Tag: synapses

How much damage can a couple of molecules do?

Just how dangerous is Novichok?

Keith S. Taber

"We are only talking about molecules here…

There might be a couple of molecules left in the Salisbury area. . ."

Expert interviewed on national news

The subject of chemical weapons is not to be taken lightly, and is currently in the news in relation to the Russian invasion of Ukraine, and the concern that the limited progress made by the Russian invaders may lead to the use of chemical or biological weapons to supplement the deadly enough effects of projectiles and explosives.

Organophosphorus nerve agents (OPNA) were used in Syria in 2013 (Pita, & Domingo, 2014), and the Russians have used such nerve agents in illicit activities – as in the case of the poisoning of Sergey Skripal and his daughter Yulia in Salisbury. Skripal had been a Russian military intelligence officer who had acted for the British (i.e., as a double agent), and was convicted of treason – but later came to the UK in a prisoner swap and settled in Salisbury (renown among Russian secret agents for its cathedral). 1

Salisbury, England – a town that featured in the news when it was the site of a Russian 'hit' on a former spy (Image by falco from Pixabay )

These substances are very nasty,

OPNAs are odorless and colorless [and] act by blocking the binding site of acetylcholinesterase, inhibiting the breakdown of acetylcholine… The resulting buildup of acetylcholine leads to the inhibition of neural communication to muscles and glands and can lead to increased saliva and tear production, diarrhea, vomiting, muscle tremors, confusion, paralysis and even death

Kammer, et al., 2019, p.119

So, a substance that occurs normally in cells, but is kept in check by an enzyme that breaks it down, starts to accumulate because the enzyme is inactivated when molecules of the toxin bind with the enzyme molecules stopping them binding with acetylcholine molecules. Enzymes are protein based molecules which rely for their activity on complex shapes (as discussed in 'How is a well-planned curriculum like a protein?' .)

Acetylcholine is a neurotransmitter. It allows signals to pass across synapses. It is important then that acetylcholine concentrations are controlled for nerves to function (Image source: Wikipedia).

Acetylcholinesterase is a protein based enzyme that has an active site (red) that can bind and break up acetylcholine molecules (which takes about 80 microseconds per molecule). The neurotransmitter molecule is broken down into two precursors that are then available to be synthesised back into acetylcholine when appropriate. 2

Toxins (e.g., green, blue) that bind to the enzyme's active site block it from breaking down acetylcholine.

(Image source: RCSB Protein Data Bank)

A need to clear up after the release of chemical agents

The effects of these agents can be horrific – but, so of course, can the effects of 'conventional' weapons on those subjected to aggression. One reason that chemical and biological weapons are banned from use in war is their uncontrollable nature – once an agent is released in an environment it may remain active for some time – and so hurt or kill civilians or even personnel from the side using those weapons if they move into the attacked areas. The gases used in the 1912-1918 'world' war, were sometimes blown back towards those using them when the wind changed direction.

Image by Eugen Visan from Pixabay 

This is why, when small amounts of nerve agents were used in the U.K. by covert Russian agents to attack their targets, there was so much care put into tracing and decontaminating any residues in the environment. This is a specialised task, and it is right that the public are warned to keep clear of areas of suspected contamination. Very small quantities of some agents can be very harmful – depending upon what we mean by such relative terms as 'small'. Indeed, two police officers sent to the scene of the crime became ill. But what does 'very small quantities' mean in terms of molecules?

A recent posting discussed the plot of a Blakes7 television show episode where a weapon capable of destroying whole planets incorporated eight neutrons as a core component. This seemed ridiculous: how much damage can eight neutrons do?

But, I also pointed out that, sadly, not all those who watched this programme would find such a claim as comical as I did. Presumably, the train of thought suggested by the plot was that a weapon based on eight neutrons is a lot more scary than a single neutron design, and neutrons are found in super-dense neutron stars (which would instantly crush anyone getting too near), so they are clearly very dangerous entities!

