Review : The Brain

I interrupt my mythology book reviews to turn to the completely different matter of neuroscience.

David Eagleman's Livewired was one of my favourite reads of recent years. He put forward a genuinely technologically optimistic study that has absolutely sod-all to do with that stupid manifesto, and felt like a much-needed counterweight to the equally stupid "all technological innovation is crap" cynicism which seems to pervade social media. He also explored things philosophically, claiming that it is a actually possible for us to experience new qualia. 

I've mentioned Livewired a few times over the years and it's my shame that I never did a review of it. I think I'm going to have to re-read it to do it justice.

Anyway, his earlier, shorter book The Brain was an obvious read. The major theme of Livewired was the brain's tremendous adaptability, how it could repurpose itself to accomplish new tasks with old hardware. Eagleman did a very thorough job of describing just how far this could go, setting out both when surprising levels of flexibility were possible but also when limits would be reached. 

There are plenty of obvious overlaps between these two books. Since The Brain covers these much more concisely, perhaps by covering them in brief here, I can shorten my eventual review of Livewired... which would otherwise risk just rewriting the whole damn book, 'cos it was bloody good.

The Brain is a very good, very short read. I give it 8/10 for being such an excellent but little compendium on how the brain works. It doesn't tie itself down in unnecessary caveats or tangents but doesn't skip the uncertainties either. It just gets on with things, so so will I.

Semi-permanent plasticity

Brain development, says Eagleman, continues roughly up to the age of 25 or so. Sure, the earliest years are important (in Livewired he makes a bit more of this, noting that certain very basic skills are almost impossible to develop once out of childhood, e.g. feral children will never fully integrate into society), but much happens throughout adolescence and early adulthood too. New connections are formed and discarded as they prove useful or unhelpful (I believe in Livewired he describes this as a process of babbling).

Teenagers brains, he says, are literally different from adults, just as children are. They're socially awkward risk-takers not just because of lack of experience, but also because of their neurology (though of course, presumably experience plays a large role in shaping their neural structures). They are, paradoxically, emotionally hypersensitive but also prone to seeking out highly emotional activities, and unable to control their emotional responses as much as adults are. In one experiment they got physically anxious when asked to sit in a shop window but at the same time they send each other naked pictures of themselves*. They are quite literally immature.

* Not literally at the same time, you understand.

But that's not the end of the story at all. If all the major wiring is in place by around 25, substantial redevelopment is still possible indefinitely afterwards, at least for re-using old networks in new ways. Sufficient practise at a skill can cause macroscopic changes in the brain basically at any age; in Livewired he says this can occur in a matter of hours.

This plasticity, claims Eagleman, is unique to humans. Most animals rely much more on hardwired instincts*. Human adaptability gives us the tremendous advantage of of immense versatility, which far exceeds the penalty of our very long development period. Continuous practise may even help prevent the onset of dementia such as Alzheimers, not by fortifying the connections so much as creating redundant ones as backups. As some connections fail, even the ageing brain is able to repurpose old ones to do different jobs. The degradation can't be stopped but its effects can be reduced.

* I wonder, though, how much research has been done on animal brains in this regard. After all, animal intelligence has continuously exceeded our expectations.

Decision time 

Plasticity also plays a role when the brain has to make a choice. The brain acts, says Eagleman, as a series of competing networks each vying for supremacy, although I rather prefer his other analogy of a parliament. The idea that we have many voices inside of us is quite real, with different networks continuously firing until, finally, the brain acts to "crush ambiguity into choices" and makes a decision.

Exactly how this happens is still somewhat unclear. There's a reward system, in that the brain favours networks which have previously made predictions that have been validated : if one mode of thinking has successfully predicted a good outcome in the past, that network will be favoured. Conversely, those networks which don't give predictions in agreement with reality are downvoted. The brain, then, acts as a sort of prediction engine, continually checking its findings against different models*. Even abstract concepts can act as a reward or punishment, but immediate, tangible effects tend to override all these. Hence it's easy to avoid doing the things we should do in favour of something else (eating ice cream instead of studying). 

* This makes it all the more mysterious that the brain is generally able to do this very well for low-level activities (few people continuously stab themselves with forks) but is often shite at higher reasoning (like believing in the Jewish Space Laser).

Eagleman's suggested self-help solution is to be like Odysseus and nail ourselves to the mast : ahead of time, ensure that the actual situation we'll find ourselves in is more tangibly rewarding/punishing than it otherwise would be. Don't give the brain the option to be distracted by temptation. Perhaps more interestingly, watching our neural responses (when we've got the option to do so) has also proven helpful in getting participants to learn self-control. Maybe one day we'll have phone-accessible EEG-hats and can cultivate our own desired responses using an app...

But exactly how the brain decides, "this network is the winner" and decides that this is the right approach is nowhere made clear. Emotions, says Eagleman, act as a heuristic for decision-making, combining all the possible effects into a simple sensation we can respond to, which explains that uncomfortable sensation while we haven't committed to anything. This, though, is still more description than anything explanatory, albeit a useful one. 

Finally, it's also interesting to me that neural activity is more coherent and correlated while we're asleep than when we're awake. Is the brain better able to get on with things without that pesky conscious mind sticking its nose in ? Maybe.

The nature of reality

This will have to be either very brief or extraordinarily long, so I'm going for the former. The world we experience is not the outside world itself, says Eagleman. Not only is there a delay in processing different sensory signals, but there's even a different delay for each type of perception. Yet somehow, the brain combines all of this into a unified experiential whole. 

And this unified approach appears to be crucial : to assign meaning to a sensory input, it must correlate to something else. If you only have visual data, you won't be able to see. While I had the impression from some of the case studies of Oliver Sacks that we learn to read the world around us, it's more subtle than that – interactivity is crucial, an idea developed further by Peter Godfrey-Smith (another one who's books I really must blog up sometime). Interestingly, when this multisensory approach is denied, the result is hallucinations... eerily similar to LLMs.

