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how statins work 3: the beginnings of cholesterol, from Acetyl-CoA

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Coenzyme A – an acetyl group attaches to the -SH shown in red

So how is cholesterol made in the body? We need to know this in order to understand how statins inhibit or interfere with this process.

I’ve shown the actual structure of cholesterol in part 1 of this series, but remember it’s a sterol, which is a steroid – four carbon rings with hydrogen atoms attached – in which one of the hydrogens is replaced by an alcohol group. The particular form of sterol called cholesterol, with a 7-carbon chain attached to the end-carbon ring (the D ring), and three methyl groups attached to specific carbons in the rings and chain (it’s better to look at the skeletal structure in part 1). There are precisely 27 carbon atoms specifically placed within the molecule.

I’m using a set of videos to understand how cholesterol is synthesised – it might be best to look at them yourself, but I’m writing it all down to improve my own understanding. So we start by understanding something about acids and their conjugate bases. Apparently an acid is a molecule which is capable of donating protons into solution. Take pyruvic acid and its conjugate base pyruvate. Here’s what Wikipedia says about them:

Pyruvic acid (CH3COCOOH) is the simplest of the alpha-keto acids, with a carboxylic acid and a ketone functional group. Pyruvate, the conjugate base, CH3COCOO, is a key intermediate in several metabolic pathways throughout the cell.

I don’t understand the first sentence, but no matter, pyruvic acid is a 3-carbon molecule with a carboxylic acid at one end and a ketone group in the middle of the molecule (according to Britannica, a ketone is ‘any of a class of organic compounds characterized by the presence of a carbonyl group in which the carbon atom is covalently bonded to an oxygen atom. The remaining two bonds are to other carbon atoms or hydrocarbon radicals)’. The proton that comes off the oxygen of the alcohol group of the pyruvic acid can be donated into the surrounding solution, increasing its acidity. The pyruvic acid is thus transformed into its negatively charged conjugate base (it’s no longer capable of donating protons but it can receive them). This is the case with all acids in the cytoplasm of cells. As inferred in the quote above, conjugate bases are vital components of biosynthetic pathways. Most of the molecules in the cytoplasm will exist as pyruvate at a physiological pH of around 7.5.

Next – and hopefully this will become clear eventually – we’re going to look at two molecules, NAD+ (nicotinamide adenine dinucleotide) and NADP+ (nicotinamide adenine dinucleotide phosphate). They transport electrons, and are capable of accepting a hydride anion, which is a hydrogen atom with a negative charge. The normal hydrogen atom, called protium, has a proton and an electron only. When it donates away its electron it becomes a hydrogen cation, and when it gains an electron it becomes a hydride anion.

NAD+ is an adenine organic base bound to a ribose sugar. Then there are two phosphate groups coming off the ribose sugar, the second of which attaches to another ribose sugar. This second ribose sugar has nicotinamide attached to it (see below),

in which the phosphate groups are magenta-coloured circles. To explain something about ribose sugars, here’s something from Pearson Education:

The 5-carbon sugars ribose and deoxyribose are important components of nucleotides, and are found in RNA and DNA, respectively. The sugars found in nucleic acids are pentose sugars; a pentose sugar has five carbon atoms. A combination of a base and a sugar is called a nucleoside. Ribose, found in RNA, is a “normal” sugar, with one oxygen atom attached to each carbon atom. Deoxyribose, found in DNA, is a modified sugar, lacking one oxygen atom (hence the name “deoxy”). This difference of one oxygen atom is important for the enzymes that recognize DNA and RNA, because it allows these two molecules to be easily distinguished inside organisms.

So, just for my own understanding, nucleotides include phosphate groups. NAD+ is a dinucleotide, with two nucleotides (ribose sugars with phosphate groups attached), attached to adenine and to nicotinamide molecules. Also, NAD+ has a positive charge around the nicotinamide – on its nitrogen atom.

NAD+ becomes neutralised by accepting a hydride anion (one proton and two electrons) and becomes NADH, or reduced NAD. Now, remembering NADP+, it has an extra phosphate group on the ribose sugar of the adenine nucleotide (also called an organic base, apparently). Like NAD+, NADP+ can accept a hydride anion (becoming reduced NADP) and then later exchange it in another reaction. Effectively these molecules are electron carriers, collecting electrons and transporting them to where they’re needed for other reactions.

Now to introduce something else completely new for me – Acetyl-CoA (acetyl coenzyme A). A quick grab again, this time from Wikipedia:

Acetyl-CoA is a molecule that participates in many biochemical reactions in protein, carbohydrate and lipid metabolism. Its main function is to deliver the acetyl group to the citric acid [Krebs] cycle to be oxidized for energy production

Acetyl-CoA is found, and presumably produced, in mitochondria, and as part of this cholesterol-synthesising pathway it needs to be removed from the ‘mitochondrial matrix’. What’s that, I ask. So here’s a bit about the mitochondrial matrix, from yet another source, this time

The mitochondrion consists of an outer membrane, an inner membrane, and a gel-like material called the matrix. This matrix is more viscous than the cell’s cytoplasm as it contains less water. The mitochondrial matrix has several functions.It is where the citric acid cycle takes place. This is an important step in cellular respiration, which produces energy molecules called ATP. It contains the mitochondrial DNA in a structure called a nucleoid. A mitochondrion contains its own DNA and reproduces on its own schedule, apart from the host cell’s cell cycle. It contains ribosomes that produce proteins used by the mitochondrion. It contains granules of ions that appear to be involved in the ionic balance of the mitochondrion.

So basically this matrix is like (or equivalent to) the cell’s cytoplasm, only more viscous, and contains ribosomes, one or more nucleoids and ionic granules, inter alia.

Acetyl-CoA is essential to the biosynthesis of cholesterol, and is found initially in the mitochondrial matrix, and we need to look at the pathway for its removal from that matrix into the cytoplasm, where all the action occurs.

Intruding into the mitochondrial matrix from the (quite impermeable) inner cell membrane are the cristae, which give the membrane more of a surface layer for interactions. This inner membrane is the site of oxidative phosphorylation. What’s that, I ask. Well, it’s key to the production of ATP, and at least I know that ATP is the ‘energy molecule’, and that it’s produced in mitochondria. Here’s something about the process from Khan Academy:

Oxidative phosphorylation is made up of two closely connected components: the electron transport chain and chemiosmosis. In the electron transport chain, electrons are passed from one molecule to another, and energy released in these electron transfers is used to form an electrochemical gradient. In chemiosmosis, the energy stored in the gradient is used to make ATP.

So a strong proton gradient is built up across the inner membrane of the mitochondrion. It’s a concentration gradient but also an ‘electrical potential difference’ gradient, so that the electrical potential within the matrix is lower, by some 160 millivolts, than that across the inter-membrane space. The protons within this space are unable to pass back into the matrix. The only way they can get back into the matrix is by means of ATP synthase which can harness the energy from the protons as they move down the chemical and electrical gradient, and use that energy to bind ADP to inorganic phosphate to create ATP.