A common enough misconception

This type of thinking reflects a common learning difficulty. Quanticles such as atoms, atomic nuclei, neutrons and the like are tiny. Not tiny like specs of dust or grains of salt, but tiny on a scale where specs of dust and grains of salt themselves seem gigantic. The scales involves in considering electronic charge (i.e., 10-19C) or neutron mass (10-27 kg) can reasonably be said to be unimaginatively small – no one can readily visualise the shift in scale going from the familiar scale of objects we normally experience as small (e.g., salt grains), to the scale of individual molecules or subatomic particles.

People therefore commonly form alternative conceptions of these types of entities (atoms, electrons, etc.) being too small to see, but yet not being so far beyond reach. It perhaps does not help that it is sometimes said that atoms can now be 'seen' with the most powerful microscopes. The instruments concerned are microscopes only by analogy with familiar optical microscopes, and they produce images, but these are more like computer simulations than magnified images seen through the light microscope. 3

It is this type of difficulty which allows scriptwriters to refer to eight neutrons as being of some significance without expecting the audience to simply laugh at the suggestion (even if some of us do).

An expert opinion

Although television viewers might have trouble grasping the insignificance of a handful of neutrons (or atoms or molecules), one would expect experts to be very clear about the vast difference in scale between us (people for example) and them (nanoscopic entities of the molecular realm). Yet experts may sometimes be stretched beyond their expertise without themselves apparently being aware of this – as when a highly qualified and experienced medical expert agreed with an attorney that the brain sends out signals to the body faster than the speed of light. If a scientific expert in a high profile murder trial can confidently make statements that are scientifically ridiculous then this underlines just how challenging some key scientific ideas are.

For any of us, knowing what we do not know, recognising when we are moving outside out of areas where we have a good understanding, is challenging. Part of the reason that student alternative conceptions are so relevant to science learning is that a person's misunderstanding can seem subjectively to be just as well supported, sensible, coherent and reasonable as a correct understanding. Where a teacher themself has an alternative conception (which sometimes happens, of course) they can teach this with as much enthusiasm and confidence as anything they understand canonically. Expertise always has limitations.

A chemical weapons expert

I therefore should not have been as surprised as I was when I heard a news broadcast featuring an expert who was considered to know about chemical weapons refer to the potential danger of "a couple of molecules". This was in relation to the poisoning by Russian agents of the Salisbury residents,

"During an interview on a BBC Radio 4 news programme (July 5th, 2018), Hamish de Bretton-Gordon, who brands himself as one of the world's leading chemical weapons experts, warned listeners that there may be risks to the public due to residue from the original incident in the area. Whilst that may have been the case, his suggestion that "we are only talking about molecules here. . .There might be a couple of molecules left in the Salisbury area. . ." seemed to suggest that even someone presented to the public as a chemistry expert might completely fail to appreciate the submicroscopic scale of individual molecules in relation to the macroscopic scale of a human being."

Taber, 2019, p.130
Chemical weapons expert ≠ chemistry expert

Now Colonel de Bretton-Gordon is a visiting fellow at  Magdalene College Cambridge, and the College website describes him as "a world-leading expert in Chemical and Biological weapons". I am sure he is, and I would not seek to underplay the importance of decontamination after the use of such agents; but if someone who has such expertise would assume that a couple of molecules of any substance posed a realistic threat to a human being with its something like 30 000 000 000 000 cells, each containing something like 40 000 000 molecules of protein (to just refer to one class of cellular components), then it just underlines how difficult it is to appreciate the gulf in scale between molecules and men.

Regarding samples of nerve agents, they may be deadly even in small quantities, but that still means a lot of molecules.

Novichok cocktails

The attacks in Salisbury (from which the intended victims recovered, but another person died in nearby Amesbury apparently having come into contact with material assumed to have been discarded by the criminals), were reported to have used 'Novichok', a label given to group of compounds.

"Based on analyses carried out by the British "Defence Science and Technology Laboratory" in Porton Down it was concluded that the Skripals were poisoned by a nerve agent of the so-called Novichok group. Novichok … is the name of a group of nerve agents developed and produced by Russia in the last stage of the Cold War."

