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embodied cognition: common sense or something startling? – part two. language and education

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Canto: There isn’t much detail in Lobel’s book about how sensations or the senses can be harnessed to education, but she tantalisingly offers this:

Several studies have shown that peppermint and cinnamon scents improved cognitive performance, including attention and memory; clerical tasks, such as typing speed and alphabetisation; and performance in video games.

Jacinta: Right, so we spray peppermint and cinnamon about the classroom, and genius rises. But is there anything in this approach specifically for language learning?

Canto: Well, a key insight, if you can call it that, of embodied cognition is that not only does the mind influence the body’s movements, but the body influences our thinking. And the relationship can be quite subtle. It’s known from neurophysiological studies that a person’s motor system is activated when they process action verbs, and when they observe the movements of others.

Jacinta: So that’s about mirror neurons?

Canto: Exactly. The basic take-away from this is that activating mirror neurons enhances learning. So as a teacher, combining gestures, or ‘acting out’ with speech to introduce new language, especially verbs, is an effective tool.

Jacinta: Playing charades, so that students embody the activity? This can be done with phrasal verbs, for example, which students often don’t get. Or prepositions. The teacher or students can act them out, or manipulate blocks to show ‘between’ ‘next to’, ‘in front of’, ‘under’, etc. This would be a useful strategy for low-level learning at our college, really engaging the students, but it would also help with higher level students, who are expected to write quite abstract stuff, but often don’t have the physical grounding of the target language, so they often come out with strange locutions which convey a lack of that physical sense of English that native speakers have.

Canto: Yes, they use transition signals and contrast terms wrongly, because they’re still vague as to their meaning. Acting out some of those terms could be quite useful. For example, ‘on the one hand/on the other hand’. You could act this out by balancing something on one hand, and then something of equal weight on the other hand, and speaking of equal weights and balancing in argument, and then getting the students to act this out for themselves, especially those students you know are likely to misconstrue the concept. ‘Furthermore’ could be acted out both by physically adding more to an argument and taking it further in one direction. ‘Moreover’ takes more over to one side. You could use blocks or counters to represent contrast words, a word or counter that shifts the argument to the opposite side, and to represent the additive words, with counters that accumulate the arguments on one side.

Jacinta: So this acting out, and gesturing, all this is very suggestive of the origins of language, which might’ve begun in gestures?

Canto: Yes it’s a very complex communicative system, which may well have begun with a complex gestural system, accompanied by vocalisations. Think of the complexity of signing systems for the deaf – it’s extraordinary how much we can convey through hand gestures accompanied by facial expressions and vocalisations, or even partial vocalisations or pre-vocalisations – lip movements and such. Other primates have complex gestural communisation, and it was in monkeys that mirror neurons were first discovered by neurophysiologists examining inputs into the motor cortex. They are the key to our understanding of the embodied nature of language and communication. When we learn our L1, as children, we learn it largely unconsciously from our parents and those close to us, by copying – and not only copying words, but gestures which accompany words. We absorb the physical framing of the language, the tone in which certain words are conveyed, words and phrases – locutions – associated with physical actions and feelings such as anger, sadness, humour, fear etc, and they fire up or activate neurons in the motor cortex as well as in those centres related to language processing.

Jacinta: I’ve heard, though, that there’s a competing theory about the origin and evolution of language, relating to calls, such as those made by birds and other animals.

Canto: Not just one other. This has been described as the hardest problem in science by some, and I’ve hardly scratched the surface of it, but I recently watched an interview with Giacomo Rizzolatti, whose team discovered mirror neurons in monkeys, and he strongly favours the gestural origin theory, though he also says we need more neurophysiological evidence, for example of mirror neurons in other areas of the brain, or the absence of them, before we decide once and for all. He finds the debate a little ideological at present.

Jacinta: Well the origin of language obviously involves evolution, but there are few traces discoverable from the past. Spoken language leaves no trace. So it’s always going to be highly speculative.

Canto: Well it may not always be, but it long has been that’s for sure. Apparently the Linguistic Society of Paris banned all present and future debate on the origins of language back in 1866, so we could get arrested for this post.

Jacinta: Yeah, a bit hard to enforce that one. So we have no idea about when human language evolved, or did it evolve gradually over hundreds of thousands of years?

Canto: Well, that’s more speculation, but there are continuity theories (language is this extremely complex thing that came together gradually with the accumulation of changes – mutations or brain-wirings – over an extended period), and there are discontinuity theories that favour, for example, a single transformative genetic mutation.

Jacinta: And what about the song theory – that’s one I’ve heard. That song, and therefore music, preceded language. I suppose that’s romantic speculation – right up our alley.

Canto: Okay so this is very interesting and something to follow up in future posts, but we should get back to our main subject, the implications of embodied cognition for language learning today.

Jacinta: Aren’t the implications fairly straightforward – that we learned language, that’s to say our L1 – in a thoroughly embodied way, within a rich sensory and physical context, as highly active kids, and so it’s a battle to get students to learn their L2 or another language, because neurons that fire together wire together, and there’s this thing called brain frugality which makes us always look for short-cuts, so we always want to convert the L2 into the familiar, wired-in L1, rather than trying to grasp the flow of a foreign language. We want to work in the familiar, activated channels of our L1. So, as teachers, we can help students to develop channels for their L2 by teaching in a more embodied way.

Canto: Here’s a thought – I wonder if we can measure teaching techniques for L2 by examining the active brain and the feedback mechanisms operating between cortices as students are being taught? Have we reached that level of sophistication?

Jacinta: I doubt it. It’s an intriguing thought though. But what exactly would we be measuring? How much of the brain is ‘lighting up’? How long it’s remaining lit up? And how would we know if what’s being activated is due to language learning? It could be active avoidance of language learning…

Canto: I need to learn much more about this subject. I’ve heard that you can’t and shouldn’t teach an L2 in the way we learn our L1, but what does that mean? In any case, it’s true that the way we teach, in serried rows, facing the front with too much teacher talk and a general discouragement of talking out of turn and even moving too much, it really does smack of an old dualist conception, with disembodied minds soaking up the new language from the teacher.

Jacinta: Well surely you don’t teach that way any more, shame on you if you do, but there are ways in which a more embodied approach can be used, with role-playing, framing and other forms of contextualising.

Canto: Yes, clearly contextualising and incorporating action, sensation and emotion into language teaching is the key, and getting students to use the language as often as possible, to learn to manipulate it, even if ungrammatically at times and with gestural accompaniment….

Jacinta: So, like learning L1? But we ‘pick up’ our L1, we absorb it like little sponges, together with context and connotation. Is that really how to learn an L2? Is the idea to replace the L1 with a thoroughly embodied L2? Or is it to have two – or more – fully embodied, firing-and-wired transmitting and feedback-looping  language systems alongside each other. What about energy conservation?

Canto: Okay so let this be an introductory post. I clearly need to research and think on this subject a lot more…

the brave new world of neurophenomenology, apparently

the brave new world of neurophenomenology, apparently

 

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Written by stewart henderson

January 22, 2017 at 9:50 pm

why are our brains shrinking?