Perhaps one of the most compassionate parts of the book describes Schizophrenia as a sort of waking dream. In this condition, says Eagleman, suffers experience hallucinations without any kind of distinction between them and real, external sensory inputs. This naturally explains their behaviour, which may be perfectly rational but in response to a reality all of their own. I wonder if it doesn't go even further than that : in my dreams I rarely respond rationally to anything, yet at the time it feels coherent and logical. Maybe the logical reasoning centres are also impaired, without affecting the sensation that things have been done correctly... the reward networks might be all messed up.

More philosophically, Eagleman stresses that our perceptual reality is not reality itself : "the real world is not full of rich sensory events; instead our brains light up the world with their own sensuality". Perceptual time is also not experiential time (let alone real time). Experiments have shown that while high-stress situations make us feel like time has slowed, they don't affect our ability to think or perceive more quickly. 

Here I think I'd need to clarify with Eagleman himself exactly what he's getting at. I agree, our perceptions don't correspond directly to reality, in that our sensory experience has no special claim on validity (compared to, say, a bat or a whale), and that we have to learn how to create our own mental worlds*. But all the same, surely our experiences do have some equivalence with external reality. There is something outside that induces an experience; redness is not totally meaningless, nor is pain or sound or heat. We can verify these sufficiently well so as to reliably identify exceptions (like the responses of Schizophrenics) as being disconnected from that external reality. So in that sense, I don't agree that our perceptions are purely fabrications; since we have access to nothing else, it doesn't feel at all useful to me to claim that perception is not reality. Perceptual reality is the only thing we will ever have any access to.

* Eagleman mentions an interesting case of synesthesia in which letters are associated with colours. I wonder how this works, given that the letter symbols themselves have no meaning until they're learned.

Finally, I also don't agree that we don't have free will. Eagleman says (as do many others) that consciousness does appear to have some uses, particularly when learning a task for the first time or when things need to be done in an especially careful, controlled way, or when big-picture thinking is required – integrating one line of thinking from one subject with something seemingly unrelated. Seems fine to me, though as to why conscious experience should be needed for this is anyone's guess. And as for those experiments where brain activity can be predicted ahead of the conscious sensation of having made a choice... nah, I've covered that umpteen times already. Far more likely, in my view, that conscious sensation actually does involve being in control rather than a weird way in which the brain constructs a narrative* of deliberation for no good reason.

* Though I do also agree that constructing a narrative is something the brain does a great deal of, as well as creating a theory of mind for us to predict and respond to other people. Interactivity plays an interesting part here, too : while those with too much Botox are hard to read, they themselves have difficulty reading others as they're not able to be so expressive.

You will all become one with the Borg

Well, maybe. The brain's adaptability is not unlimited but it's tremendously powerful all the same; Eagleman gives the case of a girl with literally half a brain who lived a perfectly normal life (and see that recent post about the notorious but misreported Phineas Gage). A key concept Eagleman develops here is the "plug and play" model of sensory inputs. Essentially, our sensory peripherals – eyes, ears etc. – can be replaced and the brain will still find a way to deal with the information. It takes a while for the brain to learn how to process it, but it works (Kevin Warwick came to much the same conclusion in "I, Cyborg").

Personally I think this is most interesting stuff in Eagleman's repertoire. I love the idea of being able to, quite literally, reject your reality and substitute my own. And this actually works. Experiments have enabled people to "see" using tactile sensors on their backs, foreheads and tongues, hooked up to cameras. They can identify objects and accurately judge distances. It works equally well if the tactile interface is connected to an audio sensor instead of a visual one. And this can be done wirelessly, letting volunteers experience sensory input from other places on the planet – and in reverse, to control mechanical arms remotely. 

Real, it turns out, really is just an electrochemical reaction in your brain. 

Of course, things are still limited. The possibility of digitally scanning the brain is a stupendous, unrealisable challenge. Transhumanist dreams of fully uploading our consciousness are also likely futile even in a materialistic perspective, even if we did manage to scan our entire brain and its neural patterns. If consciousness is indeed just those patterns, then we could simulate the brain inside a computer, yes... but, Eagleman says, while it might well be something (or someone) that experiences something, it still wouldn't be us. Even from his perspective of consciousness being emergent, which I don't really agree with*, a transfer just doesn't work. A copy ? Sure, if it's really the patterns that are conscious, and not something to do with the physical substance. Even then, it would have to be capable of change, of forming new memories and responding to new sensations.

* He attempts to refute the argument of Leibniz's Mill, saying that yes, you can't find perception in any single mechanical part of the brain, but maybe you could in the emergent whole. I just don't see it. To me, the gap between experience and physicality is just too large, too fundamental to ever be bridged. The only way I can see this working is if mind and matter are, somehow, of essentially the same stuff (neutral monism, idealism, etc. etc. etc., you know the drill by now). Otherwise, I have no clue how a gigantic abacus could ever be conscious, or how this would happen if we moved the balls around but only in a very particular way.

In short, a fascinating and worthwhile read. I'm going to have to try and get hold of his TV documentaries and read his other books (of which I'm glad to see there are several) at some point. One day I should try a fuller write-up against materialism, but what's really interesting is that often the disagreement with my own, somewhat more dualist perspective, is that the disagreement isn't really that stark after all.

Whose cloud is it anyway ?

I really don't understand the most militant climate activists who are also opposed to geoengineering. Or rather, I think I understand them (or some of them at any rate), but I don't understand what their goal is supposed to be.

To a certain extent of course it makes good sense. The basic thinking that we've messed things up, so the best thing we could do is to step back, isn't unsound. It's completely natural to assume that because we got things so very badly wrong before, any further, deliberate intervention has a serious risk of making things very much worse. It could even be hubris to assume we're capable of getting things right, such is the complexity of the system we're dealing with.