Carlsen, 2019, p.1

Testing of toxins is often based on the LD50 – which means finding the dose that has an even chance of being lethal. This is not an actual amount, as clearly the amount of material that is needed to kill a large adult will be more than that to kill a small child, but the amount of the toxin needed per unit mass of victim. Although no doubt these chemicals have been directly tested on some poor test specimens of non-consenting small mammals, such information is not in the public domain.

Indeed, being based on state secrets, there is limited public data on Novichok and related agents. Carlsen (2019) estimates the LD50 for oral administration of 9 compounds in the Novichok group and some closely related agents to vary between 0.1 to 96.16 mg/kg.

Carlsen suggest the most toxic of these compounds is one known as VX. VX was actually first developed by British Scientists, although almost equivalent nerve agents were later developed elsewhere, including Russia.

'Chemical structures of V-agents.'
(Figure 2 from Nepovimova & Kuca, 2018 – subject to http://creativecommons.org/licenses/BY-NC-ND/4.0/)
n.b. This figure shows more than a couple of molecules of nerve agent – so might this be a lethal dose?

Carlsen then argues that the actual compounds in Novachok are probably less toxic than XV, which might explain…

"…why did the Skripals not die following expose to such high potent agents; just compare to the killing of Kim Jong-nam on February 13, 2017 in Kuala Lumpur International Airport, where he was attacked by the highly toxic VX, and died shortly after."

Carlsen, 2019, p1

So, for the most sensitive agent, known as XV (LD50 c. 0.1 mg/kg), a person of 50 kg mass would it is estimated have a 50% chance of being killed by an oral dose of 0.1 x 50 mg. That is 5 mg or 0.005 g by mouth. A single drop of water is said to have a volume of about 0.05 ml, and so a mass of about 0.05 g. So, a tenth of a drop of this toxin can kill. That is a very small amount. So, if as little as 0.005 g of a nerve agent will potentially kill you then that is clearly a very toxic substance.

The molecular structure of XV is given in the figure above taken from Nepovimova and Kuca (2018). These three structures shown appear to be isomeric – that is the three molecules are structural isomers. They would have the same empirical formula (and the same molecular mass).

Chemical shorthand

This type of structural formula is often used for complex organic molecules as it is easy for experts to read. It is one of many special types of representation used in chemistry. It is based on the assumption that most organic compounds can be understood as if substituted hydrocarbons. (They may or may not be derived that way – this is jut a formalism used as a thinking tool.) Hydrocarbons comprise chains of carbon atomic cores bonded to each other, and with their other valencies 'satisfied' by being bonded to hydrogen atomic cores. These compounds can easily be represented by lines where each line shows the bond between two carbon atomic cores. The hydrogen centres are not shown at all, but are implicit in the figure (they must be there to 'satisfy' the rules of valency – i.e., carbon centres in a stable structures nearly always have four bonds ).

Anything other than carbon and hydrogen is shown with elemental symbols, and in most organic compounds these other atomic centres take up on a minority of positions in the structure. So, for compounds, such as the 'VX' compounds, these kinds of structural representations are a kind of hybrid, with some atomic centres shown by their elemental symbols – but others having to be inferred.

From the point of view of the novice learner, this form of abstract representation is challenging as carbon and hydrogen centres need to be actively read into the structure (whereas an expert has learnt to do this automatically). But for the expert this type of representation is useful as complex organic molecules can contain hundreds or thousands of atomic centres (e.g., the acetylcholinesterase molecule, as represented above) and structural formulae that show all the atomic centres with elemental symbols would get very crowded.

So, below I have annotated the first version of XV:

The VX compound seems to have a molecular mass of 267

This makes the figure much more busy, but helps me count up the numbers of different types of atomic centres present and therefore work out the molecular mass – which, if I had not made a mistake, is 267. I am working here with the nearest whole numbers, so not being very precise, but this is good enough for my present purposes. That means that the molecule has a mass of 267 atomic mass units, and so (by one of the most powerful 'tricks' in chemistry) a mole of this compound, the actual substance, would have a mass of 267g.