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my own brain, squeezed of alcohol

my own brain, squeezed of alcohol

Jacinta: So you know that the average human brain mass, or is it volume, has reduced by  – is it 15%, I can’t remember – over the past 20,000 years or so, right? And there’s this theory that it’s somehow related to domestication, because the same thing has happened to domesticated animals…

Canto: How so..?

Jacinta: Well, we don’t know how so, we just know it’s happened.

Canto: How do we know this? Who says?

Jacinta: Well I’ve heard about it from a few sources but most recently from Bruce Hood, the well-known psychologist and skeptic who was talking on the SGU about a recent book of his, The Domesticated Brain. 

Canto: So the idea is that humans have somehow domesticated themselves, in the same way that they’ve domesticated other species, with a corresponding decrease in brain mass in all these species, which signifies – what?

Jacinta: Well it raises questions, dunnit? What’s going on?

Canto: It doesn’t signify dumbing down though – I read in Pinker’s big book about our better angels that our average IQ is rising in quite regular and exemplary fashion.

Jacinta: Yes, the Flynn effect. Though of course what IQ measures has always been controversial. And they do reckon size isn’t the main thing. I mean look at all those small critters that display so many smarts. For example, rats, octopuses and corvids (that’s to say crows, ravens and some magpies). They all seem to be fast learners, within their limited spheres, and very adaptable. But getting back to the human brain, it seems to be something known mainly to palaeontologists, who have a variety of theories about it, including the ‘we’re getting dumber’ theory, but I’m not convinced by that one. It seems more likely that our brains are getting more organised, requiring less mass.

Canto: So this has happened only in the last 20,000 years?

Jacinta: Or perhaps even less – between 10 and 20 thousand.

Canto: Isn’t that a phenomenally short time for such a substantial change?

Jacinta: I really don’t know. They say it might be partly related to a decrease in overall body size, so that the brain to body ratio remains much the same.

Canto: A decrease in body size? What about the obesity epidemic? And I remember way back when I was a kid reading about how we’d been getting taller with each generation since the Great Depression – or was it the Industrial Revolution? Anyway our improved diet, our era of relative abundance, has led to a change in height, and presumably in mass, in only a few generations.

Jacinta: So now you’re saying that substantial changes can occur in a few generations, let alone 10,000 years?

Canto: Uhhh, yeah, okay, but I wasn’t talking about brain size.

Jacinta: Well why not brain size? Anyway, although there have been those recent changes, at least in the west, the story goes that the planet has warmed since the last ice age, favouring less bulky bodies, less fat storage, more gracile frames.

Canto: So what about domestication, why has this led to decreased brain sizes?

Jacinta: Well this is very complex of course…

Canto: I can think of a reason, though it might not be called domestication, more like socialisation, and outsourcing. You can see it in very recent times, with smart phones – it’s even become an already-stale joke, you know phones are getting smarter so we’re getting dumber. But then we always tend to exaggerate the short-term and the present against the longer view. And yet…. I was on the tram the other night, sitting across from this couple, locked into their phone screens, I mean really locked in, earplugs attached, heads bent, utterly fixated on their little screens, completely oblivious, of each other as well as of the outside world. I was reading a book myself, but I became distracted by my irritation with these characters, while wondering why I should be irritated. It just went on so long, this locked-in state. I leaned forward. I waved my hand in front of their bowed heads. I wanted to tell them that the tram had rattled past all the stations and was heading out to sea…

Jacinta: There are some problems with the whole argument. How do we know that domesticated animals have smaller brains? Domesticated cats have a wide range of brain sizes no doubt, but what wild cats are you comparing them with? Even more so with dogs and their immense varieties. Okay they’re descended from wolves so you compare a wolf brain with its modern doggy-wolfy counterpart, but who’s going to agree on type specimens?

Canto: So you brought the subject up just to dismiss it as a load of rubbish?

Jacinta: Well if we shelve the domestication hypothesis for the moment – I’m not dismissing it entirely – we might consider other reasons why human brains are shrinking – if they are.

Canto: So you’re not convinced that they are?

Jacinta: Well let’s be sceptical until we find some solid evidence. In this Scientific American site, from November 2014, palaeontologist Chris Stringer states that ‘skeletal evidence from every inhabited continent’ suggests – only suggests – that our brains have become smaller in the past 10 to 20 thousand years. No references are given, but the article assumes this is a fact. This piece from Discovery channel or something, which dates back to 2010, relies in part on the work of another palaeontologist, John Hawks, whose website we link to here. Hawks also talks about a bucketload of evidence, but again no references. The original research papers would likely be behind a paywall anyway, and barely intelligible to my dilettante brain….

Canto: Your diminishing brain.

Jacinta: Okay I’m prepared to believe Hawks about our incredible shrinking brains, but is domestication the cause, and what exactly is domestication anyway? Hawks doesn’t go with the domestication hypothesis. In fact the Discovery article usefully covers a number of alternative hypotheses, and of course the shrinking may be due to a combo. In fact that’s more than likely.

Canto: So what’s Hawks’ hypothesis, since we’re supposedly admirers of his?

Jacinta: Well Hawks decided to look more closely at this brain contraction – which is interesting because I was thinking along the same lines as he was, i.e. has it been a uniform contraction, or was there a sudden, quick development, followed by a stagnant period, as you would expect?

Canto: Anyway isn’t brain organisation more important than brain mass? Sorry to interrupt, but haven’t we already established that?

Jacinta: We haven’t established anything, we’re just effing dilettantes remember. Hawks started looking at more recent data, over the past 4000 years or so, to see if he could detect any difference in the encephalisation quotient (EQ) – the ratio of brain volume to body mass – over that time. He found that indeed there has. The picture is complicated, but overall there has been a reduction in the brain compared to the body. His explanation for this though is quite different. He reckons that a series of mutations over recent history have resulted in the brain producing more out of less…

Canto: Right, just as a series of modifications have allowed us to produce smaller but more powerful and fuel-efficient cars.

Jacinta: Uhh, yeah, something like that.

Canto: But we know what those modifications were, we can name them. Can we name the mutations?

Jacinta: Clever question, but we know about cars, we built them and they’ve only been around for a bit more than a century. We know vastly less about the brain and we’re still getting our heads around natural selection, give us a break. Hawks points out that it’s a rule about population genetics well-known in principle to Darwin, that the larger the population the more numerous the mutations, and there was a surge in the human population back when agriculture was developed and large settlements began to form. So a number of brain-related mutations led to streamlining and, as you suggest, fuel efficiency.

Canto: But isn’t this compatible with the domestication hypothesis? I imagine that, if there really is a brain reduction for domesticated animals, it’s because they don’t have to rely on their brains so much for survival, and we don’t either, the collective has sort of magically taken care of it through farming and infrastructure and supermarkets.

Jacinta: Yes but they all have their own complicated networks and issues we have to wrap our brains around. The domestication hypothesis is really about aggression apparently. The argument goes that all animals under domestication become more varied in size, coloration and general build, with a tendency to become more gracile over all. Selection against aggression, according to the primatologist Richard Wrangham, favours a slowly developing brain – one that is, in a sense, in a perpetually juvenile state (think of cute cat and dog videos). Of course, all this assumes that juvenile brains are less aggressive than adult brains, which some might see as a dubious assumption.