I don’t fully understand all that, but the main point here is that the mitochondrial inner membrane is very ‘tight’, which makes it difficult to transfer Acetyl-CoA out of the matrix and into the inter-membrane space, from which it can more easily diffuse through the more permeable outer membrane into the cytoplasm.

The structure of Acetyl-CoA: it consists of an acetic acid molecule (CH3COOH) with a thioester link to the thiol group of a coenzyme A molecule. The importance for us here is this thiol (HS) group, which is similar structurally to an alcohol (HO) group, as sulphur has similar properties to its periodic table neighbour, oxygen. So thiol groups can be linked to carboxylic acid groups as alcohol groups can. Acetyl essentially means acetic acid with the alcohol removed. To get this Acetyl-CoA out of the matrix, it is first bound to oxaloacetate, a four-carbon molecule, to create citrate, the first molecule of the citric acid cycle. This citrate can be passed through the mitochondrial inner membrane and into the cytoplasm where it can be converted back into Acetyl-CoA.

So the conjugate base, oxaloacetate, has carboxylic acid groups, attached to the first and fourth carbon atoms, that have lost their protons into solution. An enzyme within the matrix is able to combine oxaloacetate with Acetyl-CoA and water to create citrate…

Okay, this is proving to be a much longer story than I might’ve hoped, but I like to be thorough – and in reality I’m still not being thorough enough. There’s a lot of rubbish on the internet about statins, much of it self-serving in one way or another, so I’ll just keep plodding along until I feel at least halfway informed about the matter. Meanwhile, you just keep getting on with your work, and don’t mind me.


Cholesterol biosynthesis part 1, by Ben1994, 2015

Cholesterol biosynthesis part 2, by Ben 1994, 2015

Written by stewart henderson

October 14, 2019 at 5:26 pm

women of note 1: Mary Anning, palaeontologist

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She sells sea-shells on the sea-shore,
The shells she sells are sea-shells, I’m sure
For if she sells sea-shells on the sea-shore
Then I’m sure she sells sea-shore shells. 

Terry Sullivan, 1908 – said to be inspired by Mary Anning’s fossickings

Unfortunately, I want to write about everything.

So now I begin an occasional series about women to be celebrated and never forgotten.

Mary Anning was born in the seaside town of Lyme Regis, Devon, in 1799 and died there, too young, of breast cancer in 1847. According to Brian Ford, author of Too big to walk: the new science of dinosaurs, she was ‘the first full-time professional palaeontologist anywhere in the world’. It’s a fair statement; those before her were generalists, given the name ‘naturalists’, and made their livings as pastors or physicians, or were independently wealthy. The term ‘palaeontology’ was just starting to gain traction in the early nineteenth century, replacing the intriguing but probably short-lived ‘oryctology’, though fossil-finding and speculations thereon (mostly infused with religious or mystic beliefs) date back to civilisation’s dawn.

Fossil-hunting had become quite trendy from the late eighteenth century, and Mary’s dad, a cabinet-maker by trade, supplemented his income by selling fossil bits and pieces, discovered himself on the nearby cliffs, to locals and tourists (the region had become something of a haven for those escaping the Napoleonic wars). The cliffs around Lyme Regis on England’s south coast form part of the Blue Lias, alternating sediments of shale and limestone, very rich in fossils from the early Jurassic, around 200 mya.

Richard and Molly, Mary’s parents, had ten children, but only two, Joseph and Mary, survived infancy. Childhood diseases such as measles were often killers, especially among the poor – a reminder of how lucky we are to be living in an economically developed country in the 21st century. The Anning family was never well-off, and Richard died when Mary was just 11 years old. Mary herself just managed to escape death by lightning strike when she was a baby. The strike killed three women, one of whom was tending her at the time. But the family suffered many hardships besides infant mortality. Food shortages and rising prices led to riots in the neighbourhood, and Richard himself was involved in organising protests.

As kids, Joseph and Mary sometimes accompanied their father on fossil-hunting trips on the dangerous cliffs, which were subject to landslides. They would sell their finds, which were mostly of invertebrate fossils such as ammonite and belemnite shells, in front of their home, but clearly life would’ve been a real struggle in the years following Richard’s death, during which time they relied partly on charity. It wasn’t long, though, before Mary’s expertise in finding and identifying fossils and her anatomical know-how came to the attention of well-heeled fossickers in the region. In the early 1820s a professional collector, Thomas Birch, who’d come to know the family and to admire Mary’s skills in particular, decided to auction off his own collection to help support them. This further enhanced their reputation, and Mary became something of a local celebrity, reported on in the local papers:

This persevering female has for years gone daily in search of fossil remains of importance at every tide, for many miles under the hanging cliffs at Lyme, whose fallen masses are her immediate object, as they alone contain these valuable relics of a former world, which must be snatched at the moment of their fall, at the continual risk of being crushed by the half-suspended fragments they leave behind, or be left to be destroyed by the returning tide: – to her exertions we owe nearly all the fine specimens of ichthyosauri of the great collections.

Bristol Mirror, 1823 – quoted in Too big to walk, by Brian Ford, p61

As this article mentions, Mary Anning’s name is often associated with ichthyosaur fossils, but she also discovered the first plesiosaur, the identity of which was confirmed by Georges Cuvier – though he at first accused her of fraud. Amongst other contributions, she was the first to recognise that the conical ‘bezoar stones’ found around the cliffs of Lyme were in fact fossilised faeces of ichthyosaurs and plesiosaurs.

plesiosaur skeleton, beautifully sketched by Mary Anning

For my information, ichthyosaurs were marine reptiles dated from the early Triassic to the late Cretaceous periods (250-90 mya), though most abundant in the early period, after which they were superseded as the top marine predators by the plesiosaurs (approx 204-66 mya).

Anning’s exact contribution to palaeontology is impossible to determine, because so many of her finds were snapped up by professional collectors, in an era when attributions weren’t preserved with much care, and this would have been compounded by her status as an ‘uneducated’ amateur, and a woman. Contemporary commentary about her expertise was often infused with a subtle condescension. There’s little doubt that, had she been male, her admirers would have seen to it that her talents were sufficiently recompensed with scholarships, senior university posts, and membership of the prominent scientific societies. Instead, she remained a fixture at Lyme Regis – there’s no indication that she ever travelled, apart from at least one trip to London, though her expertise was recognised throughout Europe and America. It’s also likely that, coming from a family of Dissenters – a reformist Protestant group – she was regarded with suspicion by the Anglican-dominated scientific hierarchy of the time. Let’s take a look, for comparison, at some of the males she associated with, and who associated with her, and how their professional lives went:

Sir Henry de La Beche – KCB, FRS. That first TLA means ‘Knight Commander of the Bath’ or something similar. I seem to recall bestowing a similar title upon myself while commanding battleships in the bathtub at age six or so. Never received a stipend for it though. FRS means Fellow of the Royal Society of course. Son of a slave-owner who died young, Beche was brought up in Lyme Regis where he became a friend of Anning, sharing her interest in geological strata and what they contained. It’s not unlikely that she was an inspiration for him. He was able to join the male-only London Geological Society at age 21, and later became its President. He became a FRS in 1819 at the still tender age of 24. He was appointed director of the Geological Survey of Great Britain in the 1830s and later the first director of the Museum of Practical Geology in London (now part of the Natural History Museum). He was knighted for his genuine contributions to geology in 1848. Beche was in fact an excellent practical and skeptical scientist who gave support to Anning both financially and in his published work.