The trick is that chemists have chosen their conversion factor between molecules and moles, the Avogadro constant of c. 6.02 x 1023, such that adding up atomic masses in a molecule gives a number that directly scales to grammes for the macroscopic quantity of choice: the mole. 5

So, if one had 267 g of this nerve agent, that would mean approximately 6.02 x 1023 molecules. Of course here we are talking about a much smaller amount – just 0.005 g (0.005/267, about 0.000 02 moles) – and so many fewer molecules. Indeed we can easily work out 0.005 g contains something like

(0.005 / 267) x 6.02 x 1o23 = 11 273 408 239 700 374 000 = 1×1019 (1 s.f.)

That is about

10 000 000 000 000 000 000 molecules

So, because of the vast gulf in scale between the amount of material we can readily see and manipulate, and the individual quanticle such as a molecule, even when we are talking about a tiny amount of material, a tenth of a drop, this still represent a very, very large number of molecules. This is something chemistry experts are very aware of, but most people (even experts in related fields) may not fully appreciate.

The calculation here is approximate, and based on various estimates and assumptions. It may typically take about 10 000 000 000 000 000 000 molecules of the most toxic Novichok-like agent to be likely to kill someone – or this estimate could be seriously wrong. Perhaps it takes a lot more, or perhaps many fewer, molecules than this.

But even if this estimate is out by several orders of magnitude and it 'only' takes a few thousand million million molecules of XV for a potential lethal dose, that can in no way be reasonably described as "a couple of molecules".

It takes very special equipment to detect individual quanticles. The human retina is in its own way very sophisticated, and comes quite close to being able to detect individual photons – but that is pretty exceptional. As a rule of thumb, when anyone tells us that a few molecules or a few atoms or a few ions or a few electrons or a few neutrons or a few gamma rays or… can produce any macroscopic effect (that we can see, feel, or notice) we should be VERY skeptical.

Work cited:
Notes:

1 Two men claiming to be the suspects whose photographs had been circulated by the British Police, and claimed by the authorities here to be Russian military intelligence officers, appeared on Russian television to explain they were tourists who had visited Salisbury sightseeing because of the Cathedral.

2 According to the RCSB Protein Data Bank website

"Acetylcholinesterase is found in the synapse between nerve cells and muscle cells. It waits patiently and springs into action soon after a signal is passed, breaking down the acetylcholine into its two component parts, acetic acid and choline."

Molecule of the month: Acetylcholinesterase

Of course, it does not 'wait patiently': that is anthropomorphism.

3 We might think it is easy to decide if we are directly observing something, or not. But perhaps not:

"If a chemist heats some white powder, and sees it turns yellow, then this seems a pretty clear example of direct observation. But what if the chemist was rightly conscious of the importance of safe working, and undertook the manipulation in a fume cupboard, observing the phenomenon through the glass screen. That would not seem to undermine our idea of direct observation – as we believe that the glass will not make any difference to what we see. Well, at least, assuming that suitable plane glass of the kind normally used in fume cupboards has been used, and not, say a decorative multicoloured glass screen more like the windows found in many churches. Assuming, also, that there is not bright sunlight passing through a window and reflecting off the glass door of the fume cupboard to obscure the chemist's view of the powder being heated. So, assuming some basic things we could reasonably expect about fume cupboards, in conjunction with favourable viewing conditions, and taking into account our knowledge of the effect of plane glass, we would likely not consider the glass screen as an impediment to something akin to direct observation.

Might we start to question an instance of direct observation if instead of looking at the phenomenon through plane glass, there was clear, colourless convex glass between the chemist and the powder being heated? This might distort the image, but should not change the colours observed. If the glass in question was in the form of spectacle lenses, without which the chemist could not readily focus on the powder, then even if – technically – the observations were mediated by an instrument, this instrument corrects for a defect of vision such that our chemist would feel that direct observation is not compromised by, but rather requires, the glasses.