Canto: Yes, think of school bullying, Lord of the Flies, youth gangs, the adolescent tendency to extremes…

Jacinta: Well, both Wrangham and Hood offer a particularly interesting example of ‘super-fast’ domestication to illustrate their hypothesis:

In 1958 the Russian geneticist Dmitri Belyaev started raising silver foxes in captivity, initially selecting to breed only the animals that were the slowest to snarl when a human approached their cage. After about 12 generations, the animals evidenced the first appearance of physical traits associated with domestication, notably a white patch on the forehead. Their tameness increased over time, and a few generations later they were much more like domesticated dogs. They had developed smaller skeletons, white spots on their fur, floppy ears, and curlier tails; their craniums had also changed shape, resulting in less sexual dimorphism, and they had lower levels of aggression overall.

Now, how does this relate to juvenilism? Well, in the wild, offspring grow up quickly and have to fend for themselves, which requires a certain ruthless degree of aggression. Cats and dogs, yes, they abandon their offspring soon enough, but those offspring continue to be tutored, tamed, domesticated under their human owners. We hear a lot about school bullying and gangs of youths, but they’re actually the exception rather than the rule, or a last ditch rebellion against the domestication pressure that’s exerted by the whole of society, and they’ll either succumb to that pressure or end up in jail, or worse. It’s a bit like the Freudian concept of sublimation, you channel your aggressive energies into creativity, competitive problem-solving, sports achievements and the like.

Canto: So you’re in favour of the domestication hypothesis?

Jacinta: Well, I’m not against it. It sounds plausible to me. Human domestication, or self-domestication if you want to call it that, is a social-contract sort of thing. You agree to outsource and comply with certain arrangements – laws, government, taxation and so forth, in return for certain benefits in terms of security and resources. So you don’t have to fend for yourself. And that affects the brain, obviously. Though it might not be the whole story.

Written by stewart henderson

April 15, 2016 at 8:42 am

The philosophers want more power

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tamsin shaw

tamsin shaw

Canto: Well I suppose the apparent detection of gravitational waves should be capturing our attention more than anything else right now, but it’s very well described in The Economist, and in many other places, and we’re no astrophysicists, and we did promise to focus a bit more on philosophical issues, so…

Jacinta: But we’re no philosophers. But we’re philosophasters at least, so let’s have a go.

Canto: Well I came across an article on Three Quarks Daily which vaguely gave me the irrits, so with your help I want to explore why.

Jacinta: Right. The essay is called ‘The psychologists take power’, the author is Tamsin Shaw and it was originally published in the New York review of books.

Canto: Yes, and on reading it in full I find it an interesting but confused piece, which seems to take the failings of certain individual psychologists as an example of the failings of psychology as a whole, and even of neurology. Shaw seems to be entering the philosophy versus science debate, on the side of philosophy, but I don’t find her arguments convincing.

Jacinta: The essay seems to divide into two parts, first a general critique of psychology and neurology, which can be summed up by the title of a philosophical essay by Selim Berker, which she quotes approvingly, ‘the normative insignificance of neuroscience’. The second part is an account of how certain professional psychologists, practitioners of the ‘positive psychology’ pioneered by the influential Martin Seligman, colluded with the US government in providing dubious evidence for the psychological effectiveness of torture in eliciting valuable information from ‘enemies of the state’. Shaw clearly wants to link these unethical practices to what she might want to call ‘the normative insignificance of psychology’.

Canto: Yes, and it’s a bit of a dangerous game – you might as well label Heidegger’s allegiance to the Nazi party, or Althusser’s murder of his wife, as examples of ‘the normative insignificance of philosophy’.

Jacinta: Ha, well Althusser was declared insane at the time, no doubt by psychologists, who would be examining Althusser to determine whether he was, while strangling his wife, capable of understanding and following the normative rules of his society. Such determinations are hardly normatively insignificant, even though, no doubt, individual psychologists might make different determinations, due to levels of competence, corruption, ideological considerations and so forth.

Canto: Right, but let’s look more closely at Shaw’s essay, and pick it apart.

Jacinta: Okay, but first let’s make a philosophasters’ confession. Shaw mentions eight or so books or sources at the head of her essay, which form the basis of her discussion, but of those we’ve only read one – Pinker’s eloquent tome, The better angels of our nature. And we don’t intend to bone up on those other texts, though no doubt we’ll refer to our own reading in our responses.

Canto: And we are reasonably familiar with Jonathan Haidt’s work and ideas.

Jacinta: So Shaw begins her essay with the overweening ambition of behaviourist extraordinaire B F Skinner, a pretty soft target these days. I have no problems with criticising him, or Freud or any other psychologist whose theories get way out of hand. Shaw’s concerns, though, are specifically about the moral sphere. She feels that a new breed of psychologists, armed with neurological research, are making big claims about moral expertise. Here’s a quote from her essay:

Neuroscience, it is claimed, has revealed that our brains operate with a dual system for moral decision-making.

Canto: I like the ‘it is claimed’ bit. Claimed by who? Someone has put forward that hypothesis I’m sure, along with their reasons, but most neurologists bang on about neurology being a field in its infancy, and most findings are highly contested, it seems to me.

Jacinta: Shaw may be referring to the work of Daniel Kahneman – a psychologist not a neurologist – who distinguished between system 1 thinking (intuitive, less conscious, rough-and ready) and system 2 thinking (reasoned, conscious, more changeable depending on inputs and knowledge). But really there are many dual-process theories going back at least to William James. But Shaw is explicitly referring to the fMRI imaging work of the neurologist Jonathan Cohen, who analysed brain activity when subjects were asked to think about moral hypotheticals.

Canto: Yes and she’s quite straight about describing the two systems apparently highlighted by Cohen’s research and the brain regions associated with them, but becomes scathing in dealing with Joshua Greene, Cohen’s co-researcher, whom she quite deliberately introduces as a mere ‘philosophy graduate student’, whose interpretation of the research she describes thus:

Greene interpreted these results in the light of an unverifiable and unfalsifiable story about evolutionary psychology. Since primitive human beings encountered up-close dangers or threats of personal violence, their brains, he speculated, evolved fast and focused responses for dealing with such perils. The impersonal violence that threatens humans in more sophisticated societies does not trigger the same kind of affective response, so it allows for slower, more cognitive processes of moral deliberation that weigh the relevant consequences of actions. Greene inferred from this that the slower mechanisms we see in the brain are a later development and are superior because morality is properly concerned with impersonal values—for example, justice—to which personal harms and goals such as family loyalty should be irrelevant. He has taken this to be a vindication of a specific, consequentialist philosophical theory of morality: utilitarianism.

Jacinta: Okay, so here’s where psychology – especially evolutionary psychology – first comes under attack. It’s often said to present just so stories, which are necessarily highly speculative, as if they are facts. But I would question whether these speculations, or hypotheses, are unverifiable (forget about falsifiability, a term made popular by Karl Popper but which has come under heavy criticism since, both by scientists and philosophers of science, and I suspect Shaw has simply used it as a ‘double whammy’ to vilify Greene), to me they’re important and useful, and in any case are rarely presented as facts, at least not by the best psychologists.

