Archive for the ‘memory’ Category
the best kind of sleep
Canto: So Dr Seheult tells us that the most important sleep is in the earliest period. This is called slow-wave sleep or N3 sleep. It doesn’t last long, maybe half an hour…
Jacinta: Why is it called N3 sleep?
Canto: Well, here’s the detail – you have three stages of this early sleep. N1 is when you fall asleep. It lasts no more than ten minutes generally until you’re really there, in sleep. Then there’s N2 of course, which lasts from 30-60 minutes, your muscles relax and you begin to enter this slow-wave, also called delta-wave or delta brain activity sleep. That’s the deepest sleep of the night, at its deepest in the N3 period.
Jacinta: Well that explains the 1-2-3, sort of, but what about the N?
Canto: I haven’t been able to find that out specifically, but these are all phases of NREM (non-rapid eye movement) sleep, which are followed by the REM phase. So I think the N is just short for NREM. Anyway there are two types of sleep for maintaining good health – slow wave sleep and REM sleep towards the end of the night…
Jacinta: But don’t those two make up the whole of the sleep cycle?
Canto: Let me tell the story. Slow wave sleep is when you secrete valuable growth hormone, vital for children, in the time before midnight, according to the good doctor.
Jacinta: But I virtually never sleep before midnight.
Canto: Well you’re not alone there. In cities now, which are growing ever larger, we’re going to bed later and getting up earlier, and so sleeping less…
Jacinta: But generally living longer. So what’s the problem? I’ve heard that Hong Kong, which is about as urban as it gets, has the longest life expectancy on Earth – but that was probably measured before the China crackdown haha.
Canto: Well it’s no joke that China’s thugocracy will jeopardise everything in HK’s future, but good public healthcare and a very low infant mortality rate helps. People today can still live well with diabetes, obesity and slow-developing cancers, but they’d be even better with good sleep habits, if the rat-race allows them. But cities present us with a kind of eternal daylight, at great cost, not only in electric lighting, but in lack of sleep. Not to mention brightly lit screens that we take to bed with us…
Jacinta: Okay so what are the other benefits of slow wave and REM sleep, however delayed?
Canto: Dr Seheult describes a study showing that general sleep deprivation actually reduces the levels of antibodies produced after influenza vaccination. That’s to say, vaccination is less effective for the sleep-deprived. Another study used rhinovirus, a common cold virus. They paid students to be infected and found that those with good sleep efficiency, that’s to say, a high ratio of in-bed time to sleep time – their risk of being infected was reduced five to seven-fold, an extraordinary result. Actually this ‘extraordinary result’ finding comes up again and again in Matthew Walker’s book.
Jacinta: Yes, but it’s surely good to be awake sometimes too. But again, what is it about slow-wave and REM sleep that provides such benefits. What are the mechanisms?
Canto: Well, we’re talking about N3 sleep, the deepest sleep. This sleep phase is particularly important for memory consolidation, the stabilisation of a memory trace once it’s been acquired – meaning presumably the event itself, or its impact. It’s also called sleep-dependent memory processing. Now, how this precisely works is still being researched, but it appears to have much to do with interactions between neurons or neuronal complexes in the neocortex and the hippocampus. So here I should introduce sleep spindles, which are essential to all mammalian species.
Jacinta: They’re brainwaves, aren’t they?
Canto: Neural oscillations, indeed. They’re generated in the thalamic reticular nucleus (TRN), in richest quantities during N2 and N3 sleep. Wikipedia tells me this:
The density of spindles has been shown to increase after extensive learning of declarative memory tasks and the degree of increase in stage 2 spindle activity correlates with memory performance.