I'm not unsympathetic to this view by any means. Anyone who is not merely advocating but actively gung-ho about the prospect of trying to alter the climate is someone to steer clear of. What I don't get is not the skepticism, but the denialism. And many of the reasons claimed for opposing geoengineering in principle (rather than objections to the specifics, which are often legitimate) are, so far as I can tell, a terribly toxic mixture of naivety and cynicism.

The most common retort is that geoengineering will distract from the more important business of cutting emissions. This, I think, is wrong-headed for a multitude of reasons. First, geoengineering takes many forms, and I'd argue that deliberately rewilding, planting trees, encouraging sea grass and other growth, all fit the bill of actively changing nature to help reduce the CO2 content of the atmosphere. And these solutions clearly aren't opposed to environmentalism in any sense : quite the opposite, they are perfectly aligned with classical environmentalist movements.

Second, how exactly are we supposed to reduce the existing CO2 without inducing the removal of carbon ? We have, so the claim is, already done horrible damage, but apparently we should now just back off and leave well enough alone. This is like going into someone's house, breaking all their furniture, starting a small fire in their dustbin but then slowly tip-toeing away claiming you don't want to make things worse. It doesn't make a lot of sense to me; if you make a mess, you have a responsibility to clean things up (or at least to try). I find it extraordinarily strange to claim that we've done such awful damage but shouldn't try and repair it.

And thirdly, our efforts to reduce emissions have been pretty pathetic so far. Yes yes, you can whine about overthrowing capitalism or some other damn fool idea as much as you want, but it isn't helping : it's schoolyard politics. The point is that geoengineering solutions appear to have little or nothing to do with this, and it doesn't look at all likely that if we took all the money away from geoengineering research we'd really invest it in other energy solutions instead. That idea seems crazy-naïve to me.

Which is why I don't understand what the goal of the opponents is supposed to be. Live in a shitty, overheated planet and make the best of it ? Sit back and watch everyone and everything suffer horribly ? That prospect is surely crazy-cynical, the product of people who've had the hope beaten out of them. It's daft.

No, the right solution seems clear : diversification. More than any other this feels like a situation where the idea of a single magic bullet is never going to work. Instead, we need to try and cut back our energy requirements wherever possible, change our energy production methods, change our farming techniques, change our construction strategies, work to a controlled decline in the population (otherwise Nature will do this for us, except it won't be controlled), and, yes, actively solicit the removal of atmospheric carbon. The idea that we can just, somehow, stop emissions tomorrow and that alone constitutes an acceptable solution is frankly bizarre. We know that simply isn't going to happen and it wouldn't be enough anyway. Pretending we should be singularly focused on this outlandish objective, at the exclusion of all others, is hindering the cause, not helping it. It's an outrageously unrealistic goal which distracts from what we really need to do, which is everything.

Which is not to say that some geoengineering "solutions" aren't a hell of a lot more scary than others. For example, injecting sulphur dioxide into the atmosphere to obscure the sunlight just slightly. The NYT piece linked doesn't have much in the way of data but some choice quotes :

“There certainly are risks, and there certainly are uncertainties,” he said. “But there’s really a lot of evidence that the risks are quantitatively small compared to the benefits, and the uncertainties just aren’t that big.” The only thing more dangerous than his solution, he suggested, may be not using it at all.

Once solar geoengineering began to cool the planet, stopping the effort abruptly could result in a sudden rise in temperatures, a phenomenon known as “termination shock.” The planet could experience “potentially massive temperature rise in an unprepared world over a matter of five to 10 years, hitting the Earth’s climate with something that it probably hasn’t seen since the dinosaur-killing impactor,” Dr. Pierrehumbert said.

On top of all this, there are fears about rogue actors using solar geoengineering and concerns that the technology could be weaponized. Not to mention the fact that sulfur dioxide can harm human health.

Dr. Keith is adamant that those fears are overblown. And while there would be some additional air pollution, he claims the risk is negligible compared to the benefits.

To be clear, I'd probably put this way down my list of preferred geoengineering solutions. Injecting chemicals known to be harmful is, pretty obviously, not exactly the ideal solution. But all the same I take great issue with :

Raymond Pierrehumbert, an atmospheric physicist at the University of Oxford, said he considered solar geoengineering a grave threat to human civilization. “It’s not only a bad idea in terms of something that would never be safe to deploy,” he said. “But even doing research on it is not just a waste of money, but actively dangerous.”

Now this is extremely foolish. Consider the trajectory of the climate. Now consider what happens if (or rather when) we fail to reduce emissions and things get bad. What exactly do you think people will do then ? It seems to me that when pushed, there is every chance that desperate people will look for desperate solutions. Only, if we don't do the research now, future generations may implement it regardless, heedless of the unknown consequences because that is exactly what desperate people do. Better by far to research this now while we have time. Do as many simulations as possible, run controlled tests where possible, monitoring how the chemistry changes in laboratory-reproductions of the upper atmosphere and eventually in small-scale open tests. Likewise :

Then a professor at Harvard, Dr. Keith wanted to release a few pounds of mineral dust at an altitude of roughly 20 kilometres and track how the dust behaved as it floated across the sky. A test was planned in 2018, possibly over Arizona, but Dr. Keith couldn’t find a partner to launch a high-altitude balloon. When details of that plan became public, a group of Indigenous people objected and issued a manifesto against geoengineering.

Three years later, Harvard hired the Swedish space corporation to launch a balloon that would carry the equipment for the test. But before it took place, local groups once again rose up in protest. Within months, the experiment was called off.

“A lesson I’ve learned from this is that if we do this again, we won’t be open in the same way,” Dr. Keith said.

That last is pretty sinister. Either we can approach this rationally and sensibly and have controlled, transparent research, or we can respond with knee-jerk, absurd levels of ideological purism and reap the whirlwind. We are going to need geoengineering research : in this technique, in all techniques, because we need as many solutions to the climate crisis as we can. Nothing less is adequate.