Canto: So how do you verify this hypothesis, that fast, rough-and-ready responses for dealing with immediate dangers are systematically different from slower, more sophisticated responses that deal with the ‘impersonal violence’, the many restraints, justified or not, on our personal freedoms that we deal with on a daily basis?

Jacinta: Well one obvious way is through neurology, a scientific field still in its infancy as you say. Clearly the system 1 responses would be shared by other complex social mammals, whereas system 2 thinking is much more language-dependent and unique to humans – unless cetaceans have developed complex language, which is far from being out of the question. New techniques for mapping and exploring neural pathways are coming up all the time, as well as non-invasive ways of exploring such pathways in our closest mammalian relatives.

Canto: Good point. So to go to the second part of the above quote, Greene is presented (and I wonder about whether Shaw is fairly or accurately presenting him) as finding system 2 thinking as superior because it deals with more abstract and less personal values, whereas I would prefer to think of this system as a further adaptation, to a human existence that has become more socially complex, systematic and language-based. And in this, I’m apparently in line with the thinking of psychologists Shaw takes aim at:

Many of the psychologists who have taken up the dual-process model claim to be dismissive of philosophical theories, generally. They reject Greene’s inferences about utilitarianism and claim to be restricting themselves to what can be proved scientifically. But in fact all of those I discuss here are making claims about which kinds of moral judgments are good or bad by assessing which are adaptive or maladaptive in relation to a norm of social cooperation. They are thereby relying on an implicit philosophical theory of morality, albeit a much less exacting one than utilitarianism.

Jacinta: But I detect a problem here. You’ve talked about adaptation to the fact of growing social complexity, and the need to co-operate within that complexity. Shaw has written of a ‘norm of social co-operation’, by which she means an ethical norm, because she claims that this is the implicit philosophical theory of morality these psychologists rely on. But that’s not true, they’re not claiming that there’s anything moral about social complexity or social co-operation. We just are more complex, and necessarily more co-operative than our ancestors. So it’s kind of silly to say they’re relying on a less exacting moral philosophy than utilitarianism. It’s not about moral philosophy at all.

Canto: And it gets worse. Shaw claims that this phantom moral ethic of social co-operation is greatly inferior to utilitarianism, so let’s look at that normative theory, which in my view is not so much exacting as impossible. Utilitarianism is basically about the maximising of utility. Act in such a way that your actions maximise utility (act utilitarianism), or create rules that maximise utility (rule utilitarianism). So what’s utility? Nothing that can be measured objectively, or agreed upon. We can replace it with happiness, or pleasure, or well-being, or Aristotle’s eudaemonia, however translated, and the problem is still the same. How do you measure, on a large-scale, social level, things so elusive, intangible and personal?

Jacinta: Yes, and look at how laws change over time, laws for example relating to homosexuality, women’s rights, the protection of minorities, and even business practices, taxation and the like; they’re all about our changing, socially evolving sense of how to co-operate in such a way as to produce the best social outcomes. This can’t be easily bedded down in some fixed normative ethic.

Canto: Yes, Shaw seems to imply that some deep philosophical insight is missing from these psychologists which makes them liable to go off the rails, as the second half of her essay implies, but I’m very doubtful about that. But let’s continue with our analysis:

Rather than adhering to the moral view that we should maximize “utility”—or satisfaction of wants—they are adopting the more minimal, Hobbesian view that our first priority should be to avoid conflict. This minimalist moral worldview is, again, simply presupposed; it is not defended through argument and cannot be substantiated simply by an appeal to scientific facts. And its implications are not altogether appealing.

Jacinta: But surely she’s just assuming that ‘they’ – presumably all the psychologists she doesn’t like, or is it all the psychologists who posit a two-tiered system of decision-making? – take the view that avoidance of conflict is the highest priority.

Canto: Well I must say that Jonathan Haidt seems to take that view, and it’s something I find uncomfortable. So I agree with Shaw that Haidt ‘presupposes that the norm of cooperation should take precedence over the values that divide us’, and that this view is dubious. It’s just that I suspect my own view, that there are values more important than co-operation, is also a ‘presupposition’, though I dislike that word. But more of that later perhaps.

Jacinta: Right, so Shaw refers to the sinister implications of a minimalist Hobbesian worldview, supposedly held by these psychologists. What are they?

Canto: We’ll get there eventually – perhaps. Shaw describes the work of the ‘positive psychology’ movement, stemming from Martin Seligman and practised by Haidt among others, including Steven Pinker, whose book The better angels of our nature was apparently influenced by this movement:

In that extremely influential work Pinker argues that our rational, deliberative modes of evaluation should take precedence over powerful, affective intuitions. But by “rationality” he means specifically “the interchangeability of perspectives and the opportunity the world provides for positive-sum games,” rather than any higher-order philosophical theory. He allows that empathy has played a part in promoting altruism, that “humanitarian reforms are driven in part by an enhanced sensitivity to the experiences of living things and a genuine desire to relieve their suffering.” But nevertheless our “ultimate goal should be policies and norms that become second nature and render empathy unnecessary.”

And here’s where I see another problem. Pinker is here criticised for not subscribing to any ‘higher-order philosophical theory’, but Shaw doesn’t attempt to outline or give examples of such higher-order theories, though she does refer to empathy – an important factor, but one that doesn’t obviously emerge from philosophy.

Jacinta: Right, and we’ve already referred to utilitarianism and its problems. This reminds me that years ago  I read a sort of primer on ethics, I think it was called Moral Philosophy, in which the author devoted chapters to utilitarianism, Kantianism, rights theory and other ethical approaches. In the final chapter he presented his own preferred approach, a sort of neo-Aristotelianism. I was intrigued that he felt we hadn’t made much progress in philosophical ethics in almost 2,500 years.

Canto: Well, his may be a minority view, but it’s doubtful that our changing laws derive from philosophical work on normative ethics, though this may have had an influence. I do think, with Haidt, that there’s a great deal of post-hoc rationalisation going on, though I’m reluctant – very reluctant actually – to embrace the relativism of values. And this brings me to the nub of the matter, IMHO. To go back to an old favourite of mine, Hume: ‘reason is and ought only to be the slave of the passions’. A fairly notorious pronouncement, but I take the passions here to be something very basic – the fundamental drives and instincts, largely unconscious, that characterise us as humans…

Jacinta: But doesn’t Hume break his own is-ought rule here? He says that our passions rule our reason, which may or may not be true, but does it follow that they ought to?

Canto: Please don’t complicate matters. Hume also wrote this, in An Enquiry Concerning the Principles of Morals:

In all determinations of morality, this circumstance of public utility is ever principally in view, and wherever disputes arise, either in philosophy or common life, concerning the bounds of duty, the question cannot, by any means, be decided with greater certainty, than by ascertaining, on any side, the true interests of mankind.