This is confirmed in experiments described in Why we sleep, showing that people who slept for a night between being asked to memorise certain data, like putting a name to a face, did a significantly better job than those who tried to remember the data after eight hours without sleep (from morning to evening). During the sleep period, subjects’ brain waves were recorded, and this is Dr Walker’s account:
The memory refreshment was related to lighter, stage 2 NREM sleep, and specifically the short, powerful bursts of electrical activity called sleep spindles… The more sleep spindles an individual obtained during the nap, the greater the restoration of their learning when they woke up. Importantly, sleep spindles did not predict someone’s innate learning aptitude. That would be a less interesting result, as it would imply that inherent learning ability and spindles simply go hand in hand. Instead, it was specifically the change in learning from before relative to after sleep, which is to say the replenishment of learning ability, that spindles predicted.
Jacinta: So they were correlating the number of spindles with their memorising performance, and memory here is being equated with learning. Is that right? I mean, is learning really just memorising?
Canto: Well, no, but it helps. I’m trying to memorise Newton’s inverse square law for gravity, but I know that even if I can reel it off like a favourite poem that doesn’t mean I fully understand it. Let me see G = m1.m2 over r². I’m not sure if that’s right.
Jacinta: Yeah, basically you have to know that the gravitational attraction between two bodies is equal to the product of their masses divided by the square of the distance between their ‘centres of mass’. I think. Though why that happens to be the case I have no idea. Does anyone?
Canto: Because… the universe? I’m beginning to feel sleepy…
References
M. Walker, Why we sleep, 2017
https://www.uofmhealth.org/health-library/hw48331
How to get the best sleep for your immune system | Roger Seheult (video)
https://www.oal.cuhk.edu.hk/cuhkenews_202101_life_expectancy/
reading matters 9
New Scientist – the collection: mysteries of the human brain. 2019
- content hints – history of neurology, Galen, Hippocrates, Descartes, Galvani, Thomas Willis, Emil Du Bois-Reymond, Santiago Ramon y Cajal, connectionism, plasticity, mind-maps, forebrain, midbrain, hindbrain, frontal, parietal and occipital lobes, basal ganglia, thalamus, hypothalamus, amygdala, hippocampus, cerebral cortex, substantia nigra, pons, cerebellum, medulla oblongata, connectome, action potentials, axons and dendritic spines, neurotransmitters, axon terminals, signalling, ion channels and receptors, deep brain stimulation, transcranial direct current stimulation, hyper-connected hubs, 170,000 kilometres of nerve fibres, trains of thought, unbidden thoughts, memory and imagination, the sleeping brain, unconscious activity, the role of dreams, brainwaves during sleep, sleep cycles, traumatic stress disorder, Parkinsons, ADHD, dementia, depression, epilepsy, anaesthesia, attention, working memory, first memories, rationality, consciousness, von Economo neurons, the sense of self…
the strange world of the self-described ‘open-minded’ – part one
my copy – a stimulating and fun read, great fodder for closed-minded types, comme moi
I’ve just had my first ever conversation with someone who at least appears to be sceptical of the Apollo 11 moon landing of 1969 – and, I can only suppose, the five subsequent successful moon landings. Altogether, twelve men walked on the moon between 20 July 1969 and December 10 1972, when the crew members of Apollo 17 left the moon’s surface. Or so the story goes.
This conversation began when I said that perhaps the most exciting world event I’ve experienced was that first moon landing, watching Neil Armstrong possibly muffing the lines about one small step for a man, and marvelling that it could be televised. I was asked how I knew that it really happened. How could I be so sure?
Of course I had no immediate answer. Like any normal person, I have no immediate, or easy, answer to a billion questions that might be put to me. We take most things on trust, otherwise it would be a very very painstaking existence. I didn’t mention that, only a few months before, I’d read Phil Plait’s excellent book Bad Astronomy, subtitled Misconceptions and misuses revealed, from astrology to the moon landing ‘hoax’. Plait is a professional astronomer who maintains the Bad Astronomy blog and he’s much better equipped to handle issues astronomical than I am, but I suppose I could’ve made a fair fist of countering this person’s doubts if I hadn’t been so flabbergasted. As I said, I’d never actually met someone who doubted these events before. In any case I don’t think the person was in any mood to listen to me.