If we are happy to consider the bespectacled chemist is still observing the phenomenon rather than some instrumental indication of it, then we would presumably feel much the same about an observation being made with a magnifying glass, which is basically the same technical fix as the spectacles. So, might we consider observation down a microscope as direct observation? Early microscopes were little more than magnifying glasses mounted in stands. Modern compound microscopes use more than one lens. A system of lenses (and some additional illumination, usually) reveals details not possible to the naked eye – just as the use of convex spectacles allow the longsighted chemist to focus on objects that are too close to see clearly when unaided.

If the chemist is looking down the microscope at crystal structures in a polished slice of mineral, then, it may become easier to distinguish the different grains present by using a Polaroid filter to selectively filter some of the light reaching the eye from the observed sample. This seems a little further from what we might normally think of as direct observation. Yet, this is surely analogous to someone putting on Polaroid sunglasses to help obtain clear vision when driving towards the setting sun, or donning Polaroid glasses to help when observing the living things at the bottom of a seaside rock pool on a sunny day when strong reflections from the surface prevent clear vision of what is beneath.

A further step might be the use of an electron microscope, where the visual image observed has been produced by processing the data from sensors collecting reflections from an electron beam impacting on the sample. Here, conceptually, we have a more obvious discontinuity although the perceptual process (certainly if the image is of some salt crystal surface) may make this seem no different to looking down a powerful optical microscope. An analogy here might be using night-vision goggles that allow someone to see objects in conditions where it would be too dark to see them directly. I have a camera my late wife bought me that is designed for catching images of wildlife and that switches in low light conditions to detecting infrared. I have a picture of a local cat that triggered an image when the camera was left set up in the garden overnight. The cat looks different from how it would appear in day-light, but I still see a cat in the image (where if the camera had taken a normal image I would not have been able to detect the cat as the image would have appeared like the proverbial picture of a 'black cat in a coal cellar'). Someone using night-vision goggles considers that they see the fox, or the escaped convict, not that they see an image produced by electronic circuits.

If we accept that we can see the cat in the photograph, and the surface details of crystal grains in the electron microscope image, then can we actually see atoms in the STM [scanning tunneling microscope] image? There is no cat in or on my image, it is just a pattern of pixels that my brain determines to represent a cat. I never saw the cat directly (I was presumably asleep) so I have no direct evidence there really was a cat if I do not accept the photograph taken using infrared sensors. I believe there are cats in the world, and have seen uninvited cats in my garden in daylight, and think the camera imaged one of them at night. So it seems reasonable I am seeing a cat in the image, and therefore I might wonder if it is reasonable to doubt that I can also see atoms in an STM image.

One could shift further from simple sensory experience. News media might give the impression that physicists have seen the Higgs boson in data collected at CERN. This might lead us to ask: did they see it with their eyes? Or through spectacles? Or using a microscope? Or with night-vision goggles? Of course, they actually used particle detectors.

Feyerabend suggests that if we look at cloud chamber photographs, we do not doubt that we have a 'direct' method of detecting elementary particles …. Perhaps, but CERN were not using something like a very large cloud chamber where they could see the trails of condensation left in the 'wake' of a passing alpha particle, and that could be photographed for posterity. The detection of the Higgs involved very sophisticated detectors, complex theory about the particle cascades a Higgs particle interaction might cause, and very complex simulations to allow for all kinds of issues relating to how the performance of the detectors might vary (for example as they age) and how a signal that might be close to random noise could be identified…. No one was looking at a detector hoping to see the telltale pattern that would clearly be left by a Higgs, and only a Higgs. In one sense, to borrow a phrase, 'there's nothing to see'. Interpreting the data considered to provide evidence of the Higgs was less like using a sophisticated microscope, and more like taking a mixture of many highly complex organic substances, and – without any attempt to separate them – running a mass spectrum, and hoping to make sense of the pattern of peaks obtained.

Taber, 2019, pp.158-160

4 That is not to suggest that one should automatically assume that one molecule of a toxin can only ever damage one protein molecule somewhere in one body cell. After all, one of the reasons that CFCs (chlorofluorocarbons, which used to be used as propellants in all kinds of spray cans for example) were so damaging to the ozone 'layer' was because they could initiate a chain reaction.