So these true interests of mankind…

Jacinta: Hang on, so there he goes again, gaily bounding over his own is-ought barrier, saying that in order to work out what we ought to do we need – pretty well absolutely – to determine our interests, what in fact makes us human, what we actually are.

Canto: Well, precisely…

Jacinta: Or what we have evolved to become, which might amount to the same thing. So we need to study our evolution, our genes and genetic inheritance, our brain and its inheritance, and adaptive growth, and maybe the physics of our bodies…

our old Scottish mate Davey Hume, doyen of skeptics, whose is-ought distinction has been widely misinterpreted, we suspect

our old Scottish mate Davey Hume, doyen of skeptics, whose is-ought distinction has been widely misinterpreted, we suspect

Canto: So we need neurology, and genetics, and palaeontology, and physics and psychology, all of which contribute to an understanding of what we are. Without them, normative ethics would be empty theorising.

Jacinta: So I suppose you’re going to write a rejoinder to this ‘normative insignificance of neurology’ essay? Something like ‘the insignificance of normative ethics without neurology’?

Canto: Ha, well that would require reading Selim Berker’s essay, which I’m not sure about – so many other things to explore. But I should end this discussion by saying a few words about the second half of Shaw’s article – and I’ll pass over many other points she’s made. This section deals with the collusion of some psychologists, practitioners of the above-mentioned ‘positive psychology’, with the CIA and the US Department of Defence in the commission of torture.

Jacinta: And what exactly is this ‘positive psychology’?

Canto: Well, to explain that would require a large digression. Suffice to say for now that it’s about using psychology to make us more resilient, and in some sense ethically superior, or more benign, humans. Shaw dwells on this at some length, but claims that in spite of much rhetoric, these psychologists can only offer what she calls the bare, Hobbesian ethic of avoidance of strife. However, she herself is unable to point to a more robust, or a deeper, ethic. She presumably believes in one, but she doesn’t enlighten us as to what it might be. And this is very striking because the tale of these psychologists’ collusion with the Bush administration  on torture, and the huge financial gain to them in applying ‘learned helplessness’, a theory of Seligman’s, to the application of torture, is truly shocking.

Jacinta: So it would be a question of what, in their make-up, allowed them to engage in such unethical behaviour, and was it the lack of a deep ethical understanding, beyond ‘bare Hobbesianism’?

Canto: Right, and my answer would be that, although two psychologists took up this lucrative offer to ‘serve the state’, there would have been others who refused, and would any of them, on either side, have made their decision on the basis of some rigorous normative ethic?

Jacinta: I’m quite sure I wouldn’t have colluded with that sort of thing for all the terracotta warriors in China, but I’m also sure it wouldn’t have been for deep philosophical reasons. I just have a kind of visceral revulsion for physical violence and bullying as you know, and I wouldn’t be able to live with myself if I’d facilitated the premeditated cruel and unusual punishment of others. I’m not even sure if it’s about empathy, but it’s not a particularly reasoned position.

Canto: Yes, and so the only way to understand why some people are more prone to do unethical things – actions outside of the ever-changing standards of community ethics – might be to look at individual psychology, and neurology, and genetics, which takes us further away from normative ethics than ever.

Jacinta: Yes, and didn’t we read, in Sam Kean’s The tale of the duelling neurosurgeons, about a poor fellow in his mid-fifties who suddenly started engaging in paedophile acts, something he had never showed any signs of before? A brain scan revealed a large tumour pressing on parts of the brain responsible for higher-order decision-making (to put it over-simplistically). When the tumour was removed he returned to ‘normal’, until some time later he regressed to paedophile acts. A further scan showed they didn’t remove all the tumour and it had regrown. After another more successful operation he was cured and never diddled again. But the consequences of his actions for his victims when ‘not himself’ would have required him to be punished, on a consequentialist ethical view, wouldn’t they?

Canto: Very good point. And yet, and yet… can it be true that we’ve barely gone further in our ethics than the Golden Rule, or Aristotle’s mean between extremes?

Jacinta: We’re animals, don’t forget. Okay we’re animals that have managed to detect waves from space that are a tiny fraction of the diameter of a proton, but we’re still not that good at being nice to each other. And the extent to which we’re able to be nice to each other, and follow social norms, that’s a matter of our individual psychology, our neurology, our individual and cultural circumstances, our genes and our epigenetic profile, so much particular stuff that philosophical ethics, with its generalities, can’t easily deal with.

Written by stewart henderson

February 26, 2016 at 8:37 am

women and men: un discours sans fin

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Angel and Devil

Jacinta: Okay Canto, I rather hesitate to open up this subject, because I can’t see an end to it, but I want you to repeat here something you’ve said to me before about women and power, which goes to differences between men and women, an area subject to endless debate and contestation.

Canto: Ah well, I was considering how political power, in the world, is largely in the hands of men, and what the world would be like if the situation was reversed. It’s my humble opinion that the world would be less violent, more collaborative, and a lot more fun.

Jacinta: Well as a woman I’m obviously pleased to hear you say that, but we do try to look at evidence rather than personal opinion here, so what in the way of evidence leads you to this conclusion?

Canto: Well… where do we begin? Simone de Beauvoir famously wrote that women are made and not born, a highly contestable truism as it seems that women are actually wired differently from men, having less neurons but more connections between neurons, in toto and on average, so the very question of what it means to be a woman, or a man is one we’re unlikely to get to the bottom of, but I’d like to start with bonobos, always a favourite topic of mine. They appear to have diverged from chimpanzees only between a million and two million years ago, and they look very similar to chimps, which is likely why they weren’t identified as a separate species until the 1930s, and the differences seem to be far more social than anatomical. I mean, they share the same sexual dimorphism as chimps, and humans, and yet they’re essentially matriarchal, due it seems to social arrangements rather than individual size and strength. That gives me great hope for humans, especially now that physical size and strength are less relevant than ever as leadership qualities.

Jacinta: Ah, well now I get the fun part – you think a human matriarchal society will turn out to be a gigantic mutual wankfest. But what about civilisation? What about science and technology? Considering that women, regardless of culture or nationality, are more into astrology, fortune-telling, spiritualism, religion, naturopathy, and virtually every other pseudo-science and primitivism you care to mention, than men are.

Canto: Well, you’re talking about statistical differences, but you well know that there are many fine female astrophysicists, neurosurgeons, geneticists, experimental psychologists, whatever. You’re hardly the only female skeptic, even if they’re in a minority. And who knows what would happen if females were in a majority, with a history of being in a majority, with respect to leadership and power? Maybe you’d find then that it was men who were more into pseudo-science, statistically speaking.