Only one reason for these doubts was offered. How could the lunar module have taken off from the moon’s surface? Of course I couldn’t answer, never having been an aeronautical engineer employed by NASA, or even a lay person nerdy enough to be up on such matters, but I did say that the moon’s minimal gravity would presumably make a take-off less problematic than, say, a rocket launch from Mother Earth, and this was readily agreed to. I should also add that the difficulties, whatever they might be, of relaunching the relatively lightweight lunar modules – don’t forget there were six of them – didn’t feature in Plait’s list of problems identified by moon landing skeptics which lead them to believe that the whole Apollo adventure was a grand hoax.
So, no further evidence was proffered in support of the hoax thesis. And let’s be quite clear, the claim, or suggestion, that the six moon landings didn’t occur, must of necessity be a suggestion that there was a grand hoax, a conspiracy to defraud the general public, one involving tens of thousands of individuals, all of whom have apparently maintained this fraud over the past 50 years. A fraud perpetrated by whom, exactly?
My conversation with my adversary was cut short by a third person, thankfully, but after the third person’s departure I was asked this question, or something like it: Are you prepared to be open-minded enough to entertain the possibility that the moon landing didn’t happen, or are you completely closed-minded on the issue?
Another way of putting this would be: Why aren’t you as open-minded as I am?
So it’s this question that I need to reflect on.
I’ve been reading science magazines on an almost daily basis for the past thirty-five years. Why?
But it didn’t start with science. When I was kid, I loved to read my parents’ encyclopaedias. I would mostly read history, learning all about the English kings and queens and the battles and intrigues, etc, but basically I would stop at any article that took my fancy – Louis Pasteur, Marie Curie, Isaac Newton as well as Hitler, Ivan the Terrible and Cardinal Richelieu. Again, why? I suppose it was curiosity. I wanted to know about stuff. And I don’t think it was a desire to show off my knowledge, or not entirely. I didn’t have anyone to show off to – though I’m sure I wished that I had. In any case, this hunger to find things out, to learn about my world – it can hardly be associated with closed-mindedness.
The point is, it’s not science that’s interesting, it’s the world. And the big questions. The question – How did I come to be who and where I am? – quickly becomes – How did life itself come to be? – and that extends out to – How did matter come to be? The big bang doesn’t seem to explain it adequately, but that doesn’t lead me to imagine that scientists are trying to trick us. I understand, from a lifetime of reading, that the big bang theory is mathematically sound and rigorous, and I also know that I’m far from alone in doubting that the big bang explains life, the universe and everything. Astrophysicists, like other scientists, are a curious and sceptical lot and no ‘ultimate explanation’ is likely to satisfy them. The excitement of science is that it always raises more questions than answers, it’s the gift that keeps on giving, and we have human ingenuity to thank for that, as we’re the creators of science, the most amazing tool we’ve ever developed.
But let me return to open-mindedness and closed-mindedness. During the conversation described above, it was suggested that the USA simply didn’t have the technology to land people on the moon in the sixties. So, ok, I forgot this one: two reasons put forward – 1, the USA didn’t have the technological nous; 2, the modules couldn’t take off from the moon (later acknowledged to be not so much of an issue). I pretty well knew this first reason to be false. Of course I’ve read, over the years, about the Apollo missions, the rivalry with the USSR, the hero-worship of Yuri Gagarin and so forth. I’ve also absorbed, in my reading, much about spaceflight and scientific and technological development over the years. Of course, I’ve forgotten most of it, and that’s normal, because that’s how our brains work – something I’ve also read a lot about! Even the most brilliant scientists are unlikely to be knowledgeable outside their own often narrow fields, because neurons that fire together wire together, and it’s really hands-on work that gets those neurons firing.