(Note : I say research. Not necessarily this particular solution, which I'm instinctively against. But not investigating it at all, not even considering the possibility without any actual data to back up the objections, that's mad. Even more so for other solutions which can be much more limited and controlled in their affected area, e.g. algal blooms in reservoirs.)

A second, more academic article explores the prospect of marine cloud brightening. Instead of making the sky darker, it proposes injecting small amounts of salt into clouds to make them more reflective. This would still not be among my top priorities for geoengineering (I think those would probably be rewilding and direct carbon capture) but salt is at least a lot better than sulphur dioxide. That article is also much more measured, setting out a detailed program for how practical tests could proceed and when they should stop. It also makes it clear that it would not be, by any stretch, any sort of "quick fix", with the results possibly not known for decades. Which is exactly why we should start as soon as possible. It might also help us better understand how particulate matter in the atmosphere behaves more generally, something we're been doing anyway... better, surely, to study things in more controlled conditions than making observational inferences where there are numerous confounding variables.

Well that's really all I wanted to say on the matter. It's right to be cautious about geoengineering schemes, but it's silly to treat them as all being equal, and foolish in the extreme to restrict research on any of them. We need to do this now while we can still can. Otherwise we may find ourselves in a situation where we don't have the luxury of investigation at all.

Review : Oppenheimer

Let's start the new year with something positive : nuclear bombs.

Okay, let's not do that exactly, but after having slated pretty much all of Christopher Nolan's recent cinematic offerings, I feel honour-bound to give the guy his due when it comes to Oppenheimer. After being quite irritated by being unable to see it at the cinema (we waited so long for IMAX bookings to subside that by the time we decided to go for a regular screening, they were then only showing it at unfeasible hours), I finally saw it at home on 4k. And, having been disappointed time and again by Nolan of late, I'm glad to say that this is a long overdue return to form.

To recap, I loathed Interstellar with its rampant inaccuracies but claims to the contrary and its daft idea of "love crossing the dimensions" (urrraaarrrrggkkkk !). I found Dunkirk to be hugely underdone and anti-climatic. And Tenet felt like intellectual masturbation, relying far too heavily on a pretentious gimmick and being all but inaudible. While I admire Nolan's commitment to practical effects, sometimes he goes too far with this. Narratively too, many a time I've wondered if he's so pretentious that he's likely to disappear up his own arsehole in a singularity to rival anything in Interstellar.

But when he's right, he's right, and after such a run of largely crap, Oppenheimer at long last delivers the goods. It starts a little worryingly with Oppenheimer portrayed as the classic lone maverick genius, with one truly laughable line, "I liked your paper on molecules" repeated several times despite sounding like he's just come out of pre-school. And we get a lot of genuinely very pretty minimalistic art sequences to portray Oppenheimer's ability to see beyond the mundane surface reality and into the quantum realm, which is, I stress, gorgeous, but real scientists aren't usually so up themselves.

Shut up, we're not.

The style of delivery also takes some getting used to. It frequently jumps back and forth between different time periods and for a very dialogue-heavy movie it's extremely fast-paced, and add to that that most of the dialogue feels like the characters are literally reading out of a biography.

All this has the potential for disaster but... it works. The non-linearity adds a genuine extra tension to the narrative without being distracting, because it compares events which are similar enough to be directly relevant to each other. As a historian might draw parallels between different events through a direct analysis, so the movie presents them here. It also doubles as a story arc, beginning with a fairly standard narrative but gradually and seamlessly transforming into an Oppenheimer-vs-Strauss courtroom drama that eventually dominates and concludes. I think perhaps a few parts would be better left out and replaced with some more cinematic, music-dominated visuals instead, just to slow things down a bit, but this is a very minor quibble.

And what begins as another, "oh no, it's the Imitation Game* all over again" feeling rapidly transmutes into a pleasant realisation that "oh, you're not doing that at all". Oppenheimer is depicted as having a world-class understanding of the physics, yes. But he's not at all shown as being a lone genius or a revolutionary, but rather as an administrator. Many other figures** are from his own lips given to be more important than him, or at the very least necessarily complementary (in fact we don't really see any particular breakthroughs Oppenheimer himself makes regarding nuclear physics, which is largely left to others). He isn't especially socially awkward and there's plenty of mentions of his political leanings and activism. Overall, what emerges is a vastly more real, more complex depiction of a flawed and fraught human being than anything Benedict Cumberbatch would ever be likely to portray. For this alone I give the movie huge kudos.

* A perfectly good movie which I enjoyed very much, but it does fall for the standard lone-socially-awkward genius myth very heavily, and I really wish movies would stop doing this.

** Noland says in the extras that this is a conscious choice not to use composite characters and I applaud him for that. The large cast is never distracting, with each individual appearing when they're needed and not one moment longer. You never find yourself wondering what happened to so-and-so or who the hell that guy is. Everyone is there for a purpose and there are absolutely no pointless backstories. What we get is a far more realistic portray of the collaborative scientific process that most movies try to depict, without sacrificing narrative clarity.

I feel that by choice the movie has breadth instead of depth. It covers all the major moral issues regarding nuclear weapons and the impact on the scientists who built them, but at the expense of examining any of them in any detail. I think this is probably for the best. The overall feel is that it presents all of this to the audience for discussion, raising all the major points that need to be raised but not ramming any particular message down anyone's throats. Even the most villainous characters aren't treated as pantomime psychopaths but with some sympathy, making them all feel very much more nuanced and believable. Whether they were right to build the weapons in the first case, let alone use them, let alone use them against civilians... that's quite rightly left to the viewer to pronounce judgement, all the while showing that the same doubts gnawed at the protagonists as they surely must have done. It gets, I think, properly into the mindset of the times, of those caught up (in their own ways) in a vast and bloody conflict where there simply were no good choices to be made. It doesn't use the benefit of hindsight to cast judgement on anyone.