Jacinta: True, and that brings me to a study analysed on the Skeptics’ Guide to the Universe recently. I had read, like you, that women, overall, had more white matter (the myelinated connections between neurons) than men – by a large factor, and that men had more grey matter, though this was concentrated around particular areas such as the amygdalae and the hypothalamus. However, in the study referred to, the researchers wanted to find if there were any categorical differences between male and female brains. They looked at 4 data sets of MRI and fMRI scans, checking out anatomical and connectional or networking differences, to make comparisons. According to SGU’s Steven Novella (a practising neurologist), the media over-simplified the findings as saying there were no differences, but in fact it was more interesting than that. Novella found this study to be essentially an exercise in examining how we categorise things (how do we define and categorise a disease, for example, or a planet, or a species). How we do so depends on a range of factors, and increasing knowledge, and better technology, helps us to develop parameters for categorising…

Canto: Though this also raises more problems… the more we know or learn, the more problematic our previous categories tend to become…

Jacinta: Anyway, in the case of female and male brains, the researchers distinguished between categorical differences and statistical differences. They used genitalia as a categorical difference. As Novella explains it, with genitalia we have a bimodal system, with male and female equipment…

Canto: I prefer to call it tackle…

Jacinta: And nothing really between. The vast majority of people, as subjects, can be placed in one category or another. Of course there are exceptions, but they are, always arguably, statistically insignificant. So, using this as a yardstick, the researchers wanted to know if there are categorical differences between male and female brains in the same way that there are categorical differences between male and female genitalia. One way to distinguish between categorical and statistical differences is whether, once you know which category an individual belongs to, that provides certainty about their particular traits. If it does, you have a categorical difference. So the researchers looked at about 40 different anatomical and functional aspects of the brain. They found that, generally speaking, there are statistical differences between males and females, in the size of various regions, the richness of the networks in various regions, but with a lot of overlap between the sexes; so it was statistical but not categorical. And the study didn’t look at causes of these differences, whether biological or social (we know that brains can be wired up through social conditioning to some degree). But they also did studies of individuals over the range of the 40 anatomical and functional features to determine how many were ‘typically’ male or female, or somewhere in between. One way to capture this was to ask – what percentage of people had 100% of their brain regions (those 40 features analysed) that were ‘typical’ of their sex? Among the 4 data sets, that percentage was 0 to 8%. So, very few men have ‘all-male’ brain regions, in terms of size and connections. Some 28% to 58% had a mixture of both.

Canto: So let me get this clear, the essential finding, according to Novella, was that though there were statistical differences in specific brain areas – and these are the differences described in ‘Do men and women have different brains?’ in How Stuff Works, from which the new ussr’s earlier post was largely derived – there is a lot of individual variation, which muddies the water rather a lot.

Jacinta: Yes, and I would say hopelessly, at least for those who want to think in stereotypes. As Novella puts it, people are mosaics of male and female traits. Another way of thinking about this, again put succinctly by Novella, is that we can’t assume that because a person is male – or female – we know what that person’s brain regions will be like. Statistical differences can’t automatically tell us about the brain region of any individual. There is no typically male or female brain in the way that there are typically male or female genitalia. And that is really interesting, and it might even mean that it’s illegitimate to say, ‘oh she’s female but she thinks like a man’, or ‘but she has a male brain’. There’s no male brain, or female brain, there are individual brains that are a product of all the influences, genetic, epigenetic, environmental, social, hormonal, psychological, whatever you can think of that influences brain activity and wiring.

Canto: And yet, and yet. Statistical differences do count for something don’t they? We still have the statistics showing that women are more into astrology and naturopathy than men…

Jacinta: Yes but what this study shows is that you can’t base this on some essentialist argument about female brains, and isn’t that a good thing?

Canto: Well, definitely, but then it works the other way. My argument that if women ruled we’d be so much better off can’t be based on anything essentialist either! Maybe being in power would turn their brains into something  like the statistically typical male brain. My hopes are turning to dust…

Jacinto: No, no, don’t despair Canto. Consider the bonobos of the jungle…

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Written by stewart henderson

December 20, 2015 at 11:42 pm

Posted in brain, gender, genetics, ideology, neurology, sex

Tagged with , ,

distributed consciousness – another nail in the coffin of human specialness

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onlinePoster6.jpg

for more on this, the whole conference is available online

I wrote a piece here called ‘Animals R Us’ a few years ago because I was annoyed at certain contemptuous remarks directed at animals – a rather large set to be contemptuous of – and also because I’ve always disliked the idea of human specialness so beloved of some of our religious co-habitants. I was also thinking of the remarks of Marilyn Robinson on consciousness, which I critiqued even more years ago. Atheists, she argued (wrongly) don’t take enough account of consciousness (with the inference that if they did, they’d be more accepting of a supernatural being, presumably). So I’m happy to briefly revisit the complexities and the consciousness of non-humans here.

The latest research reveals more and more the distributed nature of consciousness, and some of this research is summarised in ‘Triumph of the zombie killers’, chapter 1 of Michael Brooks’s book At the edge of uncertainty: 11 discoveries taking science by surprise. He brings up philosopher David Chalmers’s 20-year-old claim about the ‘hard problem’ of consciousness, that it doesn’t appear to be reducible to material processes. In fact, Chalmers went further, saying ‘No explanation given wholly in physical terms can ever account for the emergence of conscious experience.’ Well, forever is a long long time and I wonder what Chalmers would have to say now (I’ll have to check out his more recent pronouncements). In 1994 he used a zombie analogy, suggesting that you couldn’t know whether we were surrounded by zombies, or ‘pretend’ humans, since the sense of self-awareness essential to consciousness cannot be identified or described by methodological naturalism. It’s been difficult to provide a coherent theory to account for this subjective feeling, and Daniel Dennett took the view a couple of decades ago that consciousness is essentially an illusion, or rather an evolved way of dealing with the world which captures the elements of reality we need to get by, and then some. That’s why we can so often be fooled by our brains. We have perceptual glitches and blind spots. An obvious example is the human eye, which only focuses sharply on a tiny area, using the fovea centralis, a patch of densely packed photoreceptor cells only a millimetre in diameter. The rest of our visual field is seen in much lower resolution, and without colour. But we’re not aware of this because of the eye’s movements, or saccades, which average 3 per second. The time between one sharp focus and the next is ‘blacked-out’ of consciousness, creating an illusion of seamlessly moving vision. The analogy with film is obvious.

This evolved use of sight to be ‘good enough’ helps explain our ‘change blindness’, which has been highlighted by a number of recent experiments, and which has been exploited for decades by professional magicians. It also helps explain why we don’t notice mistakes in editorial continuity in films, which are even overlooked by editors, because they involve ‘irrelevant’ background details. This evolved use of eyesight to help us to make enough sense of the world as we need to, as economically as possible, is something shared by many other creatures, as researchers have declared. Consciousness researchers gathered together at Cambridge in July 2012 and issued a ‘declaration on consciousness’, summarising recent findings on consciousness in non-human animals and in infant humans:

Non-human animals have the neuroanatomical, neurochemical, and neurophysiological substrates of conscious states along with the capacity to exhibit intentional behaviours… humans are not unique in possessing the neurological substrates that generate consciousness. Non-human animals, including all mammals and birds, and many other creatures, including octopuses, also possess these neurological substrates

It’s a vitally important point that’s being made here. Even to call consciousness an emergent property is misleading, as it suggests that we’re still hung up on the consciousness label, and on detecting the point at which this phenomenon has ‘emerged’. Previous tests for consciousness are gradually being found wanting, as what they test has little to do with the more expansive understanding of consciousness that our research is contributing to, more and more. What’s more, serious damage to, and indeed the complete loss of, such areas of the human brain as the insular cortex, the anterior cingulate cortex, and the medial prefrontal cortex, all vital to our self-awareness according to previous research, haven’t prevented subjects from articulating clear signs of consciousness and self-reflection. There’s no ‘place’ of consciousness in the human or mammalian brain, and signs of intentionality and individual personality are cropping up in a whole range of species.