But here’s an interesting point. I have in front of me the latest issue of Cosmos magazine, issue 75. I haven’t read it yet, but I will do. On my shelves are the previous 74 issues, each of which I’ve read, from cover to cover. I’ve also read more than a hundred issues of the excellent British mag, New Scientist. The first science mag I ever read was the monthly Scientific American, which I consumed with great eagerness for several years in the eighties, and I still buy their special issues sometimes. Again, the details of most of this reading are long forgotten, though of course I learned a great deal about scientific methods and the scientific mind-set. The interesting point, though, is this. In none of these magazines, and in none of the books, blogs and podcasts I’ve consumed in about forty years of interest in matters scientific, have I ever read the claim, put forward seriously, that the moon landings were faked. Never. I’m not counting of course, books like Bad Astronomy and podcasts like the magnificent Skeptics’ Guide to the Universe, in which such claims are comprehensively debunked.
The SGU podcast – a great source for exciting science developments, criticism of science reporting, and debunking of pseudo-science
Scientists are a skeptical and largely independent lot, no doubt about it, and I’ve stated many times that scepticism and curiosity are the twin pillars of all scientific enquiry. So the idea that scientists could be persuaded, or cowed into participating in a conspiracy (at whose instigation?) to hoodwink the public about these landings is – well let’s just call it mildly implausible.
But of course, it could explain the US government’s massive deficit. That’s it! All those billions spent on hush money to astronauts, engineers, technicians (or were they all just actors?), not to mention nosey reporters, science writers and assorted geeks – thank god fatty Frump is here to make America great again and lift the lid on this sordid scenario, like the great crusader against fake news that he is.
But for now let’s leave the conspiracy aspect of this matter aside, and return to the question of whether these moon landings could ever have occurred in the late sixties and early seventies. I have to say, when it was put to me, during this conversation, that the technology of the time wasn’t up to putting people on the moon, my immediate mental response was to turn this statement into a question. Was the technology of the time up to it? And this question then turns into a research project. In other words, let’s find out, let’s do the research. Yay! That way, we’ll learn lots of interesting things about aeronautics and rocket fuel and gravitational constraints and astronaut training etc, etc – only to forget most of it after a few years. Yet, with all due respect, I’m quite sure my ‘adversary’ in this matter would never consider engaging in such a research project. She would prefer to remain ‘open-minded’. And if you believe that the whole Apollo project was faked, why not believe that all that’s been written about it before and since has been faked too? Why believe that the Russians managed to get an astronaut into orbit in the early sixties? Why believe that the whole Sputnik enterprise was anything but complete fakery? Why believe anything that any scientist ever says? Such radical ‘skepticism’ eliminates the need to do any research on anything.
But I’m not so open-minded as that, so in my dogmatic and doctrinaire fashion I will do some – very limited – research on that very exciting early period in the history of space exploration. I’ll report on it next time.
on a big jet plane
This morning I did something I’ve never done in my entire adult life, and I’m nearly 58. I got into an aeroplane which went into the sky. It took me to Melbourne from Adelaide. From there I caught another plane to Canberra, where I’m writing this in the city’s YHA.
I was anxious about this flight. I have a guilty secret, I’m an addict of Air Crash Investigations, so I’m semi-expert on the many things that can go wrong on an aircraft and I’ve had very little experience of a plane arriving safely at its destination.
I did travel on a plane at 14, from Adelaide to Kangaroo Island and back again – about an hour’s travel all up. Today’s journeys weren’t much longer, but of course it’s the take offs and landings that are the major killers.
I do realise that air travel is the safest mode available. I’m about the only person I know who hasn’t travelled by plane dozens of times without being the worse for it, but that’s not much consolation when you strap yourself into your tight little economy seat and note how flimsy everything looks, how thin the barrier between yourself and the outside air – air which, I soon learn, is 37000 metres above solid ground.
While we were walking through one of those moveable corridors that led directly to the aircraft’s front door I could see the pilot and his apprentice (had he earned his Ps?) chatting in the cockpit (strange word for a space designed to bring thousands of travellers though thousands of kilometres of high sky). I was shocked at how vulnerable they looked sitting there so prominently forward in what I think is called the nose-cone, which looked horribly fragile, like a glass egg that could be cracked by any passing bird. I’d expected something more like the bridge of the starship Enterprise, or that mysterious intergalactic vessel that Carl Sagan peered out of in Cosmos.
