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!

Friday, 29 May 2009

Human FOXP2 "Knock-in" Mice

In chapter 2 of NOT A CHIMP I report that Wolfgang Enard, at the Max Planck Institute for Evolutionary Anthropology in Leipzig, was about to do experiments where the human version of the FOXP2 "language gene" has been "knocked in" to mice. The human FOXP2 protein differs from the version in chimps by two amino-acid substitutions. Interestingly they now report, in the May 29th edition of Cell, that the "mice with the human FOXP2 show changes in brain circuits that have been previously linked to human speech. Intriguingly enough, the genetically altered mouse pups also have qualitative differences in ultrasonic vocalizations they use when placed outside the comfort of their mothers' nests". Enard's "knock in" research nicely mimics Joseph Buxbaum's "knock out" research, reported in my book, where he knocked out the murine FOXP2 from mice and noticed severe developmental abnormalities when both copies of the gene were knocked out, but when only one copy was removed the pups failed to produce the same ultrasonic distress calls noted by Enard. Physorg reports Enard's group as saying: "Since patients that carry one nonfunctional FOXP2 allele show impairments in the timing and sequencing of orofacial movements, one possibility is that the amino acid substitutions in FOXP2 contributed to an increased fine-tuning of motor control necessary for articulation, i.e. the unique human capacity to learn and coordinate the muscle movements in lungs, larynx, tongue and lips that are necessary for speech."

Stretching Your Mouth Affects What You Hear

In my chapter INSIDE THE BRAIN I explain how the operation of certain mirror neurons in turning perception of speech in others into your own speech production was, in effect, a demonstration of the so-called motor theory of speech. Here, in this Scientific American piece, is a fascinating bit of support for this theory from David Ostry, a neuroscientist from McGill University, Montreal. Ostry used a robotic device to pull and tug areas around the mouth when volunteers synchronously heard speech sounds. So, for instance, when the volunteer heard a speech sound that could have been "head" or had" he was more likely to interpret that sound as "head" if his mouth was stretched upwards slightly toward the position he would use if he were saying the word "head". Ostry's work not only supports the idea that we use mirror neurons to learn how to speak by monitoring others' speech and reproducing those sounds for ourselves, it supports the idea that speech and language and speech production use the same motor circuits in the brain. This might help us to understand why the speech impediments in the KE family, which I report in Chapter 2 of NOT A CHIMP, are also associated with certain grammar deficits.

Wednesday, 27 May 2009

Mirror Neuron Theory Under Fire

I deal with mirror neurons in my chapter Inside The Brain, and slid in a short mention that not everyone in the world of neuroscience is a firm believer that mirror neurons exist and are the fundamental plank of much social cognition. Here New Scientist reports the work of Alfonso Caramazza, of Harvard University, who argues that neurons should adapt to repeated stimulation by reducing successive responses. If mirror neurons, which are said to fire both when you observe an action in the outside world and when you perform the similar action (a hand gesture for instance) for yourself, really do exist they should adapt therefore to both observation and performance - but they do not. He found only that they adapted when gestures were observed then enacted, but not the other way round. Mirror neuron afficionado Marco Iacoboni, however, is not impressed, claiming that mirror neurons are different to most classes of neurons in that they do not adapt. This would seem to be a space to watch. Mirror neuron skepticism is not going to go away.

Rooks Make and Use Tools

Rooks are not observed using tools in the wild, which makes this discovery by Nathan Emery and the appropriately named Christopher Bird (see my chapter Clever Corvids) all the more interesting because they prove to be adept tool users and makers in the laboratory setting. We need an explanation for this "latent" form of cognition. As the BBC article explains, they perform on first trial without intensive learning. They prove able to select an appropriate stone for diameter to push into a tube to release a trap-door and thus the food, and they fashion appropriate hooks from straight pieces of metal to fish for food in a bucket in a perspex well. They have also been seen to make tools involving two steps. This is immensely important because it means that the rooks are not operating under some simple behavioural rule which rewards with instant gratification but can use a tool to make a tool to get the reward - a much more impressive feat. This is called metatool use and was previously thought to be unique to hominins. Rooks have now joined New Caledonian crows as the master tool-makers of the animal world showing, again, that big-brained corvids are a match for chimps in this area at least. You can find he abstract to their paper in PNAS at

Tuesday, 26 May 2009

The Oxytocin Receptor and Human Altruism

In "Not A Chimp" I explain how vasopressin, specifically the activity of variants of the vasopressin receptor gene in the brain, relate to monogamy, pair-bonding, social affiliation and altruism. Now the same research group involved in the vasopressin-altruism research, led by Richard Ebstein of the Hebrew University, Jerusalem, have extended their work, using the Dictator Game as a proxy for altruism, to the other half of the "cuddle" hormone duo - oxytocin. How generous you are to your partner on the game relates to whether you are prosocial, proself, or ruthlessly selfish. They discovered a number of polymorphisms of the oxytocin receptor gene that were strongly associated with prosocial, altruistic behaviour. This list of gene variants strongly associated with human variation for different aspects of social behaviour is growing all the time!

Musical Aptitude linked to Vasopressin Receptor Gene Variants

In the penultimate chapter of "Not A Chimp" I fashion the beginnings of a biosocial science to human nature founded on genetic variants for a number of neurotransmitters and hormones including dopamine, serotonin and vasopressin. Here a group from Finland look at the same variants of the vasopressin receptor gene avpr1a that had been previously linked to ability for creative dance by Rachel Bachner-Melman. They have shown that aptitude for structuring music, time and pitch are all significantly associated with certain of these variants. Although it's difficult to pin down, they say, the precise selective advantage to humans of musical ability, it is clearly a social exercise, might make you attractive to the opposite sex, and is an important element of group cohesion and collective ritual. We have to be a bit careful of these results because the scores for the various aspects of musical ability were compiled from Internet questionnaires and there is always the possibility of self-reporting bias creeping in. Nevertheless, a nice addition to this burgeoning field.