Early researchers on chimpanzees and other highly developed animals were often dismissive of claims that they were being cruel, citing ‘anthropomorphism’ as a barrier to scientific progress. We can now see that we don’t have to think of animals as ‘human-like’ to recognise their capacity for suffering and a whole range of other negative and positive experiences and emotions. And we’re only at the beginning of this journey, which, like the journey initiated by Copernicus, Kepler and others, will take us far from the hubristic sense of ourselves as singular and central.

Written by stewart henderson

July 29, 2015 at 10:05 am

what is autism and what causes it?

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Brain_Autism

The term ‘autism’ was coined in the 1940s by two physicians working independently of each other, Hans Asperger in Austria and Leo Kanner in the USA, to describe a syndrome the key feature of which was a problem with interacting with others in ‘normal’ ways. Sounds vague, but the problem was anything but wishy-washy to these individuals’ parents and families, and over time a more detailed profile has built up.

The term itself is from the Greek autos, or ‘self’, because those with the syndrome had clear difficulties in interpreting others’ moods and responses, resulting in a withdrawn, often antisocial state. Autistic kids often avoid eye contact and are all at sea over the simplest communication.

Already though, I feel I’m saying too much. When describing autism, it’s common to use words like ‘often’ or ‘sometimes’ or ‘some’, because the symptoms are seemingly so disparate. Much of what follows relies on the neurologist V S Ramachandran’s book The tell-tale brain, especially chapter 5, ‘Where is Steven? The riddle of autism’.

Autistic symptoms can be categorised in two major groups, social-cognitive and sensorimotor. The social-cognitive symptoms include mental aloneness and a lack of contact with the world of other humans, an inability to engage in conversation and a lack of emotional empathy. Also a lack of any overt ‘playfulness’ or sense of make-believe in childhood. These symptoms can be ‘countered’ by heightened, sometimes obsessive interest in the inanimate world – e.g. the memorising of ostensibly useless data, such as lists of phone numbers.

On the sensorimotor side, symptoms include over-sensitivity and intolerance to noise, a fear of change or novelty, and an intense devotion to routine. There’s also a physical repetitiveness of actions and performances, and regular rocking motions.

These two types of symptoms raise an obvious question – how are the two types connected to each other? We’ll return to that.

Another motor symptom, which Ramachandran thinks is key, is a difficulty in physically imitating the actions of others. This has led him to pursue the hypothesis that autism is essentially the result of a deficiency in the mirror neuron system.

In recent years there’s been a lot of excitement about mirror neurons – possibly too much, according to some neurologists. A mirror neuron is one that fires not only when we perform an action but also when we observe it being performed by others. They’ve been found to act in mammals and also, it seems, in birds, and in humans they’ve been found in the premotor cortex, the supplementary motor area, the primary somatosensory cortex and the inferior parietal cortex. It’s easier, however, to locate them than it is to determine their function. Clearly, to describe them as ‘responsible’ for empathy, or intention, is to go too far. As Patricia Churchland points out, ‘a neuron is just a neuron’, and what we describe as empathy or intention will likely involve a plethora of high-order processes and connections, in which mirror neurons will play their part.

With that caveat in mind, let’s continue with Ramachandran’s speculations on autism and mirror neurons. First, we’ll need to be reminded of the term ‘theory of mind’, used regularly in psychology. It’s basically the idea that we attribute to others the same sorts of intentions and desires that we have because of the assumption that they, like us, have that internal feeling and processing and regulating system we call a ‘mind’. A sophisticated theory of mind is one of the most distinctive features of the human species, one which gives us a unique kind of social intelligence. That autism would be related to theory-of-mind deficiencies seems a reasonable assumption, so what is the brain circuitry behind theory of mind, and how do mirror neurons fit into this picture?

Although neuro-imaging has revealed that autistic children have larger brains with larger ventricles (brain cavities) and notably different activity within the cerebellum, this hasn’t helped researchers much, because autism sufferers don’t present any of the usual symptoms of cerebellum damage. It could be that these changes are simply the side effects of genes which produce autism. Some researchers felt it was better to focus on mirror neurons straight-off, as obvious suspects, and to see how they fired and where they connected in particular situations. They used EEG (electroencephalography) as a non-invasive way to observe mirror neuron activity. They focused on the suppression of mu waves, a type of brain wave. It has long been known that mu waves are suppressed when a person makes any volitional movement, and more recently it has been discovered that the same suppression occurs when we watch others performing such movements.

So researchers used EEG (involving electrodes placed on the scalp) to monitor neuronal activity in a medium-functioning autistic child, Justin. Justin exhibited a suppressed mu wave, as expected, when asked to make voluntary movements. However, he didn’t show the same suppression when watching others perform those movements, as ‘neurotypical’ children do. It seemed that his motor-command system was functioning more or less normally, but his mirror-neuron system was deficient. This finding has been replicated many times, using a variety of techniques, including MEG (magnetoencephalography). fMRI, and TMS (transcranial magnetic stimulation). Reading about all these techniques would be a mind-altering experience in itself.

According to Ramachandran, all these confirmations ‘provide conclusive evidence that the [mirror neuron] hypothesis is correct.’ It certainly helps to explain why a subset of autistic children have trouble with metaphors and literality. They have difficulty separating the physical and the referential, a separation that mirror neurons appear to mediate somehow.

A well-developed theory of mind which can anticipate the behaviour of others is clearly a feature of understanding our own minds better. In Ramachandran’s words:

If the mirror-neuron system underlies theory of mind and if theory of mind in normal humans is supercharged by being applied inward, towards the self, this would explain why autistic individuals find social interaction and strong self-identification so difficult, and why so many autistic children have a hard time correctly using the pronouns ‘I’ and ‘you’ in conversation. They may lack a mature-enough self-representation to understand the distinction.

Of course, tons more can be said about the ‘mirror network’ and tons more research remains to be done, but there are many promising signs. For example, the findings about lack of mu wave suppression could be used as a diagnostic tool for the early detection of autism, and some interesting work is being done on the use of biofeedback to treat the disorder. Biofeedback is a process whereby physiological signals picked up by a machine from the brain or body of a subject are represented to the subject in such a way that he or she might be able to affect or manipulate that signal by a conscious change of behaviour or thinking. Experiments have been done to show that subjects can alter their own brain waves through this process. Some experimental work is also being done with drugs such as MDMA (otherwise known as the party drug ‘ecstacy’) which appear to enhance empathy through their action on neurotransmitter release.

So that’s a very brief introduction to autism. Hopefully I’ll come back to it in the future to explore the progress being made in understanding and treating the syndrome.

Written by stewart henderson

October 23, 2013 at 10:25 am

What do we currently know about the differences between male and female brains in humans?