I was also a bit shocked at how bus-like the interior was, with its densely packed seating and narrow central aisle. Of course this was no jumbo jet – do they use that term nowadays? – but even so… and then I was shocked again, as we taxied to the runway, that I could feel the bumps on the road, as if we really were in a taxi, with suspension issues. through the window I could see the plane’s right wing bouncing and shuddering. It wasn’t screwed on properly! I was having a little joke with myself, but I wasn’t amused. I glanced around at the other passengers. One was reading a magazine, another was yawning ostentatiously. I had a book in my lap – Will Storr’s The heretics: adventures with the enemies of science – but this time it was just for show. It just wouldn’t do to behave like a gawping schoolboy, though that was exactly what I was doing. And to be fair to my benumbed self, even the sad circumstances of schizophrenics and Morgellons sufferers seemed to pale in comparison to my life and death situation.
We moved off from the airport lights into the pre-dawn dimness. I wasn’t going to see much of this takeoff, I’d have to rely on feeling. Someone over the intercom was saying, in his most reassuring voice, that the weather in Melbourne was pretty dismal, suggesting problems with the landing. Oh my. On the runway, everything suddenly got loud. The rockets had launched, or something, and then we were off the ground, I could tell by the lights falling away beneath me.
Dawn was breaking. Soon I could see clearly the mass of Lake Alexandrina, with Lake Albert attached like a suckling pup. I knew it well from so many maps, and I thought of those great mapmakers Jim Cook and Matt Flinders, how amazed they would’ve been at seeing such grand features, that would’ve taken them weeks to survey, set before them in an instant. But then the plane veered off, tilting at an angle that no bus would ever survive, and again I glanced around at my fellow passengers to check if it was okay to panic. all was blandness, and when the plane finally righted itself I gazed down – and due to the cloud cover I had to look down as near as perpendicular as possible to see much land at all – at a whole array of fascinating but unrecognisable features. I tried to fix them in my memory so I could check them on a map later – I love maps. But would they appear on a map? Were we still flying over South Australia or had we crossed the border? Was I being too obsessional? Of what use would be such knowledge? Well, bearing in mind Bertrand Russell’s nice essay on useless knowledge, I had some thoughts on airlines doing a running commentary on the sights and scenes on the ground, synced to flight-paths, one for each side of the street, so to speak, and played through headphones, which you could take or leave; but the logistics of it, considering variations of flight-path and speed of flight, and the probable lack of interest, considering the bored or otherwise absorbed expressions of my fellow passengers, would be too much for cost-conscious airliners.
Within a few minutes I was shocked – yet again – to hear that we’d soon be arriving in Melbourne. Someone said over the intercom that conditions remained miserable and that, hopefully, everything would be okay. There was more tilting and veering, and I tried to make out the familiar shape of Port Phillip Bay but we were too close to the ground. In any case I soon became concerned with something altogether different, something which was much more of a problem on my return flight to Adelaide (I’m writing the rest of this up at home, three more flights later). My ears began to ache, building up to some intensity until suddenly there was an unblocking, like the burst of a bubble, and only then did I realise that the pain was localised to one ear. After that, all was fine, but on the return trip there was no bubble-burst, and the pain reached an excruciating level, leaving me moaning and whimpering and desperate for relief. The problem was, of course, aerosinusitis, which I’ll deal with in my next post.
The lego blocks of the CBD came and went on the window screen and I could soon see the airstrips of Tullamarine. The landing was slightly bumpy but nothing untoward, and I was looking forward to a pleasant coffee break and possibly breakfast in ‘Melbourne’, before the connecting flight to Canberra.