William Conybeare – FRS. Born into a family of ‘divines’ (at least on the male side) Conybeare became a vicar himself, and a typical clergyman-naturalist, with particular interests in palaeontology and geology. Educated at the elite (and all-male) Westminster School and at all-male Oxford University, after which he travelled widely through the country and on the Continent (all paid for by ‘a generous inheritance’) in pursuit of geological and palaeontological nourishment. He became an early member of the Geological Society, where he met and advised other notables such as Adam Sedgwick and William Buckland, and contributed papers, including one with Beche which summarised findings about ichthyosaurs and the possibility of another species among them, the plesiosaur. This was confirmed by Anning’s discovery and detailed description of a plesiosaur, which Conybeare later reported to the Geological Society, delighted to be proved correct. He failed to mention Anning’s name. In 1839 Conybeare, together with two other naturalist heavyweights, William Buckland and Richard Owen, joined Mary Anning for a fossil-hunting excursion. Unfortunately we have no smartphone recordings of that intriguing event.

William Buckland, DD [Doctor of Divinity], FRS. Born and raised in Devon, Buckland accompanied his clergyman dad on walks in the region where he collected fossil ammonite shells. He was educated at another elite institution, Winchester College, where he won a scholarship to Oxford. In 1813 he was appointed reader in minerology there, and gave popular lectures with emphasis on geology and palaeontology. He seemed to cultivate eccentricities, including doing field-work in his academic gown and attempting to eat his way though the animal kingdom. His most important association with Mary Anning was his coining of the term ‘coprolite’ based on Anning’s observation that these conical deposits, found in the abdomens of ichthyosaurs, were full of small skeletons. Clearly, Anning knew exactly what they were, but had no real opportunity to expatiate on them in a public forum. Women were often barred from attending meetings of these proliferating scientific societies even as guests, let alone presenting papers at them.

Gideon Mantell, MRCS [Member of the Royal College of Surgeons], FRS. Mantell was himself a rather tragic figure, whose association with Anning was less personal, though he did visit her once at her Lyme Regis shop. He was inspired more by news of her ichthyosaur discoveries, which reinforced an obsession with fossil hunting in his own region of Sussex, where many fossils of the lower Cretaceous were uncovered. Born in Lewes in Sussex, the fifth child of a shoemaker, he was barred from the local schools due to his family’s Methodism. He underwent a period of rather eccentric but obviously effective private tuition before becoming apprenticed to a local surgeon. Though worked very hard, he taught himself anatomy in his free time, and wrote a book on anatomy and the circulation of the blood. He travelled to London for more formal education and obtained a diploma from the Royal College of Surgeons in 1811. Returning to Lewes, he partnered with his former employer in treating victims of cholera, smallpox and typhoid epidemics, and delivering large quantities of babies, building up a thriving practice, but also somehow finding time for fossil-hunting, corresponding with others on fossils and geology, and writing his first paper on the fossils of the region. He started finding large and unusual bones and teeth, which turned out to be those of an Iguanadon, though it took a long time for this to be recognised, and he was mocked for his claims by experts such as William Buckland and Richard Owen. Although he was becoming recognised for his many writings and discoveries, he always remained something of an outsider to the establishment. He later fell on hard times and suffered a serious spinal injury from a horse-and-carriage accident, from which he never really recovered. He apparently died from an overdose of laudanum, used regularly as a pain-killer in those days.

Returning to Mary Anning, we see that class as well as sex was a barrier to intellectual acceptance in early nineteenth century Britain – but sex especially. Mary struggled on in Lyme Regis, recognised and sought out by other experts, but never given her full due. In the 1840s she was occasionally seen to be staggering about, as if drunk. In fact, she too was dosing herself on laudanum, due to the pain of advancing breast cancer. She died in 1847, aged 47.

I should point out that, though Mary Anning’s name is largely unknown to the general public, so are the male names mentioned in this article. We generally don’t fête our scientists very much, though they’re the ones that really change our world, and help us to understand it. Mary was helped out by luminaries such as Beche and Buckland in her later years, and received a small annuity from the British Association for the Advancement of Science. Upon her death, Beche wrote a modest eulogy, which he presented at a Geological Society meeting, which, had she been alive, Anning wouldn’t have been allowed to attend. It was later published in the transactions of the Society. Here’s how it begins:

 I cannot close this notice of our losses by death without adverting to that of one, who though not placed among even the easier classes of society, but one who had to earn her daily bread by her labour, yet contributed by her talents and untiring researches in no small degree to our knowledge of the great Enalio-Saurians [now known as Euryapsida], and other forms of organic life entombed in the vicinity of Lyme Regis ..

Mary Anning by her beloved cliffs, tool in hand, pointing to her not yet dead dog Tray, killed in the line of scientific duty…


Written by stewart henderson

September 24, 2019 at 11:14 am

why do our pupils dilate when we’re thinking hard?

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Canto: So we’re reading Daniel Kahneman’s Thinking fast and slow, among other things, at the moment, and every page has stuff worth writing about and exploring further, it’s impossible to keep up.

Jacinta: Yes with this stuff it’s a case of reading slow and slower. Or writing about it faster and faster, unlikely in our case. A lot of it might be common knowledge, but not to us, though in these first fifty pages or so he’s getting into embodied cognition, which we’ve written about, but there’s new data here that I didn’t know about but which makes a lot of sense to me.

Canto: That’s because you’ve been primed to accept this stuff haha. But I want to focus here more narrowly on experiments Kahneman did early in his career with Jackson Beatty, who went on to become the leading figure in the study of ‘cognitive pupillometry’.

Jacinta: Presumably measuring pupils, which is easy enough, while measuring cognition or cognitive processes, no doubt a deal harder.

Canto: Kahneman tells the story of an article he read in Scientific American – a mag I regularly read in the eighties, so I felt all nostalgic reading this.

Jacinta: Why’d you stop reading it?

Canto: I don’t know – I had a hiatus, then I started reading New Scientist and Cosmos. I should get back to Scientific American. All three. Anyway, the article was by Eckhard Hess, whose wife noticed that his pupils dilated when he looked at lovely nature pictures. He started looking into the matter, and found that people are judged to be more attractive when their pupils are wider and that belladonna, which is used in cosmetics, also dilates the pupils. More importantly for Kahneman, he noted ‘the pupils are sensitive indicators of mental effort’. Kahneman was looking for a research project at the time, so he recruited Beatty to help him with some experiments.

Jacinta: And the result was that our pupils dilate very reliably, and quite significantly, when we’re faced with tough problem-solving tasks, like multiplying double-digit numbers – and they constrict again on completion, so reliably that the monitoring researcher can surprise the subject by saying ‘so you’ve got the answer now?’

