the sport of pot-holing will steel yourselves and follow me as far as I have dared to go into Aladdin's Cave. For only then will you see the riches within and begin to appreciate, as I have, just how limited popular accounts of human-chimpanzee genetic difference really are. Let me try and persuade you that this is a journey, if a little arduous at times, that is well worth taking.

There are a number of scientists around the world who have the breadth and the vision to have begun the task of rolling genetics, comparative animal cognition, and neuroscience into a comprehensive new approach to the study of human nature and this is part, at least, of their story. They strive to describe the nature of humans in terms of the extent to which we are genuinely different to chimpanzees and the other great apes. Somehow, over 6 million years, we humans evolved from something that probably resembled a chimpanzee (though we cannot yet be entirely sure) and the answer to our evolution has to lie in a growing number of structural changes in our genome, versus that of the chimpanzee, that have led to the evolution of a large number of genes that have, effectively, re-designed our brains and led to our advanced and peculiar human cognition.

If you don't believe me, hand this book to your nearest friendly chimpanzee and see what he makes of it!

Tuesday, 29 December 2009

Chimps Use Cleavers And Anvils As Tools To Chop Food

Interesting piece about the observations of Kathelijne Koops, together with Bill McGrew and Tetsuro Matzuzawa, on novel tool use of the chimps in the Nimba Mountains of Guinea. Because the Treculia fruits they are so fond of are very large - the size of a volleyball and weighing up to 8.5 kilos - they cannot access the food by biting into it. They use a variety of stone and wooden cleavers to splinter the fruit into manageable pieces on stone anvils. The practice is very local to this group of chimps - a local culture - and is not shared, for example, by the neighbouring Seringbara chimps.

When Fire Approaches, Chimps Keep Their Cool

Interesting article in SCIENCENOW about the work of primatologist Jill Pruetz with the Fongoli chimps, regarding their behaviour toward fire. Instead of panicking and totally failing to comprehend the nature of fire, she noted that the chimps reacted to brush fires by carefully forging paths to avoid the outbreaks. If you allow that human mastership of fire required three stages: conceptualizing it (meaning also to lose fear of it); starting it; and containing it, Preutz argues, you can see chimp behaviour, perhaps, as a clue as to how some putative hominin ancestors reacted to fire, which eventually led to employing fire to cook food etc. I always have a problem with "chimps give clues to origins of human behaviour" stories because we did not evolve from them. So, if the logic is defensible it is only by virtue of arguing that chimps retained some vestige of loss of fear of fire that was present in the common ancestor of chimps and humans.

Microcephaly Genes Associated With Human Brain Size.

In the third chapter of NOT A CHIMP I explain that Bruce Lahn's "quick and dirty" route to human brain evolution, based on the recent selection of variants for two genes associated with microcephaly, foundered because a number of research groups around the world, including his own, could find no links between variants of these genes and measurements of brain size in modern populations. However, this group has found a new and much more accurate way of measuring cortical surface area and they report significant associations between C.S.A. and variants of the CDK5RAP2 gene involving changes to its regulatory region. They conclude: "One particularly interesting feature of this new discovery is that the stronger links with cortical area were found in regulatory regions, rather than in the coding regions of the genes. One upshot of this may be that in order to further understand the molecular and evolutionary processes that have determined human brain size, we need to focus on regulatory processes rather than further functional characterization (changes in amino-acid sequence) of the proteins of these genes. This has huge implications for future research on the links between genetics and brain morphology."

This group did not, it appears, attempt to discover the age of the evolution of the regulatory variants they examined but it will be very interesting if they choose to investigate ASPM and Microcephalin, the two genes Lahn worked on and which tipped him into hot political water!

Does Culture Prevent Or Drive Human Evolution?

In the penultimate chapter of NOT A CHIMP I argue the case for accelerated recent human evolution, including the claim, from genome-wide trawls for signatures of selection, that as much as 10% of the human genome has undergone evolution within the last 40,000 years or less. In other words, that human demographic and cultural movement into new latitudes and geographical parts of the earth, allied to innovations such as villages and, eventually, conurbations; agriculture; and technology, have imposed a totally new set of selection pressures on human populations. A scenario in which gene-culture interactions become predominant. Here, molecular anthropologist Mark Stoneking, debates the idea, sympathetically, in a recent essay. The comments that follow are also essential reading.

The Looming Crisis In Human Genetics

Just spotted this November-dated essay in The Economist from my friend Geoffrey Miller. He provocatively claims that the crisis (for liberals) will arise in 2010 because GWAS (genome wide association studies) will turn out to tell us less about the genetic causes of mankind's diseases than the genetic variants and associations that underpin widespread genetic variation across races, ethnicities and regions. More trouble for "all men were created equal" ideologues. As Miller concludes: "If the shift from GWAS to sequencing studies finds evidence of such politically and morally perplexing facts, we can expect the usual range of ideological reactions, including nationalistic retro-racism from conservatives and outraged denial from blank-slate liberals. The few who really understand the genetics will gain a more enlightened, live-and-let-live recognition of the biodiversity within our extraordinary species - including a clearer view of likely comparative advantages between the world's different economies." Miller cites the work by Greg Cochran and Henry Harpending (which, together with work they have published in cahoots with John Hawks and Robert Moyzis) is amply referred to in the penultimate chapter of Not A Chimp - that some human groups have experienced a vastly accelerated rate of evolutionary change within the last 10,000 years - whereas others have not.

Symbolic Gestures And Spoken Language Processed By Common Neural System

Back in the saddle after the Christmas break and catching up on a few interesting items. This PNAS paper, which includes Pat Gannon as an author, compares the areas of the human brain that light up when the subject is presented with symbolic gestures, like pantomimes of actions like threading a needle, or emblems that have social significance like finger to lips to indicate "be quiet", with the speech equivalents. Both classes of stimuli, they report, activate a common left-lateralized network of perisylvian areas of temporal lobe. Their abstract concludes thus: "We suggest that these anterior and posterior perisylvian areas, identified since the 19th century as the core of the brain's language system, are not in fact committed to language processing, but may function as a modality-independent semiotic system that plays a broader role in human communication, linking meaning with symbols whether these are words, gestures, images, sounds or objects."