No way José. A quick check of our tickets (yes we really didn’t check them before this) told us that the other flight was leaving just as we were arriving. How could they do this to us? But if we ran or – don’t panic – walked very fast, we just might… then we noticed it wasn’t a departure but a check-in time, yet even so… And in fact, after some long striding through long stretches of airport we got there just in time for boarding. Thank god I didn’t need a toilet break, and it was just as well we didn’t have an hour to spare considering airport prices – the medium latte I bought at Adelaide airport, which I had to gulp down just before boarding, cost me $5.30, an all-time record.
The Canberra trip was anti-climactic, in spite of the bogey word ‘turbulence’, so much featured on Air Crash Investigations. Not only was I a vastly more experienced traveller, but this time there was nothing to see landwise, nothing but whiter-than-white clouds from horizon to horizon, like a fluffy Antarctica. Only as we descended below the cloud line near Canberra – and this flight was even shorter than the first one – did I get to see something familiar, the forested slopes of the Snowies, where once I did some memorable bush-walking, attacked by march flies and leeches and coming face-to-face, for a fleeting instant, with a black snake.
After a near-perfect landing, nothing more to report, my innocence of flying had slipped away forever. How ironic that Virgin airlines should deprive me of my virginity in this area. From now on I can blend in with all the rest, almost without pretending. There’s something almost sad about it, a tiny loss of identity, or a replacement for some part of me that I’m not quite sure about. But hey, we all know the self is an illusion.
the latest on dolphin language
I wrote, or semi-podcasted, on the brain of the dolphin a while back, and much of my focus was on language, often described as the sine qua non of cerebral complexity and intelligence. In that piece, posted about eight months ago, I reported that there there was little clear evidence of any complex language in dolphins, but there had been some interesting research. Allow me to quote myself:
Dolphins do sometimes mimic the whistles of other dolphins too, particularly those of their closest relatives, but signature whistles as a form of recognition and differentiation, are a long way from anything like language. After all, many species can recognise their own mates or kin from the distinctive sounds they make, or from their specific odour, or from visual cues. However, a clever experiment carried out more recently, which synthesised these whistles through a computer, so that the whistle pattern was divorced from its distinctive sound, found that the dolphins responded to these patterns even when produced via a different sound. It seemed that they were recognising names. It’s undoubtedly intriguing, but clearly a lot more research is required.
So it was with some interest that I heard, on a recent SGU podcast, an account of what seemed an elaboration of the experiments conducted above, further confirming that dolphins recognised names. Or were they just reporting the same experiments? Having re-listened to the SGU segment, I find that they didn’t give any details of who did the study they were talking about, the only mention was to a news article. So I’ll just report on anything I can find, because it’s such a cool subject.
There’s a nice TED talk, from February 2013, on dolphin language and intelligence here, which is about researches over many years in the Bahamas with Atlantic spotted dolphins. As always, I suggest you listen to the talk and do the ‘research on the research’ yourself, as I’m not a scientist and I’m only doing this to educate myself, but hopefully I can also engage your interest.
Dolphins have a brain- to-body ratio (a rough but not entirely reliable guide to intelligence) second only to humans, they pass the mirror self-awareness test (another standard for intelligence that’s been questioned recently), they can be made to understand very basic artificial human language tests, and they’re at least rudimentary tool users. But the real interest lies in their own, obviously complex, vocal communication systems.
I probably misrepresented the information on signature whistles before: they’re only what we humans have been able to isolate from all the ‘noise’ dolphins make, because they’re recognisable and interpretable to us. Denise Herzing, in her TED talk, refers to ‘cracking the code’ of dolphins’ communication systems. She and her team have been working with the dolphins over the summer months for 28 years. They work with underwater cameras and hydrophones to correlate the sounds and behaviours of their subjects. This particular species is born without spots, but is fully black-and-white spotted by age 15. They go through distinct developmental phases making them easy to track over the years (dolphins live into their early 50s). The distinctive spotted patterns make them easy to track individually. Females are sexually mature by about age 9, males at around 15. Dolphins are very sexually active with multiple partners, so paternity is not always easy to determine, so this is worked out by collecting fecal matter and analysing its DNA. So, over 28 years, three generations have been tracked.