Canto: Yes, the subjects were arranged so the researchers could view their eyes magnified on a screen. And of course this kind of research is easy enough to replicate, and has been. My question, though, is why does the pupil dilate in response to such an internal process as concentration? We think of pupils widening to let more light in at times of dim light, that makes intuitive sense, but – in order to seek a kind of metaphorical enlightenment? That’s fascinating.

Jacinta: Well I think you’re hitting on something there. Think of attention rather than concentration. I suspect that our pupils widen when we attend to something important or interesting. As Eckhard Hess’s wife noticed when he was looking at a beautiful scene. In the case of a mathematical or logical problem we’re attending to something intently as well, and the fact that it’s internal rather than external is not so essential. We’re looking at the problem, seeing the problem as we try to solve it.

Canto: Yes but again that’s a kind of metaphorical seeing, whereas your pupils don’t dilate metaphorically.

Jacinta: Yes but it’s likely that our pupils dilate in the dark only when we’re trying to see in the dark. Making that effort. When we turn off the light at night in our bedroom before going to sleep, it’s likely that our pupils don’t dilate, because we’re not trying to see the familiar objects around us, we just want to fall asleep. So even if we leave our eyes open for a brief period, they’re not actually trying to look at anything. It’s like when you enter a classroom and see a maths problem on the board. Your eyes won’t dilate just on noticing the problem, but only when you try to solve it.

Canto: I presume there’s been research on this – like with everything we ever think of. What I’ve found is that the ‘pupillary light reflex’ is described as part of the autonomous nervous system – an involuntary system, largely, which responds ‘autonomously’, unconsciously, to the amount of light it receives. But as you say, there are probably other over-riding features, coming from the brain rather than outside. However, a pupil ‘at rest’, in a darkened room, is usually much dilated. So dilation is by no means always to do with attention or focus.

Jacinta: Well there’s a distinction made in neurology between bottom-up and top-down processing, which you’ve just alluded to, in the sense that information coming from outside, and sensed on the skin, the eye and other sensory organs, is sent ‘up’ to the brain – the Higher Authority, – which then sends down responses, in this case to dilate or contract the pupil, all that is called bottom-up processing. But researchers have found that the pupil isn’t just regulated in a bottom-up way.

Canto: And that’s where cognitive pupillometry comes in.

Jacinta: And here are some interesting research findings regarding top-down influences on pupil size. When subjects were primed with pictures relating to the sun, even if they were’nt bright, their pupils contracted more than with pictures of the moon, even if those pictures were actually brighter than the sun pictures. And even words connected to brightness made their pupils contract. There’s also been solid research to back up the speculations of Eckhard Hess, that emotional scenes, images and memories, whether positive or negative, have a dilating effect on our pupils. For example, hearing the cute sound of a baby laughing, and the disturbing sound of a baby screaming, widens our pupils, while more neutral sounds of road traffic or workplace hubub have very little effect.

Canto: Because there’s nothing, or maybe too much info, to focus our attention, surely? While the foregrounded baby’s noises stimulate our sense of wonder, of ‘what’s happening?’ We’re moved to attend to it. Actually this reminds me of something apparently unrelated but maybe not. That’s the well-known problem that we’re moved to give to a charity when one suffering child is presented in an advertisement, and less and less as we’re faced with a greater and greater number of starving children. These numbers become like distant traffic, they disperse our attention and interest.

Jacinta: Yes well that’s a whole other story, but this brings us to the most interesting of findings re top-down effects on our pupils, and the question we’ve asked in the title. A more scientific name for thinking hard is increased cognitive load, and countless experiments have shown that increasing cognitive load, for example by solving tough maths problems, or committing stacks of info to memory, correlates with increased pupillary dilation. This hard thinking is done in the prefrontal cortex, but we won’t go into detail here about its more or less contested compartments. What I will say is there’s an obvious difference between thinking and memorising, and both of these activities increase cognitive load, and pupillary dilation. Some very interesting studies relating memorising and pupillary dilation have shown that children under a certain age, unsurprisingly, are less able to hold info in short-term memory than adults. The research task was to memorise a long sequence of numbers. Monitoring of pupil response showed that the children’s pupils would constrict from their dilated state after six numbers, unlike those of adults.

Canto: So, while we may not have a definitive answer to our title question – the why question – it seems to be that cognitive load, like any load that we carry, requires the expenditure of energy, which can be manifested in the tightening of muscles in the eye which dilates the pupils. This dilation reveals, apparently, that we’re attending to something or concentrating on something. I can see some real-world applications. Imagine, as a teacher, having a physics class, say. You could get your students to wear special glasses that monitor the dilation and constriction of their pupils – I’m sure such devices could be rigged up, and connected to a special console at the teacher’s desk, so he could see who in the class was paying close attention and who was off in dreamland…

Jacinta: Yeah right haha – even if that was physically possible, there are just a few privacy issues there, and how would you know if the pupillary dilation was due to the fascinating complexities of electromagnetism or the delightful profile of your student’s object of fantasy a couple of seats away? Or how could you know if their apparent concentration had anything much to do with comprehension? Or how would you know if their apparent lack of concentration was to do with disinterest or incomprehension or the fact they were way ahead of you in comprehension?

Canto: Details details. Small steps. One way of finding out all that is by asking them. At least such monitoring would give you some clues to go by. I look forward to this brave new transhumanising world….


Daniel Kahneman, Thinking fast and slow, 2012

Torres A and Hout M (2019) Pupils: A Window Into the Mind. Front. Young Minds. 7:3. doi: 10.3389/frym.2019.00003

Written by stewart henderson

June 24, 2019 at 11:18 am

On Massimo Pigliucci on scientism 2: brains r us

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neuroethics is coming…

In his Point of Inquiry interview, Pigliucci mentions Sam Harris’s book The Moral Landscape a couple of times. Harris seeks to make the argument, in that book, that we can establish, sometime in the future, a science of morality. That is, we can be factual about the good life and its opposite, and we can be scientific about the pathways, though there might be many, that lead towards the good life and away from the bad life. I’m in broad agreement about this, though for pragmatic reasons I would probably prefer the term ‘objective’ to ‘scientific’. Just because it doesn’t frighten the horses so much. As mentioned in my previous post, I don’t want to get hung up on terminology. Science obviously requires objectivity, but it doesn’t seem clear to everyone that morality requires objectivity too. I think that it does (as did, I presume, the authors of the Universal Declaration of Human Rights), and I think Harris argues cogently that it does, based on our well-being as a social species. But Pigliucci says this about Harris’s project:

When Sam Harris wrote his famous book The Moral Landscape, the subtitle was ‘How science can solve moral questions’ – something like that. Well that’s a startling question if you think about it because – holy crap! So I would assume that a typical reader would buy that book and imagine that now he’s going to get answers to moral questions such as whether abortion is permissible and in what circumstances, or the death penalty or something… And get them from say physics or chemistry, maybe neuroscience, since Harris has a degree in neuroscience..