And it sets this in the broader political context of McCarthysim as well. In fact I think this may be my favourite, most subtle aspect of the film, examining the various political forces at work, the different structures of the political, military and scientific organisations at work on the Manhattan Project and beyond. I like especially that the detonation of the bomb is not the climax of the film but we get an extended epilogue of what happened afterwards which is probably for me the best and main point of the movie. In essence, it uses nuclear weapons as a clever plot device whilst simultaneously keeping the development process itself interesting and engaging entirely on its own terms. You could, if you so chose, stop watching after Trinity and you'd have had a damn good movie.

I do think perhaps this is a case of a movie that thinks too much and feels too little, but not to any serious extent. Quite unlike Tenet, it never gets hung up on its own clever nonlinearity. By and large we get a very thoughtful insight into the emotional lives of the characters; it demands concentration of the audience to follow everything that happens, but it isn't equivalent to solving a Sudoku puzzle in order to understand the basics, which is an approach to filmmaking I despise.

Overall, extremely solid stuff. The explosion is spectacular, the cast are perfect, the soundtrack is great (love Hans Zimmer but thank you Nolan for finally giving someone else a chance !), cinematography is perfect. I'm gonna give this one 8/10. It's a brilliant film, occasionally just a little too clever for its own good, extremely well-balanced but perhaps lacking in depth from time to time; I would rather have had a little less detail and more moral philosophy discussions. But this is probably only personal preference and I could probably be persuaded to bump this up to 9/10, and I think for the second half/final third of the film I certainly would.

Nolan, all is not forgiven. You still need someone to give you a good hard slap on the mouth from time to time. Nonetheless, welcome back to the land of sanity, and enjoy your well-earned accolades.

Review : The Mind's Eye

Having been thoroughly impressed with both An Anthropologist On Mars and The Man Who Mistook His Wife For A Hat, I felt pretty confident that any other Oliver Sacks book would surely be well worth reading. So I picked up The Mind's Eye at my favourite local bookshop-bar some time ago, being determined to at last actually buy a book there and not just drunkenly peruse them as is my usual wont. And then it languished on my shelf for some time, I already being deep in my Tolkien binge at that point.

I'm afraid I have to say my ill-treatment of this (ultimately very satisfying) book continued. When I finally started it, I found it a slower burn than the others. The first few cases described are undeniably interesting but add nothing new to those covered previously. The way that we almost literally 'read' the world, assigning meaning to form and colour, is fascinating stuff, but simply repeating this without trying to understand it more deeply can quickly wear thin.

It didn't help that, now being on holiday, I naturally went on a book-buying spree. Prague has pretty good English bookshops but of course the selection back home is always better. So I did that rarest of things... I paused and... started another book. That's normally a death knell for anything I'm reading, the direct literary equivalent of eloping with a cheerleader.

(The analogy holds quite well, since my interest was diverted by a big, full colour, fully illustrated book on castles of the Welsh princes. Which is lovely, and you can read my review of that one here, but it certainly isn't worth blogging about.

I have no idea if this analogy makes sense to anyone else, but dammit it seems appropriate to me.)

After getting this shameful infidelity out of my system, I decided to resume TME. Fortunately from the point where I'd stopped it rapidly became more interesting. The theme is how mental imagery works, which for philosophy of mind is the equivalent of crack cocaine. And so once again, Oliver Sacks delivers. I'd give it a 7/10 overall; the early parts are not as interesting as some of his other stuff (at least if you've read his other works), but the later bits are if anything even more so. 

Face blindness

One of the first interesting cases is one of the simplest, prosopagnosia  : the poor ability to recognise faces. Of course everyone forgets faces from time to time, but this is well beyond the norm. In some extreme cases this can extend to one's nearest and dearest (or even one's own reflection !), but far more common is to simply have severe difficulties with more casual acquaintances. Sacks describes his own personal experience with this, and those of other academics. One went so far as to have a notice on his office door explaining that everyone should introduce themselves. 

Exactly how this happens is not well understood, perhaps because being bad at faces is so normal as to be barely recognisable as a disorder (Sacks compares it with dyslexia, which is about equally common but far more widely recognised), and can typically be circumvented. What I found interesting were cases where context helped a great deal, that if a "sufferer" saw person X at location Y, then they'd recognise them straight away, but have difficulties if they were in location Z. And that's very familiar; I've been caught out many times by seeing familiar faces in unfamiliar locations (who hasn't ?). Several times I've walked to or from work and the server at the local restaurant has waved at me, and only later have I realised who on Earth it was. Familiarity, Sacks notes, is not recognition.

It makes sense that the brain would have some dedicated functionality to recognising something as common and of such vital social importance as faces*. It also makes sense that something this specific could malfunction, or work sub-optimally. But the location-based aspect** reminded me of albatrosses, who completely fail to recognise their own chick if it falls even just outside the nest. This seems absurd, but clearly, prosopagnosia indicates that the human brain is not nearly so different from our feathered friends as we might presume. Our perception of reality is weird.

* And it partly explains my racist grandmother, because face recognition is learned early on. Reversing the typical western perspective : "One prosopagnosic colleague acquaintance, born and raised on China, went to Oxford as a student, and has lived for decades in the US. Nonetheless, he tells me, 'European faces are the most difficult - they all look the same to me.'"
**There seems to be also a correlation with having a bad memory for places.

Stereoscopy

The second interesting case is one of those exceedingly rare parts of Sacks which is wholly positive : the case of a woman regaining stereoscopic vision after losing it in infancy. In a previous book he describes how an operation ostensibly restored full sight to someone who had similarly lost vision completely at a very early age, but in that case, the results were almost tragic. The patient could only learn to see again with great difficulty, at first lost in a frustrating mass of meaningless colour and form. Just like learning to read, the information was there, but the meaning was not.

For the stereoscopic patient things were very different. Despite the prevailing medical belief that stereoscopic vision must be acquired before the age of two, the now middle-aged patient was essentially bestowed with fully normal depth perception. And this was nothing but beneficial, an endless delight to the patient to finally "see the space" between objects.

