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!

Wednesday, 14 April 2010

Disruption Of Temporoparietal Junction Affects Moral Judgements

In my chapter INSIDE THE BRAIN I mention the work of Rebecca Saxe and her belief that an area of the brain known as the temporoparietal junction was extremely important in the capacity to infer mental states - beliefs, desires etc. - in other people and thus tremendously important to our ability to form moral judgements that depend on our assessment of others' mental states. In this paper, together with Marc Hauser and others, she reports that, when the TPJ was disrupted using transcranial magnetic stimulation, subjects were much less able to make moral distinctions between intentional versus accidental harm. They judged attempted harms as less morally forbidden and more morally permissable than control individuals.

Tuesday, 13 April 2010

Empathy And Violence Have Similar Circuits In The Brain

During my various stumps around the country giving talks to various branches of Cafe Scientifique I often refer to the inordinate evolution of parts of the brain in humans that we associate with social intelligence and I'm often asked, at question time, why, if we have evolved greater propensities than apes for social intelligence, tolerance, culture etc. etc. are we also capable of our own extremes of violence? Part of the answer might come from this Physorg article which suggests that key components of the social brain, involved in empathy - like the prefrontal and temporal cortices, the amygdala, insula and cingulate cortex - overlap in a surprising way to those circuits that regulate violence and aggression. Whomever translated the article from the original Spanish did a poor job - resulting in some amusing mistakes, and the researchers' own conclusions, that this may help train brains to be more empathic, are just plain silly. Nevertheless, the piece is probably worth noting.

Changes In DNA Sequences That Do Not Produce Protein Are Important For Human Brain Evolution

In my chapter THE RIDDLE OF THE 1.6% I present plenty of evidence that evolutionary changes to parts of the genome that regulate gene expression (rather than DNA sequence change inside those genes) has an important role to play in human evolution, particularly of the brain and cognition. And this fact - beautifully, and recently, established by Ralph Haygood and colleagues, explains why two species - humans and chimps - that differ so little at the level of DNA sequence can be so different over many parameters. Now this same team have taken another wide-angle look at the human genome and have established strong correlations between evolution of non-coding regulatory sequences of DNA and gene expression "indicating that neural development and function have adapted mainly through non-coding changes...whereas adaptation via coding changes (evolution inside genes) is dominated by immunity, olfaction and male reproduction."

Genes that are highly tissue-specific in terms of where they are expressed are more likely to undergo sequence evolution than genes more widely expressed in several tissues. The authors suggest that, since genes work in teams such that any one gene may affect various aspects of the phenotype of an organism (this is called pliotropy) this constrains sequence evolution in genes (potentially throwing a spanner into complex machinery) in favour of gene expression changes. They conclude: "Our findings underscore the probable importance of non-coding changes in the evolution of human traits, particularly cognitive traits."

First Direct Evidence Of Mirror Neurons In Human Brains

In my chapter INSIDE THE BRAIN I mention the fact that the presence of mirror neurons in human brains is hotly disputed in some quarters because of the lack of the sort of direct evidence from probes into the brain that has been garnered from monkeys. Researchers looking at human brains have had to use non-invasive techniques to infer the action of mirror neurons. However, as this report shows, if you have access to deep-implanted electrodes put into human brains to help treat conditions like Parkinsons and epilepsy, you can "piggyback" mirror neuron research. And then you find them...Here's the physorg article in entirety:

"Mirror neurons, many say, are what make us human. They are the cells in the brain that fire not only when we perform a particular action but also when we watch someone else perform that same action.

Neuroscientists believe this "mirroring" is the mechanism by which we can "read" the minds of others and empathize with them. It's how we "feel" someone's pain, how we discern a grimace from a grin, a smirk from a smile.

Problem was, there was no proof that mirror neurons existed — only suspicion and indirect evidence. Now, reporting in the April edition of the journal Current Biology, Dr. Itzhak Fried, a UCLA professor of neurosurgery and of psychiatry and biobehavioral sciences, Roy Mukamel, a postdoctoral fellow in Fried's lab, and their colleagues have for the first time made a direct recording of mirror neurons in the human brain.

The researchers recorded both single cells and multiple-cell activity, not only in motor regions of the brain where mirror neurons were thought to exist but also in regions involved in vision and in memory.

Further, they showed that specific subsets of mirror cells increased their activity during the execution of an action but decreased their activity when an action was only being observed.

"We hypothesize that the decreased activity from the cells when observing an action may be to inhibit the observer from automatically performing that same action," said Mukamel, the study's lead author. "Furthermore, this subset of mirror neurons may help us distinguish the actions of other people from our own actions."

The researchers drew their data directly from the brains of 21 patients who were being treated at Ronald Reagan UCLA Medical Center for intractable epilepsy. The patients had been implanted with intracranial depth electrodes to identify seizure foci for potential surgical treatment. Electrode location was based solely on clinical criteria; the researchers, with the patients' consent, used the same electrodes to "piggyback" their research.

The experiment included three parts: facial expressions, grasping and a control experiment. Activity from a total of 1,177 neurons in the 21 patients was recorded as the patients both observed and performed grasping actions and facial gestures. In the observation phase, the patients observed various actions presented on a laptop computer. In the activity phase, the subjects were asked to perform an action based on a visually presented word. In the control task, the same words were presented and the patients were instructed not to execute the action.

The researchers found that the neurons fired or showed their greatest activity both when the individual performed a task and when they observed a task. The mirror neurons making the responses were located in the medial frontal cortex and medial temporal cortex, two neural systems where mirroring responses at the single-cell level had not been previously recorded, not even in monkeys.

This new finding demonstrates that mirror neurons are located in more areas of the human brain than previously thought. Given that different brain areas implement different functions — in this case, the medial frontal cortex for movement selection and the medial temporal cortex for memory — the finding also suggests that mirror neurons provide a complex and rich mirroring of the actions of other people.

Because mirror neurons fire both when an individual performs an action and when one watches another individual perform that same action, it's thought this "mirroring" is the neural mechanism by which the actions, intentions and emotions of other people can be automatically understood.

"The study suggests that the distribution of these unique cells linking the activity of the self with that of others is wider than previously believed," said Fried, the study's senior author and director of the UCLA Epilepsy Surgery Program.

"It's also suspected that dysfunction of these mirror cells might be involved in disorders such as autism, where the clinical signs can include difficulties with verbal and nonverbal communication, imitation and having empathy for others," Mukamel said. "So gaining a better understanding of the mirror neuron system might help devise strategies for treatment of this disorder."

Provided by University of California - Los Angeles