Pigliucci makes some strange assumptions about the ‘typical reader’ here. Maybe I’m a long way from being a ‘typical reader’ (don’t we all want to think that?) but, to me the subtitle (which is actually ‘How science can determine human values’) suggests, again, methodology. By what methods, or by what means, can human value – that’s to say what is most valuable to human well-being – be determined. I would certainly not have expected, reading the actual sub-title, and considering the main title of the book, answers to specific moral questions. And I certainly wouldn’t expect answers to those questions to come from physics or chemistry. Pigliucci just mentions those disciplines to make Harris’s views seem more outrageous. That’s not good faith arguing. Neuroscience, however, is closer to the mark. Our brains r us, and if we want to know why a particular mammal behaves ‘badly’, or with puzzling altruism, studying the animal’s brain might be one among many places to start. And yet Pigliucci makes this statement later on re ‘scientistic’ scientists

It seems to me that the fundamental springboard for all this is a combination of hubris, the conviction that what they do is the most important thing – in the case of Sam Harris for instance, it turns out at the end of the book [The Moral Landscape] it’s not just science that gives you the answers, it’s neuroscience that gives you the answers. Well, surprise surprise, he’s a neuroscientist.

This just seems silly to me. Morality is about our thoughts and actions, which start with brain processes. Our cultural practices affect our neural processes from our birth, and even before our conception, given the cultural attitudes and behaviours of our future parents. It’s very likely that Harris completed his PhD in cognitive neuroscience because of his interest in human behaviour and its ethical consequences (Harris is of course known for his critique of religion, but there seems no doubt that his greatest concerns about religious belief are at base concerns about ethics). Yet according to Pigliucci, had Harris been a physicist he would have written a book on morality in terms of electromagnetic waves or quantum electrodynamics. And of course Pigliucci doesn’t examine Harris’s reasoning as to why he thinks science, and most particularly neuroscience and related disciplines, can determine human values. He appears to simply dismiss the whole project as hubristic and wrong-headed.

I know that I’m being a little harsh in critiquing Pigliucci based on a 20-minute interview, but there doesn’t seem any attempt, at least here, to explain why certain topics are or should be off-limits to science, except to infer that it’s obvious. Does he feel, for example, that religious belief should be off-limits to scientific analysis? If so, what do reflective non-religious people do with their puzzlement and wonder about such beliefs? And if it’s worth trying to get to the bottom of what cultural and psychological conditions bring about the neurological networking that disposes people to believe in a loving or vengeful omnipotent creator-being, it’s also worth trying to get to the bottom of other mind-sets that dispose people to behave in ways productive or counter-productive to their well-being. And the reason we’re interested isn’t just curiosity, for the point isn’t just to understand our human world, but to improve it.

Finally Pigliucci seems to confuse a lack of interest, among such people in his orbit as Neil deGrasse Tyson and Lawrence Krauss, in philosophy, especially as it pertains to science, with scientism. They’re surely two different things. It isn’t ‘scientism’ for a scientist to eschew a particular branch of philosophy any more than it is for her to eschew a different field of science from her own, though it might seem sometimes a bit narrow-minded. Of course, as a non-scientist and self-professed dilettante I’m drawn to those with a wide range of scientific and other interests, but I certainly recognise the difficulty of getting your head around quantum mechanical, legal, neurological, biochemical and other terminology (I don’t like the word ‘jargon’), when your own ‘rabbit hole’ is so fascinating and enjoyably time-consuming.

There are, of course, examples of scientists claiming too much for the explanatory power of their own disciplines, and that’s always something to watch for, but overall I think the ‘scientism’ claim is more abused than otherwise – ‘weaponised’ is the trendy term for it. And I think Pigliucci needs to be a little more skeptical of his own views about the limits of science.

Written by stewart henderson

May 26, 2019 at 3:09 pm

a discussion on scientific progress and scientism

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Pretty funny, but not much related to this post

Scientific progress depends on an expectation of continuous innovation, on encouraging an attitude of willingness to experiment, rejecting established authority of every sort, on the assumption that new experiments will bring out new realities and force us to revise our knowledge.’
Bruno Maçães, The Dawn of Eurasia

Discuss ‘scientific progress’ in the light of this statement.

Canto: This is very interesting. As a ‘fan’ (remembering that this word comes from ‘fanatic’) of scientific progress, an evidence junky, and also a humanist, I can see, and have experienced, a collision between the scientific process, which involves a respect for evidence rather than people, and the strongly held cultural/religious beliefs of people, which they hold fast to as identifying and solidifying principles. For example, the Aboriginal belief, handed down and taught, that their people have inhabited this land for eternity, while scientists are trying to determine precisely when the first home sapiens arrived here, and how old the continent of Australia actually is, given the pre-existence of Gondwana, Pangaea and the rest. 

Jacinta: A belief probably not held by that many Aboriginal people, most of whom have been educated in institutions that treat science seriously. That’s to say, more recent generations, and this is a problem everywhere – ‘established authority’ can also mean traditional beliefs and practices, even the old established language. The tribal language, the local language, being abandoned everywhere for more global forms of communication. 

Canto: Yes I read yesterday an essay topic about the growth of English as an international language, often as a person’s second or third language – and I recognised immediately that the essay was out of date as it stated that about 900,000 used English that way. It’s well over a billion now and rising fast. 

Jacinta: And the language of science is largely English – plus mathematics. It’s funny that there are actual scientific endeavours to preserve many of the 7,000 languages that exist in the world, while scientific communication relies largely on a universal single language…

Canto: Yes, and a person can feel that contradiction, that kind of tugging both ways, within themselves. Like following Scottish or Jewish traditions at times of celebration, enjoying the fun, and then thinking – why am I doing this? I don’t believe in first-footing or plate-breaking or whatever. 

Jacinta: People follow these traditions because they work, or at least they think so, but not always in the traditional way. And many such followers are well aware of this – that these activities don’t work as lucky charms so much as social glue. But that’s the trouble with glue – you get stuck. 

Canto: You’ve heard of the missionary who tried to Christianise the Andaman Islanders and was speared to death for his efforts? Most people’s responses were of the ‘serves him right’ type. But wasn’t that because the missionary was just trying to substitute one set of myths for another? If he was trying to introduce a new fishing method, or, I don’t know, something modernising and scientific…

Jacinta: We’ll have to get onto so-called ‘scientism’ at some stage, but here’s the thing. Maçães writes about ‘rejecting established authority of every sort’, and Richard Feynman apparently described science as belief in the ignorance of experts, but when we come upon, say, the Piripkura people of Brazil’s Mato Grosso, whose continued existence in the face of western diseases and cattle-raising gunmen we’re not even sure about, converting such people into scientific modernists who should question why they’re having difficulty surviving and adapting, seems very arrogant somehow. 

Canto: This is where humanism comes in, and it’s a fraught kind of humanism. Many would say – look, all these tribes will disappear, because their way of life is outdated and ‘in the way’, which doesn’t mean the people will disappear, they’ll gradually get absorbed into the broader population, modernised, urbanised, educated and homogenised into our diverse modern world. If they’re lucky enough not to die of disease and gunshot wounds. 

Jacinta: And their expertise in traditional hunting, gathering and fishing will be found to be not so much ignorant as obsolete within the mechanised world of food production and consumption. And this is happening everywhere, from the Limi of south-western China to the Bushmen of Botswana. Could it be said that they’re the victims of scientific progress? It’s hard to distinguish science and technology from other aspects of modernism I suppose, but this is the complex other face of science’s otherwise refreshing respect for innovation, experiment and evidence rather than ‘experts’, or just plain old people. 