This particular patient was also a professor of neurobiology. In a direct analogy to Mary's Room, she'd told Sacks years before that she thought she had enough knowledge to imagine what stereoscopy must be like - but after the operation, she recanted, saying it was a wholly different experience. Stereoscopy turns out to be a qualia, something which cannot be adequately described but only experienced. Somehow this had never really occurred to me before.

The consequences of living without it also took me by surprise. True, this is just one aspect of depth perception, with a host of other factors also at work. But some, including Sacks himself, rely on this more than others (it seems stereo depth is experienced to different degrees, with some people reporting far more pronounced depth when viewing stereo images - pairs and stereograms and the like - than others). Without it the world feels like watching a movie or a painting, a continuous series of bizarre, Escher-like illusions with perspective being almost irrelevant.

I'm surprised that the differing focus of nearby and distant objects didn't destroy this effect, but it seems it didn't. Clearly this long-term effect is something qualitatively different from what one experiences if one merely closes an eye.

Hallucinations

Next, Sacks returns to his more usual bittersweet tone as he describes the early stages of his own eye cancer. I hesitated to read this. I deeply appreciate Sack's sympathy for and empathy with his patients, but my main interest is the philosophical implications, the distinctions and overlaps between mind and body. Reading for the sake purely of an emotional journey is really, for many reasons, just not my thing at all. To be blunt, I can't handle it and I don't want to.

But it's not like that. Somehow, Sacks maintains his usual style even here, and if it's necessarily more emotive than usual, the intellectual curiosity hardly plays second fiddle to this. Not for nothing is he called the poet laurate of neuroscience.

Sacks describes how his cancer caused a series of changes in his vision. With an operation to his retina, at first things seem to have been as one might naively expect : a central patch of darkness in his right eye. But as things progressed (sometimes improving, sometimes degenerating), the effects became much stranger. It began with simple hallucinations of abstract shapes, but rapidly turned to persistence of vision : "If I have been looking at something and then close my eyes, I continue to see it so clearly that I wonder whether I have actually closed my eyes."

This effect became astonishingly pronounced, but before that there were weird effects on colour. Colour vision was all but lost in the centre of his field of view in the damaged eye, with colours from the remaining peripheral vision suffusing into the centre - and of course varying hugely depending on whether he used his good left eye, right eye, or both. Having different colours available with each eye is strange enough, but it became weirder still. The blind spot would "fill in" based on the surrounding colours in "about a second or two" :

The next day I tested this with a blue sky and found the same result. The scotoma became as blue as the sky... when a flock of birds flew by, they suddenly disappeared into my scotoma, emerging on the other side a few seconds later - as if they had been cloaked in invisibility like a Klingon warship.

Colour was only the beginning. Like modern image-generative AI, the blind spot could fill in with patterns : brickwork, clouds, wallpaper... though not faces or other highly complex shapes. 

I started to think of my visual cortex not just as a rigid duplicating device, but as an averaging device, capable of sampling what was presented to it and making a statistically plausible (if not photographically accurate) representation of it.

After gazing at the bookshelves in my bedroom for a few minutes, I closed both eyes and saw, for ten or fifteen seconds, the hundreds of books arrayed in almost perceptual detail... I had the sense that my visual cortex was now in a heightened or sensitised state, released to some extent from purely perceptual constraints... These images or hallucinations have greater clarity, are more fine-grained, than perception itself, as if my inner eye had an acuity of 20/5 rather than 20/20.

I can at least dimly conceive of what this must be like. I too (Sacks was a big fan of stereoscopic imagery) appreciate stereoscopic vision experiences, mainly through VR these days, but I've got a couple of books of stereograms back home*. Viewing them, the sense of depth becomes somehow more pronounced, more "real" than in regular vision, in way that's not at all easy to articulate. Similarly, in very deep lucid dreaming, I get an experience of generating the imagery, a sense that things are somehow impossibly detailed.

* Though more recently I also have Brian May's Mission Moon 3D, which is not well written but does have wonderful stereo pairs.

Of course in Sacks case all this comes at an enormous costs. Besides the obvious, one of the stranger elements is that seeing can be quite literally believing. Eventually losing his peripheral vision in his right eye completely, Sacks describes how this is markedly different from having an eye patch : not only is the perception itself gone, but the whole concept of vision and the visual field is lost. He describes this also in patients who became fully blind and eventually lost mental imagery, or even the memory of visual experiences, absolutely. In his own case it was more limited but still severe : if something moved into missing field of view, for him it was almost as if it didn't exist. 

Then a voice to my right - her voice - said, "What are we waiting for ?". I was dumfounded - not just that I had failed to see her to my right, but that I had even failed to imagine her being there, because "there" did not exist for me. "Out of sight, out of mind" is literally true in such a situation... I am still in a world of suddenness and discontinuity, of sudden apparitions and disappearances.

Visual thinking

There is one interesting aspect to some of the earlier cases mentioned in the books. It's possible to forget how to read but not how to write. For some people this improves by doing the physical act of tracing the letters in the air. Another learned to trace the shapes of letters with his tongue, replacing reading with a sort of tongue-based writing.

The final section of the book returns to the more general case of this, considering how vision is integrated with thought. Sacks elaborates on the case of losing the whole concept of vision, describing how in one case this was seen as a "dark paradoxical gift", since the remaining senses were so much more heightened, in their own words to the extent of being, "a whole new order, a new mode of human being". But while it can and does happen - the idea of sensory compensation is practically a stereotype - it is not necessarily typical of actual experiences. It's also possible to go in exactly the opposite direction, not to lose mental imagery, but ironically to massively enhance it.

If Sacks hints at this with his own hallucinations, with the visual cortex having nothing else to do but make stuff up, in others this can be ruthlessly controlled. His own (sighted) mother could look at a lizard skeleton and mentally rotate it, accurately drawing it from different angles from her mind alone. But one blind psychologist used descriptions and his other senses to develop his inner eye to such a degree that it served as a full replacement for his eyes - accurately enough to replace the guttering on his roof !