In reactions that involve free radicals, each propagation step can produce another free radical to continue the reaction. Eventually two free radicals are likely to interact to terminate the process – but that might only be after a great many cycles, and the removal of a great many ozone molecules from the stratosphere. However, even if one free radical initiated the destruction of many molecules of ozone, that would still be a very small quantity of ozone, as molecules are so tiny. The problem was of course that a vast number of CFC molecules were being released.

5 So one mole of hydrogen gas, H2, is 2g, and so forth.

My brain can multitask even if yours makes a category error

Do not mind the brain, it is just doing its jobs

Keith S. Taber

Can Prof. Dux's brain really not multitask?

I was listening to a podcast where Professor Paul Dux of the University of Queensland said something that seemed to me to be clearly incorrect – even though I think I fully appreciated his point.

"why the brain can't multitask is still very much a topic of considerable debate"

Prof. Paul Dux
Is it true that brains cannot multitask? I think mine can. (Image by Gerd Altmann from Pixabay) 

The podcast was an episode of the ABC radio programme All in the Mind (not to be confused with the BBC radio programme All in the Mind, of course) entitled 'Misadventures in multitasking'

"All in the Mind is an exploration of the mental: the mind, brain and behaviour — everything from addiction to artificial intelligence." An ABC radio programme and podcast.

The argument against multitasking

Now mutlitasking is doing several things at once – such as perhaps having a phone conversation whilst reading an unrelated email. Some aspects of the modern world seem to encourage this – such as being queued on the telephone (as when I was kept on hold for over an hour waiting to get an appointment at my doctor's surgery – I was not going to just sit by the phone in the hope I would eventually get to the top of the queue). Similarly 'notifications' that seek to distract us from what we are doing on the computer, as if anything that arrives is likely to be important enough for us to need immediate alerting, add little to the sum of human happiness.1

Now I have heard the argument against multitasking before. The key is attention. We may think we are doing several things at once, but instead of focusing on one activity, completing, it, then shifting to another, what multitaskers actually do is continuously interrupt their focus on one activity to refocus attention on the another. The working memory has limited capacity (this surely is what limits our ability to reflectively multitask?), and we can only actually focus on one activity at a time, so multitasking is a con – we may think we are being more productive but we are not.

Now, people do tire, and after, say 45 minutes at one task it may be more effective to break, do something unrelated, and come back to your work fresh. If you are writing, and you break, and take the washing out of the machine and hang it up to dry, and make a cup of tea, and then come back to your writing fifteen or twenty minutes later, this is likely to be ultimately more productive than just ploughing on. You have been busy, not just resting, but a very different kind of activity, and your mind (hopefully) is refreshed. If you have been at your desk for 90 minutes without a break, then go for a walk, or even a quick lie down.

That however, is very different from doing your writing, as you check your email inbox, and keep an eye on a social media feed, and shop online. You can only really do one of those things at a time and if you try to multitask you are likely to quickly tire, and make mistakes as you keep interrupting your flow of concentration. (So, if you have been doing your writing, and you feel the need to do something else, give yourself a definite period of time to completely change activity, and then return fully committed to the writing.)

Now, I find that line of argument very convincing and in keeping my with own experience. (Which is not to say I always follow my own advice, of course.) Yet, I still thought Prof. Dux was wrong. And, indeed, there is one sense in which I would like to think deliberate reflective multitasking is not counterproductive.

If your brain cannot multitask you'd perhaps better hope it focuses on breathing

The brain is complex…

This is a short extract from the programme,

Paul Dux: Why the brain can't multitask is still very much a topic of considerable debate because we have these billions of neurons, trillions of synaptic connections, so why can't we do two simple things at once?

Sana Qadar: This is Professor Paul Dux, he's a psychologist and neuroscientist at the University of Queensland. He takes us deeper into what's going on in the brain.

Paul Dux: A lot of people would say it's because we have these capacities for attention. The brain regions that are involved in things like attention are our lateral prefrontal cortex. You have these populations of neurons that respond to lots of different tasks and multiple demands. That of course on one hand could be quite beneficial because it means that we are able to learn things quickly and can generalise quickly, but maybe the cost of that is that if we are doing two things at once in close temporal proximity, they try to draw on the same populations of neurons, and as a result leads to interference. And so that's why we get multitasking costs.