Canto: So what do you think of ‘scientism’, which is I think a rather vague claim about the steamrolling arrogance of science, and what about the possibly self-destructive implications of relentless scientific advancement?

Jacinta: You know there might be something in the criticism, because as I try to get my head around the complexities of, say, electromagnetism, or neurological interactions, I find myself less drawn to some of my earlier loves, literature and the visual arts. I don’t know if that means I’m arrogantly dismissing them, but I do know they’re not engaging me in the old way. I find science more exciting, and maybe that’s dangerous…

Canto: In what way? 

Jacinta: Well, the motto of this blog is ‘rise above yourself and grasp the world’, but that kind of engagement – in something so large if not abstract as ‘the world’….

Canto: The world isn’t abstract – it’s everything. Everything found in time and space. It’s absolute reality. 

Jacinta: Well maybe, but that engagement in ‘everything’, it rather detaches you from the smaller world of the people around you, and – and yourself. Rising above yourself entails escaping from yourself and you can’t really do that, can you? 

Canto: The sciences of biology, neurology, genetics and so forth are the best ways of learning about ourselves. It all comes back to us in the end, doesn’t it? Our mathematical equations, our experiments, our discoveries of black holes, the Higgs boson, gravitational waves, they’re all about us, somehow. The things we do. And it seems it helps our understanding and sympathy. Science is about finding out things, like finding out about other people. The more we find out, the less we tend to dismiss or hate, or fear. Look at those who commit acts of terror. Surely ignorance plays a major role in such acts. A refusal or inability to find out stuff about others. A lack of curiosity about why people are different in the way they look and act. Science – or the scientific impulse, which is basically curiosity – opens us up to these things, so that we no longer hate or fear mosquitos or spiders or snakes or Christians or Moslems or Jews. 

Jacinta: Hmmm, so what’s the buzz about scientism? Let’s end this post by discussing a quote from an essay on scientism written for the American Association for the Advancement of Science:

It is one thing to celebrate science for its achievements and remarkable ability to explain a wide variety of phenomena in the natural world. But to claim there is nothing knowable outside the scope of science would be similar to a successful fisherman saying that whatever he can’t catch in his nets does not exist. Once you accept that science is the only source of human knowledge, you have adopted a philosophical position (scientism) that cannot be verified, or falsified, by science itself. It is, in a word, unscientific.

Canto: Well I’m not impressed with this argument, I must say, probably because I don’t agree with the implied definition of science it presents. Science, to me, is an activity, driven by curiosity, which provides dividends in the form of a greater knowledge which raises more and more questions. I rarely worry whether it’s the only source of human knowledge, because that raises the question of what ‘knowledge’ is, and I’m not so interested in that enquiry. Much more interesting to try and work out how life came from non-life, how our planet got covered in water, whether life of any kind exists elsewhere in the solar system, how different parts of the brain interact under particular circumstances, etc etc. I don’t know or care whether you call those enquiries ‘science’ or not, I only know that you won’t get answers to those questions by just sitting around thinking about them. I mean, you can start by thinking, forming a hypothesis, but then you have to explore, gather evidence, conduct experiments, test then modify or abandon your hypothesis…

Jacinta: I thought the ‘net’ analogy used in that quote was pretty inept. Of course it’s reminiscent of the old Kantian categories, the grid or net by means of which we know things, which separates the noumenal world of things in themselves from the phenomenal world of perception/conception. But Kant’s problem was that the noumenal world was just a hypothesis that couldn’t be tested, since we only have our perceptions/conceptions – enhanced somewhat by technology – with which to test things.

Canto: Probably another reason why so many scientists, especially physicists, seem dismissive of philosophers of science. Another problem with those that go on about scientism is that they insist that there are other ways of knowing, but you can rarely pin them down on what those ways of knowing are.

Jacinta: Yes they’re often religious or new-age types, and spiritual knowledge is their stock-in-trade. And if you don’t have that spirituality, which doesn’t need to be explained, then you’ll never understand, you’ll always be a shallow materialist. There’s no response to that view.

Canto: Yes, we’re obviously on the autism spectrum, though not so far along as real scientists. Meanwhile, let’s keep exploring…

Written by stewart henderson

April 15, 2019 at 9:27 am

fish deaths in the lower Darling – interim report

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Jacinta: We wrote about this issue in a piece posted on February 11, so it’s time to follow up – an interim report came out on February 20, and a final report is due at the end of March, but my feeling is that the final report won’t differ much from this interim one.

Canto: Yes I get the feeling that these experts have largely known about the situation for a long time – unusual climatic conditions plus an increasing lack of water in the system, which would make the remaining water more susceptible to extremes of weather.

Jacinta: So here’s some of what they’re saying. There were three separate events; the first on December 15 involved tens of thousands of fish deaths over a 30km stretch of the Darling near Menindee, the second on Jan 6-7, over 45kms in the same area, involved hundreds of thousands of deaths, even millions according to some residents, and the third on Jan 28, with thousands of deaths. Likely effects on fish populations in the Darling will last for years.

Canto: And they warn that more deaths are likely to occur – though no major events have been reported since – due to low inflows and continued dry conditions in the catchment area. Monitoring has shown that there are problems of low dissolved oxygen and ‘high stratification’ at various points along the river. I presume ‘high stratification’ is self-explanatory, that the water isn’t mixing due to low flows?

Jacinta: Yes, but I think the issue is thermal stratification, where you have a warm surface layer sitting above a cooler, oxygen-depleted sub-surface layer. These are excellent conditions for algal blooms apparently. And the low flows are a natural feature of the Darling. It’s also very variable in flow, much more so than the Murray, due to its low relief, the more variable rainfall in the region, and the tributaries which create a large catchment area. I don’t know if that makes sense.

Canto: Neither do I. I note that they’ve been carefully critical of the NSW government’s ‘Barwon-Darling Water Sharing Plan 2012’, because between the draft and final implementation of the plan the number of high-flow Class C shares was reduced and the number of Class A (low flow) and Class B (medium flow) shares increased, which meant more extraction of water overall, and at lower flows. They recognise that there have been recent Federal moves to reverse this, but clearly they don’t consider them sufficient.

Jacinta: Yes and the problem goes back a way. They refer to an analysis from almost two decades ago:

The flow regime in the lower Darling has changed significantly since the completion of the Menindee Lakes storage scheme in 1968, and as a result of abstractions in the Barwon–Darling and its tributaries. It is estimated that the mean annual flow in the Darling River has been reduced by more than 40% as a result of abstractions in the Barwon–Darling (Gippel & Blackham, 2002). 

Presumably ‘abstractions’ means what I think it means – though elsewhere they use the term ‘extractions’ which is confusing.

Canto: We should point out the immense complexity of the system we’re dealing with, which we can see from detailed maps that accompany the report, not to mention a number of barely comprehensible charts and graphs. Anyway the effect of ‘water management’ on native vegetation has been dire in some regions. For example, reduced inundation of natural floodplains has affected the health of the river red gums, while other trees have been killed off by the creation of artificial lakes.