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Having had an interesting conversation-cum-dispute recently over the question of male-female differences, and having then listened to a podcast, from Stuff You Should Know, on the neurological differences between the human male and the human female, which contained some claims which astonished me (and for that matter they astonished the show’s presenters), I’ve decided to try and satisfy my own curiosity about this pretty central question. Should be fun.

The above link is to How Stuff Works, which I think is the written version of the Stuff You Should Know podcast, that’s to say with more content and less humour (and less ads), but I do recommend the podcast, because the guys have lots of fun with it while still delivering plenty of useful and thought-provoking info. Anyway, the conversation I was talking about was one of those kitchen table, wine-soaked bullshit sessions in which one of the participants, a woman, was adamant that nurture was pretty well entirely the basis for male-female differences. I naturally felt sympathetic to this view, having spent much of my life trying to blur the distinctions between masculinity and femininity, having generally been turned off by ultra-masculine and ultra-feminine traits and wanting to push for blended behaviour, which obviously suggests we can control these things through nurturing such a blending. However, I had just enough knowledge of what research has revealed about the matter to say, ‘well no, there are distinct neurological differences between males and females’, but I didn’t have enough knowledge to give more than a vague idea of what these differences were. The podcast further whetted my appetite, but writing about it here should pin things down in my mind a bit more, here’s hoping.

I’ve chosen the title of this post reasonably carefully, with apologies for its clunkiness. For the fact is, we still know little enough about our brains. I’ve mentioned humans, but I expect there are gender differences in the brains of all mammals, so I’m particularly interested in that part of the brain that distinguishes us, though not completely, from other mammals, namely the prefrontal cortex.

Here’s an interesting summary, from a blurb on a New Scientist article by Hannah Hoag from 2008;

Research is revealing that male and female brains are built from markedly different genetic blueprints, which create numerous anatomical differences. There are also differences in the circuitry that wires them up and the chemicals that transmit messages between neurons. All this is pointing towards the conclusion that there is not just one kind of human brain, but two. …

Men have bigger brains on average than women, even accounting for sexual dimorphism, but the two sexes are bigger in different areas. A 2001 Harvard study found that some frontal lobe regions involved in problem-solving and decision-making were larger in women, as well as regions of the limbic cortex, responsible for regulating emotions. On the other hand, areas of the parietal cortex and the amygdala were larger in men. These areas regulate social and sexual behaviour.

The really incredible piece of data, though, is that men have about 6.5 times more grey matter (neurons) than women, while women have about ten times more white matter (axons and dendrites, that’s to say connections) than men. These are white because they’re sheathed in myelin, which allows current to flow much faster. On the face of it, I find this really hard, if not impossible, to believe. I mean, that’s one effing huge difference. It comes from a study led by Richard Haier of the University of California, Irvine and colleagues from the University of New Mexico, but this extraordinary fact appears to be of little consequence for male performance in intellectual tasks as compared to female. What appears to have happened is that two different ‘brain types ‘ have evolved alongside and in conjunction with each other to perform much the same tasks. Other research appears to confirm this amazing fact, finding that males and females access different parts of the brain for performing the same tasks. In an experiment where men and women were asked to sound out different words, Gina Kolata reported on this back in early 1995 in the New York Times:

The investigators, who were seeking the basis of reading disorders, asked what areas of the brain were used by normal readers in the first step in the process of sounding out words. To their astonishment, they discovered that men use a minute area in the left side of the brain while women use areas in both sides of the brain.

After lesions to the left hemisphere, men more often develop aphasia (problems with understanding and formulating speech) than women.

While I’m a bit sceptical about the extent of the differences between grey and white matter in terms of gender, it’s clear that these and many other differences exist, but they’re difficult to summarise. We can refer to different regions, such as the amygdala, but there are also differences in hormone activity throughout the brain, and so many other factors, such as ‘the number of dopaminergic cells in the mesencephalon’, to quote one abstract (it apparently means the number of cells containing the neurotransmitter dopamine in the midbrain). But let me dwell a bit on the amygdala, which appears to be central to neurophysiological sex differences.

Actually, there are 2 amygdalae, located within the left and right temporal lobes. They play a vital role in the formation of emotional memories, and their storage in the adjacent hippocampus, and in fear conditioning. They’re seen as part of the limbic system, but their connections with and influences on other regions of the brain are too complex for me to dare to elaborate here.  The amygdalae are larger in human males, and this sex difference appears also in children from age 7. But get this:

In addition to size, other differences between men and women exist with regards to the amygdala. Subjects’ amygdala activation was observed when watching a horror film. The results of the study showed a different lateralization of the amygdala in men and women. Enhanced memory for the film was related to enhanced activity of the left, but not the right, amygdala in women, whereas it was related to enhanced activity of the right, but not the left, amygdala in men.

This right-left difference is significant because the right amygdala connects differently with other brain regions than the left. For example, the left amygdala has more connections with the hypothalamus, which directs stress and other emotional responses, whereas the right amygdala connects more with motor and visual neural regions, which interact more with the external world. Researchers are of course reluctant to speculate beyond the evidence, but as a non-scientist, but as a pure dilettante I don’t give a flock about that – just don’t pay attention to my ravings. It seems to me that most female mammals, who have to tend offspring, would be more connected to the flight than the fight response to danger than the unencumbered males would be??? OMG, is that evolutionary psychology?

It’s interesting but hardly surprising to note that studies have shown this right-left amygdala difference is also correlated to sexual orientation. Presumably – speculating again – it would also relate to those individuals who sense from early on that they’re born into ‘the wrong gender’.

Neuroimaging studies have found that the amygdala develops structurally at different rates in males and females, and this seems to be due to the concentration of sex hormone receptors in the different genders. Where there’s a size difference there appears to be a big difference in number of sex hormones circulating in the area. Again this is difficult to interpret, and it’s early days for this research. One brain structure, the stria terminalis, a bundle of fibres that constitute the major output pathway for the amygdala, has become a focus of controversy in the determination of our sense of gender and sexual orientation. As a dilettante I’m reluctant to comment much on this, but the central subdivision of the bed nucleus of the stria terminalis is on average twice as large in men as in women, and contains twice the number of somatostatin neurons in males. Somatostatin is a peptide hormone which helps regulate the endocrine system, which maintains homeostasis.

What all this means for the detail of sex differences is obviously very far from being worked out, but it seems that the more we examine the brain, the more we find structural and process differences between the male and female brain in humans. And it’s likely that we’ll find similar differences in other mammals.

It’s important to note, though, that these differences, as in other mammals, exist in the same species, in which the genders have evolved to be codependent and to work in tandem towards their survival and success. Just as it would seem silly to say that female kangaroos are smarter/dumber than males, the same should be said of humans. The terms smart/dumb are not very useful here. The two genders, in all mammals, perform complementary roles, but they’re also also both able to survive independently of one another. The amazing thing is that such different brain designs can be so similar in output and achievement. It’s more impressive evidence of the enormous diversity of evolutionary development.

Written by stewart henderson

October 6, 2013 at 9:30 am