What really interests me about the dolphin communication question is their relation to sound and their use of sound compared to ours. Herzing describes them as ‘natural acousticians’ who make and hear sounds ten times as high as humans do. They also have highly developed vision, so they communicate via bodily signals, and they have taste and touch. Sound is of course a wave or vibration which can be felt in water, the acoustic impedance of tissue in water being much the same as on land. Tickling, of a kind, does occur.
Signature whistles are the most studied dolphin sounds, as the most easily measured. They’re used as names, in connecting mothers and calves for example. But there are many other vocalisations, such as echo-location clicks (sonar), used in hunting and feeding, and also socially, in tightly-packed sound formations – buzzes, which can be felt in the water. They’re used regularly by males courting females. Burst-pulse sounds are used in times of conflict, and they are the least studied, most hard to measure of dolphin sounds.
Interestingly, Herzing notes that there’s a lot of interaction and co-operation in the Bahamas between spotted and bottle-nose dolphins, including baby-sitting each others’ calves, and combining to chase away sharks, but little mention is made, in this talk at least, of any vocal communication between the two species. When she goes on to talk about synchrony, I think she’s only talking about within-species rather than between species. Synchrony is a mechanism whereby the dolphins co-ordinate sounds and body postures to create a larger, stronger social unit.
As I’ve mentioned, dolphins make plenty of sounds beyond the range of human hearing. Underwater equipment is used to collect these ultrasonic sounds, but we’ve barely begun to analyse them. Whistle complexity has been analysed through information theory, and is highly rated even in relation to human languages, but virtually nothing is known about burst-pulse sounds, which, on a spectrogram, bear a remarkable similarity to human phonemes. Still, we have no Rosetta Stone for interpreting them, so researchers have developed a two-way interface, with underwater keyboards, with both visual and audible components. In developing communication, they’ve exploited the dolphins’ natural curiosity and playfulness. Dolphins, for example, are fond of mimicking the postures and vocalisations of humans, and invite the researchers into their play. Researchers have developed artificial whistles to refer to dolphins’ favourite toys, including sargassum, a kind of seaweed, and ropes and scarves, so that they can request them via the keyboard interface. These whistles were outside the dolphins’ normal repertoire, but easily mimicked by them. The experiment has been successful, but of course it isn’t known how much they understand, or what’s going through their minds with all this. What is clear, however, is that the dolphins are extremely interested in and focused on this type of activity, which sometimes goes on for hours.
This research group has lately been using an underwater wearable computer, known as CHAT (cetacean hearing and telemetry), which focuses on acoustic communication. Sounds are created via a forearm keyboard and an underwater speaker for real-time Q and A. This is still at the prototype stage, but it uses the same game-playing activity, seeking to empower dolphins to request toys, as well as human game-players, through signature whistles. It’s hoped that the technology will be utilisable for other species too in the future.
All of this is kind of by way of background to the research reported on recently. This was really about dolphin memory rather than language – or perhaps more accurately, memory triggered by language. Dolphins recognise the sounds of each others’ signature whistles, but would they recognise the whistle of a dolphin they’d not been in contact with for years. And for how many years? Researcher Jason Bruck tested this by collecting whistles of dolphins in captive facilities throughout the US. Dolphins are moved around a lot, and lose contact with friends and family. Sounds a bit like the foster-care system. Bruck found that when dolphins heard the signature whistles of old companions played to them through an underwater speaker, they responded with great attention and interest. One dolphin was able to recognise the whistle of a friend from whom he was separated at age two, after twenty years’ separation. As biologist Janet Mann put it, this is a big breakthrough but not so surprising, as dolphins are highly social animals whose lives, like ours, are criss-crossed by profound connections with others, with effects positive, negative and equivocal. It’s important, too, for what it suggests – the capacity to remember so much more, in the same coded way. in other words, a complex language, perhaps on a level with ours. Will we ever get to crack this code? Why not. Hopefully we won’t stop trying.