"... to imagine, to visualise, for example, the inside of a differential gearbox in action as if from inside its casing. I was able to watch the cogs bite, lock and revolve, distributing the spin as required. I began to play around with this internal view in connection with mechanical and technical problems, visualising how subcomponents elate in the atom, or in the living cell."

Others experience imagery in more artistic ways, or as if shown on a screen, but all of the "visual blind" seem to have a far, far more intense and vivid experience of the inner eye than most of us do. There's also a connection to proprioception, with arms and legs being directly visualised as they move them. And this can apply to other senses as well, with a deaf lip-reader describing the experience as hearing, not seeing. Much like in this famous gif, I suppose.

Sacks also touches on aphantasia, the lack of mental imagery. Our visual imaginative capacity varies considerably between individuals, but I still find it extremely hard to grasp the concept of those who don't have it at all - especially for those with highly visual professions, like surgery and even artists (is a highly developed inner ear perhaps how Beethoven managed ?). Sacks, and some of the aphantasic themselves, suggest that they must be forming mental images somewhere, they're just not consciously accessible.

But are mental images really a sort of imagery ? It appears so. Studies suggest that summoning mental images takes effort and time and uses the same area of the brain as for visual perception. The final section of the book is very similar to Livewired, which to my shame I still haven't blogged yet*. Sacks notes that, as earlier, the brain is remarkably able to adapt, re-purposing the visual cortex in the blind to handle mental imagery more precisely, freed from the need to also process incoming signals from the eyes. This may be why it hallucinates when deprived of signals in the sighted as well as explaining how the blind can develop this to such a remarkable degree.

*Stuff keeps coming up. And unfortunately the book is so good it's hard to plan out a post that wouldn't just be reprinting the whole thing and get me sued for copyright.

In similar passages to parts of Sentient, Sacks describes sensory substitution, e.g. the blind using a cane to see the world around them, transforming touch and sound into a true mental picture (Sacks puts speech marks around some of these terms but I've decided it may be worth taking this literally). Again overlapping with Livewired, he describes tactile inputs sent to the tongue from otherwise ordinary cameras, allowing a crude but effective tongue-based vision. And it really does seem to manifest itself in the brain as vision, not just as a weird sort of touch.

Finally, at the very end he wonders if the congenitally blind could also be described to have true mental imagery. Here I think I have to disagree. He suggests that language is somehow able to overcome their sensory deficiencies and enable them to truly see with the inner eyes, albeit not understanding how this works. I think a simpler explanation would be that perhaps the brain isn't entirely live-wired; it doesn't figure everything out from pure experience, but comes with some initial draft of how to handle the basics of vision : shape, colour, distance, etc., leaving only the higher meaning as that which has to be learned. But who knows ?

I've long poo-poohed the idea that reality is "nothing like" our perception of it, all the while disparaging the foolish idea of materialism. Sacks' works make it abundantly clear that our perception is far stranger than we usually realise. 

The way I think I reconcile my opposing viewpoints - and I'm quite uncertain of my own opinion here - is as follows. Perception is that which our minds construct from our senses. Our sensory apparatus directly interacts with the world, but perception is a mental act. The brain is quite capable of making up stuff all by itself, but it's also capable of constructing it directly from sensory data, albeit into wholly arbitrary forms. Most of the time those worlds are separate, and usually the rendered internal worlds are self-consistent, but the brain is more than capable of making outright mistakes and constructing impossibilities. Hence the result is what it is : a glorious but mostly functional mess.

Review : Planta Sapiens

After a string of marvellous books on animal sentience, unfortunately it's time for a bad one.

If you do a search for "plants" on this blog, you'll find my position on whether plants can be said to be intelligent or self-aware* has long been on the skeptical side of uncertain. In particular, there have been experiments claiming that plants can learn and remember, that they can make choices, and in particular that they can show Pavlovian responses. That one in particular strikes me as potentially a good route to convincing me that they have inner, conscious lives. Which makes it disappointing that the experiments have problems with reproducibility, despite some criticism being unduly harsh (you might also recall the findings hinting at fungi also being capable of making intelligent, sentient choices).

* I plan to try and define these terms a bit better in a future post, but for now I'll use them very loosely.

Likewise, I think that panpsychism is a philosophically valid, intelligent position but I just don't like it very much. The idea that everything has a consciousness, however rudimentary, just seems extremely strange and largely pointless to me. I lean considerably more favourably towards the idea of "biopsychism", in which all biological life has a consciousness, but even that I don't find especially brilliant.

Still, if you can convince me that plants are conscious, I'll be very much happier about biopsychism and would give serious reconsideration to panpsychism. As I said, some of the experiments are very intriguing, so I'm definitely persuadable on this issue.

All told, I'm the prime audience for Paco Calvo's Planta Sapiens. This purports to be a scientific account of plant intelligence written by a philosopher-turned-botanist. His aim is to convince the reader that plants do indeed have minds, but I have to say that while not without some interesting points, as it stands the book is a disappointing failure that's frequently an actively irritating experience to read.

Unlike other recent reads I can keep this to one post. Of the few genuinely interesting findings that Calvo does highlight, I'm going to have check the references and give them their own post in due course. For now, I confine myself to the book.

The review bit (skip this for stuff about plants)

Calvo begins quite properly with an exhortation to keep an open mind. And he keeps going with this. And going, and going, and going, right through the entire book. All too often I could not but help thinking, "shut up and tell me about the plants !". Strangely, he also likes to detail the exact progress of his career, making odd and irrelevant references to his own and his colleagues employers and research institutes. At times the anecdotes did help me warm to the guy despite the lack of substantive content, but by the end the final chapter was just a pointless, outright stupid rant and I wanted to tell him to get over himself.