Jacinta: And returning to fish deaths, the report states that ‘the influence of upstream extractions on inflows to the Menindee Lakes is an important consideration when assessing the causes of fish deaths downstream’. What they point out is that the proportion of extractions is higher in times of lower inflow, which is intuitively obvious I suppose. And extractions during 2017-8 were proportionally the second highest on record. That’s in the Northern Basin, well above the Menindee Lakes.

Canto: And the extractions have been mainly out of the tributaries above the Barwon-Darling, not those principal rivers. Queenslanders!

Jacinta: No mention of Queenslanders, but let’s not get bogged down..

Canto: Easily done when there’s hardly any water…

Jacinta: Let’s go to the provisional findings and recommendations. There are 18 briefly stated findings in all, and 20 more expansive recommendations. The first two findings are about extreme weather/climatic conditions amplified by climate change, with the expectation that this will be a continuing and growing problem. Findings 3 and 4 focus on the combined effects of drought and development. There’s a lack of updated data to separate out the effects, but it’s estimated that pre-development inflows into the Menindee Lakes were two or three times what they are now. Further findings are that the impact of diversions of or extractions from flows are greater during dry years, that extractions from tributaries are more impactful than extractions from the Barwon-Darling Rivers.

Canto: The findings related directly to fish deaths – principally findings 10 through 15 – are most interesting, so I’ll try to explain. The Menindee Lakes experienced high inflows in 2012 and 2016, which caused greater connection through the river system and better conditions for fish spawning and ‘recruitment’ (I don’t know what that means). So, lots of new, young fish. Then came the bad 2017-8 period, and releases from the Menindee Lakes were less than the minimum recommended under the water sharing plan, ‘with the intent to prolong stock and domestic requests to meet critical human needs’. So by the end of 2018, the high fish biomass became trapped or restricted between weirs, unable to move upstream or downstream. As the water heated up, significant algal blooms developed in the areas where fish had accumulated. Thermal stratification also occurred, with hypoxic (low oxygen) or anoxic (no oxygen) conditions in the lower waters, and algal blooms proliferating in the surface waters, where the fish were forced to hang out. Then conditions suddenly changed, with lower air temperatures and stormy conditions causing a rapid destratification. The low oxygen water – presumably more voluminous than the oxygenated water – dominated the whole water column and the fish had no way out.

Jacinta: Yes, you can’t adapt to such sudden shifts. The final findings are about existing attempts at fish translocation and aerating water which are having some success, about stratification being an ongoing issue, and about lack of knowledge at this preliminary stage of the precise extent of the fish deaths.

Canto: So now to the 20 recommendations. They’re grouped under 3 headings; preventive and restorative measures (1-9), management arrangements (10-13), and knowledge and monitoring (14-20). The report noted a lack of recent systematic risk assessment for low oxygen, stratification and blackwater (semi-stagnant, vegetation-rich water that looks like black tea) in the areas where the fish deaths occurred. There was insufficient or zero monitoring of high-risk areas for stratification, etc, and insufficient planning to treat problems as they arose. Flow management strategies (really involving reduced extraction) need to be better applied to reduce problems in the lower Darling. Reducing barriers to fish movement should be considered, though this is functionally difficult. Apparently there’s a global movement in this direction to improve freshwater fish stocks. Short term measures such as aeration and translocation are also beneficial. Funding should be set aside for research on and implementation of ecosystem recovery – it’s not just the fish that are affected. Long-term resilience requires an understanding of interactions and movement throughout the entire basin. Fish are highly mobile and restriction is a major problem. A whole-of system approach is strongly recommended. This includes a dynamic ‘active event-based management’ approach, especially in the upper reaches and tributaries of the Barwon-Darling, where extraction has been governed by passive, long-term rules. Such reforms are in the pipeline but now need to be fast-tracked. For example, ‘quantifying the volumes of environmental water crossing the border from Queensland to NSW…. would increase transparency and would help the CEWH [Commonwealth Environmental Water Holdings] with their planning, as well as clear the path to move to active management in Queensland’.

Jacinta: Right, you’ve covered most of the issues, so I’ll finish up with monitoring, measuring and reporting. The report argues that reliable, up-to-date accounting of flows, volumes in storage, extractions and losses due to seepage and evaporation are essential to create and maintain public confidence in system management, and this is currently a problem. Of course this requires funding, and apparently the funding levels have dropped substantially over the past decade. The report cites former funding and investment through the Co-operative Research Centre, Land and Water Australia and the National Water Commission, but ‘by the early 2010s, all of these sources of funding had terminated and today aggregate levels of funding have reduced to early 1980s levels, at a time when water was far less of a public policy challenge than it is today’.

Canto: We await the government’s response to that one.

Jacinta: And on fisheries research in particular, it has been largely piecemeal except when their was a concerted co-ordinated effort under the Native Fish Strategy, but the issue right now is to know how many fish (and other organisms) of the various affected species survived the event, which involves multi-level analyses, combined with management of Basin water balances, taking into account the ongoing effects of weather events due to climate change, in order to foster and improve the growth and well-being of fish stocks and freshwater habitats in general. Connectivity of the system in particular is a major concern of the report.

Canto: Right, so this has been a bit of a journey into the unknown for us, but a worthwhile one. It suggests that governments have been a bit dozey at the wheel in recent years, that extractions, especially in the upper reaches and tributaries, haven’t been well monitored or policed, and the connectivity of the system has suffered due to extractions, droughts and climate change. Funding seems to have dried up as much as some of the rivers have, and we’ll have to wait and see if this becomes an election issue. I suspect it’ll only be a minor one.

Written by stewart henderson

March 17, 2019 at 12:01 pm

kin selection – some fascinating stuff

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meerkats get together for ye olde family snap

Canto: So we’ve done four blogs on Palestine and we’ve barely scratched the surface, but we’re having trouble going forward with that project because, frankly, it’s so depressing and anger-inducing that it’s affecting our well-being.

Jacinta: Yes, an undoubtedly selfish excuse, but we do plan to go on with that project – we’re definitely not abandoning it, and meanwhile we should recommend such books as Tears for Tarshiha by the Palestinian peace activist Olfat Mahmoud, and Goliath by the Jewish American journalist Max Blumenthal, which highlight the sufferings of Palestinian people in diaspora, and the major stresses of trying to exist under zionist monoculturalism. But for now, something completely different, we’re going to delve into the fascinating facts around kin selection, with thanks to Robert Sapolski’s landmark book Behave. 

Canto: The term ‘kin selection’ was first used by John Maynard Smith in the early sixties but it was first mooted by Darwin (who got it right about honey bees), and its mathematics were worked out back in the 1930s. 

Jacinta: What’s immediately interesting to me is that we humans tend to think we alone know who our kin are, especially our extended or most distant kin, because only we know about aunties, uncles and second and third cousins. We have language and writing and record-keeping, so we can keep track of those things as no other creatures can. But it’s our genes that are the key to kin selection, not our brains.