Sana Qadar: Right, so that's why if you are doing dishes while chatting to a friend, a dish might end up in the fridge rather than the cupboard where it's supposed to go.

Paul Dux: That's right, exactly.

Paul Dux talking to Sana Qadar who introduces 'All in the mind'

Now I imagine that Prof. Dux is an expert, and he certainly seemed authoritative. Yet, I sensed a kind of concept-creep, that led to a category error, here.

A category error

A category error is where something is thought of or discussed as though a member of an inappropriate class or category. A common example might be gender and sex. At one time it was widely assumed that gender (feminine-masculine) was directly correlated to biological sex (female-male) so terms were interchangeable. It is common to see studies in the literature which have looked for 'sex differences' when it seems likely that the researchers have collected no data on biological sex.

Models that suggest that the 'particles' (molecules, ions, atom) in a solid are touching encourage category errors among learners: that such quanticles are like tiny marbles that have a definite surface and diameter. This leads to questions such as whether on expansion the particles get larger or just further apart. (Usually the student is expected to think that the particles get further apart, but it is logically more sensible to say they get larger. But neither answer is really satisfactory.)

If someone suggested that a mushroom must photosynthesise because that is how plants power their metabolism then they would have made a category error. (Yes, plants photosynthesise. However, a mushroom is not a plant but a fungus, and fungi are decomposers.)

The issue here, to my mind (so to speak) was the distinction between brain (a material object) and conscious mind (the locus of subjective experience). Whilst it is usually assumed that mind and brain are related (and that mind may arise, emerge from processes in the brain) they may be considered to relate to different levels of description. So, mind and brain are not just different terms for the same thing.

Mind might well arise from brain, but it is not the same kind of thing. So, perhaps the notion of 'tasks' applies to minds, not brains? (Figure from Taber, 2013)

So, it is one thing to claim that the mind can only be actively engaged in one task at a time, but that is not equivalent to suggesting this is true of the brain that gives rise to that mind.2

Prof. Dax seemed to be concerned with the brain:

"the brain…billions of neurons, trillions of synaptic connections… brain regions…lateral prefrontal cortex…populations of neurons"

Yet it seems completely unfounded to claim that human brains do not multitask as we surely know they do. Our brains are simultaneously processing information from our eyes, our ears, our skin, our muscles, etc. This is not some kind of serial process with the brain shifting from one focus to another, but is parallel processing, with different modules doing different things at the same time. Certainly, we cannot give conscious attention to all these inputs at once, so the brain is filtering and prioritising which signals are worth notifying to head office (so to speak). We are not aware of most of this activity – but then that is generally the case with our brains.

The brain controls the endocrine system. The brain stem has various functions, including regulating breathing and heart rate and balance. If the brain cannot multitask we had perhaps better hope it focuses on breathing, although even then I doubt we would survive for long based on that activity alone.

Like the proverbial iceberg, most of our brain activity takes place below the waterline, out of conscious awareness. This is not just the physiological regulation – but a lot of the cognitive processing. So, we consolidate memories and develop intuitions and have sudden insights because our brains are constantly (but preconsciously) processing new data in the light of structures constructed through past experience.

If you are reading, you may suddenly notice that the room has become cold, or that the doorbell is ringing. This is because although you were reading (courtesy of your brain), your brain was also monitoring various aspects of the environment to keep alert for a cue to change activity. You (as in a conscious person, a mind if you like) may not be able to do two things at once, so your reading is interrupted by the door bell, but only because your brain was processing sensory information in the background whilst it was also tracking the lines of text in your book, and interpreting the symbols on the page, and recalling relevant information to provide context (how that term was defined, what the author claimed she was going to demonstrate at the start of the chapter…). Your mind as the locus of your conscious experience cannot multi-task, certainly, and certainly "brain regions that are involved in…attention" are very relevant to that, but your brain itself is still a master of multitasking.

Me, mybrain, and I

So, if the brain can clearly multitask, can we say that the person cannot multitask?