Canto: Yes, and let’s start with distinguishing between kin selection and group selection, which Sapolsky deals with well. Group selection, popularised in the sixties by the evolutionary biologist V C Wynne-Edwards and by the US TV program Wild Kingdom, which I remember well, was the view that individuals behaved, sometimes or often, for the good of the species rather than for themselves as individuals of that species. However, every case that seemed to illustrate group selection behaviour could easily be interpreted otherwise. Take the case of ‘eusocial’ insects such as ants and bees, where most individuals don’t reproduce. This was seen as a prime case of group selection, where individuals sacrifice themselves for the sake of the highly reproductive queen. However, as evolutionary biologists George Williams and W D Hamilton later showed, eusocial insects have a unique genetic system in which they are all more or less equally ‘kin’, so it’s really another form of kin selection. This eusociality exists in some mammals too, such as mole rats. 

Jacinta: The famous primatologist Sarah Hrdy dealt something of a death-blow to group selection in the seventies by observing that male langur monkeys in India commit infanticide with some regularity, and, more importantly, she worked out why. Langurs live in groups with one resident male to a bunch of females, with whom he makes babies. Meanwhile the other males tend to hang around in groups brooding instead of breeding, and infighting. Eventually, one of this male gang feels powerful enough to challenge the resident male. If he wins, he takes over the female group, and their babies. He knows they’re not his, and his time is short before he gets booted out by the next tough guy. Further, the females aren’t ovulating because they’re nursing their kids. The whole aim is to pass on his genes (this is individual rather than kin selection), so his best course of action is to kill the babs, get the females ovulating as quickly as possible, and impregnate them himself. 

Canto: Yes, but it gets more complicated, because the females have just as much interest in passing on their genes as the male, and a bird in the hand is worth two in the bush…

Jacinta: Let me see, a babe in your arms is worth a thousand erections?

Canto: More or less precisely. So they fight the male to protect their infants, and can even go into ‘fake’ estrus, and mate with the male, fooling the dumb cluck into thinking he’s a daddy. 

Jacinta: And since Hrdy’s work, infanticide of this kind has been documented in well over 100 species, even though it can sometimes threaten the species’ survival, as in the case of mountain gorillas. So much for group selection.

Canto: So now to kin selection. Here are some facts. If you have an identical twin your genome is identical with hers. If you have a full sibling you’re sharing 50% and with a half-sibling 25%. As you can see, the mathematics of genes and relatedness can be widened out to great degrees of complexity. And since this is all about passing on all, or most, or some of your genes, it means that ‘in countless species, whom you co-operate with, compete with, or mate with depends on their degree of relatedness to you’, to quote Sapolsky. 

Jacinta: Yes, so here’s a term to introduce and then fairly promptly forget about: allomothering. This is when a mother of a newborn enlists the assistance of another female in the process of child-rearing. It’s a commonplace among primate species, but also occurs in many bird species. The mother herself benefits from an occasional rest, and the allomother, more often than not a younger relation such as the mother’s kid sister, gets to practice mothering. 

Canto: So this is part of what is called ‘inclusive fitness’, where, in this case, the kid gets all-day mothering (if of varying quality) the kid sister gets to learn about mothering, thereby increasing her fitness when the time comes, and the mother gets a rest to recharge her batteries for future mothering. It’s hopefully win-win-win. 

Jacinta: Yes, there are negatives and positives to altruistic behaviour, but according to Hamilton’s Rule, r.B > C, kin selection favours altruism when the reproductive success of relatives is greater than the cost to the altruistic individual. 

Canto: To explain that rule, r equals degree of relatedness between the altruist and the beneficiary (aka coefficient of relatedness), B is the benefit (measured in offspring) to the recipient, and C is the cost to the altruist. What interests me most, though, about this kin stuff, is how other, dumb primates know who is their kin. Sapolsky describes experiments with wild vervet monkeys by Dorothy Cheney and Robert Seyfarth which show that if monkey A behaves badly to monkey B, this will adversely affect B’s behaviour towards A’s relatives, as well as B’s relatives’ behaviour to A, as well as B’s relatives’ behaviour to A’s relatives. How do they all know who those relatives are? Good question. The same researchers proved this recognition by playing a recording of a juvenile distress call to a group of monkeys hanging around. The female monkeys all looked at the mother of the owner of that distress call to see what she would do. And there were other experiments of the sort. 

Jacinta: And even when we can’t prove knowledge of kin relations (kin recognition) among the studied animals, we find their actual behaviour tends always to conform to Hamilton’s Rule. Or almost always… In any case there are probably other cues, including odours, which may be unconsciously sensed, which might aid in inclusive fitness and also avoiding inbreeding. 

Canto: Yes and It’s interesting how this closeness, this familiarity, breeds contempt in some ways. Among humans too. Well, maybe not contempt but we tend not to be sexually attracted to those we grow up with and, for example, take baths with as kids, whether or not they’re related to us. But I suppose that has nothing to do with kin selection. And yet…

Jacinta: And yet it’s more often than not siblings or kin that we have baths with. As kids. But getting back to odours, we have more detail about that, as described in Sapolski. Place a mouse in an enclosed space, then introduce two other mice, one unrelated to her, another a full sister from another litter, never encountered before. The mouse will hang out with the sister. This is called innate recognition, and it’s due to olfactory signatures. Pheromones. From proteins which come from genes in the major histocompatibility complex (MHC). 

Canto: Histowhat?

Jacinta: Okay, you know histology is the study of bodily tissues, so think of the compatibility or otherwise of tissues that come into contact. Immunology.  Recognising friend or foe, at the cellular, subcellular level. The MHC, this cluster of genes, kicks off the production of proteins which produce pheromones with a unique odour, and because your relatives have similar MHC genes, they’re treated as friends because they have a similar olfactory signature. Which doesn’t mean the other mouse in the enclosure is treated as a foe. It’s a mouse, after all. But other animals have their own olfactory signatures, and that’s another story. 

Canto: And there are other forms of kin recognition. Get this – birds recognise their parents from the songs sung to them before they were hatched. Birds have distinctive songs, passed down from father to son, since its mostly the males that do the singing. And as you get to more complex species, such as primates – though maybe they’re not all as complex as some bird species – there might even be a bit of reasoning involved, or at least consciousness of what’s going on. 

Jacinta: So that’s kin selection, but can’t we superior humans rise above that sort of thing? Australians marry Japanese, or have close friendships with Nigerians, at least sometimes. 

Canto: Sometimes, and this is the point. Kinship selection is an important factor in shaping behaviour and relations, but it’s one of a multiple of factors, and they all have differential influences in different individuals. It’s just that such influences may go below the level of awareness, and being aware of the factors shaping our behaviour is always the key, if we want to understand ourselves and everyone else, human or non-human.

Jacinta: Good to stop there. As we’ve said, much of our understanding has come from reading Sapolsky’s Behave, because we’re old-fashioned types who still read books, but I’ve just discovered that there’s a whole series of lectures by Sapolsky, about 25, on human behaviour, which employs the same structure as the book (which is clearly based on the lectures), and is available on youtube here. So all that’s highly recommended, and we’ll be watching them.


R Sapolski, Behave: the biology of humans at our best and worst. Bodley Head, 2017