That does not seem to work either. The person can thermoregulate, digest food, grow hair and nails, blink to moisten the eye etc., etc as they take an examination or watch a film. These are automatic functions. So, might we say that it is the body, not the person carrying out those physiological functions? (The body of the person, but not the person, that is.)

Yet, most people (i.e., persons) can hold a conversation as they walk along, and still manage to duck under an obstruction. The conversation requires our direct attention, but walking and swerving seem to be things which we can do on 'autopilot' even if not automatic like our heartbeat. But if there was a complex obstruction which required planning to get around, then the conversation would likely pause.

So, it is not the brain, the body, or even the person that cannot multitask, but more the focus of attention, the stream of consciousness, the conscious mind. Perhaps confusion slips in because these distinctions do not seem absolute as our [sic] sense of identify and embodiment can shift. I kick out (with my leg), but it is my leg which hurts, and perhaps my brain that is telling me it is hurting?

Figure by  by mohamed Hassan from Pixabay; background by  by Sad93 from Pixabay 

Meanwhile, my other brain was relaxing

There is also one sense in which I regularly multitask. I listen to music a lot. This includes, usually, when I am reading. And, usually, when I am writing. I like to think I can listen to music and work. (But Prof. Dux may suggest this is just another example of how humans "are not actually good at knowing our own limitations".)

I like to think it usually helps. I also know this is not indiscriminate. If I am doing serious reading I do not play music with lyrics as that may distract me from my reading. But sometimes when I am writing I will listen to songs (and, unfortunately for anyone in earshot, may even find I am singing along). I also know that for some activities I need to have familiar music and not listen to something new if the music is to support rather than disturb my activity.

Perhaps I am kidding myself, and am actually shifting back and forth between

being distracted from my work by my musicandfocusing on my work and ignoring the music.

I know that certainly sometimes is the case, but my impression is that usually I am aware of the music at a level that does not interfere with my work, and sometimes the music both seems to screen out extraneous noise and even provides a sense of flow and rhythm to my thinking.

The human brain has two somewhat self-contained, but connected, hemispheres. (Image by Gerd Altmann from Pixabay)

I suspect this has something to do with brain lateralisation and how, in a sense, we all have two brains (as the hemispheres are to some extent autonomous). Perhaps one of my hemispheres is quietly (sic) enjoying my music whilst the other is studiously working. I even fancy that my less verbal hemisphere is being kept on side by being fed music and so does not get bored (and so perhaps instigate a distracting daydream) whilst it waits for the other me, its conjoined twin, to finish reading or writing.

I may well be completely wrong about that.

Perhaps I am just as hopeless at multitasking with my propensity to attempt simultaneous scholarship and music appreciation as those people who think they can monitor social media whilst effectively studying.3 Perhaps it is just an excuse to listen to music when I should be working.

But even if that is so, I am confident my brain can multitask, even if I cannot.

Work cited:
Note:

1 The four minute warning, perhaps. But,

  • Apple are releasing a new iPhone next spring?
  • Another email has arrived inviting me to talk at some medical conference on a specialism I cannot even pronounce?
  • A fiend of a friend of a friend has posted some update on social media that I can put into Google translate if I can be bothered?
  • Someone I do not recall seems to have a job anniversary?
  • Someone somewhere seems to have read something I once wrote (and I can find out who and where for a fee)?

Luckily I have been notified immediately as now I know this I will obviously no longer wish to complete the activity I was in the middle of.

2 One could argue that when a person is conscious (be that awake, or dreaming) one task the brain is carrying out is supporting that conscious experience. So, anything else a brain of a conscious person is doing must be an additional task. Perhaps, the problem is that minds carry out tasks (which suggests an awareness of purpose), but brains are just actively processing?

3 As a sporting analogy for the contrast I am implying here, there is a tradition in England of attending international cricket matches, and listening to the 'test match special' commentary (i.e., verbal) on the radio while watching (i.e. visual) the match. This seems to offer complementary enhancement of the experience. But I have also often seen paying spectators on televised football matches looking at their mobile phones rather than watching the match.