Yeah, it's not great. It's a short book, but Calvo chooses to use most of the space for talking about non-plant related things. These include his career, the need to keep an open mind, other people's careers, socialising at conferences, the need to keep an open mind, philosophy of mind, unrelated analogies, the need to keep an open mind, and the harsh responses from mainstream botanists. Oh, and of course, the need to keep an open mind. Again.

Dude, I'm open-minded enough to be reading the damn book. You don't need to force the open-mindedness down my throat. Give me something to be open-minded about, for goodness' sake. It's bordering on insulting, to be honest. 

Worse, even when plants do make an appearance, their behaviours are rarely (but importantly not never) as interesting or as convincingly conscious as Calvo seems to think. Frustratingly, his anecdotes do at least demonstrate that he's aware of why people disagree or don't think the evidence is that convincing, but he fails to address their points. He spends a lot of time explaining why plants could be conscious, a position I'm already sold on, but my guess is that no more than 5-10% of the book actually contains anything about plant behaviour which is anywhere near interesting enough to warrant this.

Now to be fair, it's not that some of the extraneous content isn't valuable; some of it is genuine rubbish but probably about two-thirds could have some value. If this is your first encounter with the world of philosophy of mind, I suspect you could do worse : his descriptions of the problems and the histories behind them are lucid and readable, and taken on their own they're very light but perfectly decent. The problem is that without the experimental plant-related backup, all of this is just little more than wishful thinking, a thick layer of icing with precious little cake. It's a bit like having a car manual that tells you in tedious detail about what a magnificent car you own but forgets to describe how to switch on the lights.

In other words, yes, plants could be conscious. I agree. NOW BLOODY SHUT UP AND TELL ME THE EVIDENCE THAT THEY ACTUALLY ARE !

I'm giving this one 4/10. There are brief moments when something really interesting crops up, and most of the superfluous content isn't actually bad in itself*; I give further credit because Calvo does duly present concerns about experimental verification and doesn't take everything on face value. It's just that the book is too short, but not in a good way. It's like a cavalry charge without infantry support : most of the content would be perfectly good as reinforcement, but is useless on its own. It's also quite repetitive, and while I value some repetition to drive a point home, this much is excessive.

* Some is though. I don't need to know the backstory to every conference or what sort of wine you were drinking. A great deal of this feels like a blog post that hasn't translated well into a book format and just becomes outright annoying.

Even so, what blog-worthy stuff does the book contain ?

The content

1) Interesting plant behaviour

A hopeless beginning

Calvo begins unexpectedly with anaesthetics. Plants succumb to the same chemicals used to induce unconsciousness in humans. Calvo starts off gently here, highlighting that more important than this is the fact that plants do have some kind of active state that can be suppressed. And this is not at all an unreasonable claim which is worth bearing in mind

A running theme that Calvo develops early on is that plants may need intelligence precisely because they're fixed to one location. Animals, he says, have the luxury of being able to correct their mistakes. True, they have to have additional brainpower because of all the extra activities they do, but they can generally afford to try again if they mess up (think of how most animal hunts end in failure). For a plant, because its movement is largely growth-based, each failure is more costly. They can't self-correct so have a greater propensity for fatal mistakes. So they may, he argues, need to think.

But this isn't at all convincing by itself. It might be advantageous to the individual, but it's hard to see any species-wide requirement for thought : plants vastly outnumber animals and are in no danger of simply being gobbled up. Far more persuasive would be examples of plant behaviour that are too complex to explain by mere stimulus response.

Calvo believes very strongly in a softly-softly approach, so he begins with a common, simple behaviour : circumnutation. When reaching for a support, plants circle around in a lasso-like motion before finally gasping on. This can be surprisingly rapid, with a complete period of about two hours in some cases, with the final contact taking only a few minutes or perhaps less (because the rest of the motion is so slow, this is difficult to capture in time lapse).

But what's supposed to be intelligent about this I've no idea. A circular motion seems like a decent and simple enough way to cover a wide area in a search for structures. There doesn't seem to be anything about it which meets Calvos' own criteria for cognition, e.g. being adaptive, flexible, and goal-directed. Nor is there anything all that remarkable in plant's producing chemicals to influence animals. And while the ability of some plants to track the Sun on cloudy days (though not very accurately) and anticipate where it will come up the next morning is quite interesting, Calvo himself describes quite convincingly how this is due to purely physical, mechanistic processes rather than mental computation.

Slightly more intriguing are that plants sense a wide variety of external stimuli : water, light, touch, chemistry (airborne odours and soil chemistry), temperature, etc. They have to in some way compare all of these different strands of information and juggle them against their competing, individual needs. So at least some of the rudimentary requirements for consciousness are there, but it doesn't follow that they necessarily actually implement this. Everything could still perfectly well be pure stimulus response with different thresholds governing the result. Likewise, while plants undoubtedly communicate with each other through chemicals (either airborne or through direct physical contact), Calvo heavily implies that this means they must be intelligent, but why this should be so isn't at all obvious to me.

A few promising developments

We do eventually get some more intriguing behaviours. Calvo mentions the Pavlovian experiments I referenced earlier and, to his great credit, is careful to stress that these results haven't been replicated. But he's more bullish about describing other, extremely similar results. Apparently both pea plants and strawberries are capable of learning that particular light levels (either bright or dark) are associated with higher nutrient levels in the soil, putting down roots in greater amounts in the areas of light they're been trained to associate as beneficial*. 

* Quickly skimming a later review it seems that this study was fraught with problems, however.

This is deeply frustratingly brief : the final four pages at the end of chapter three are what the whole chapter should have been about. Give me details of the experiments. Give me the criticisms and counter-claims. Don't waste me time with an enormous prelude instead ! Credit where credit is due, he does give references, so expect more on this in the future.

Having prematurely "established" to his own satisfaction that plants are probably intelligent, thinking beings, Calvo proceeds to tackle how this might be. This bit feels somewhat better. Obviously plants don't have nervous systems, and I'm entirely sympathetic to the idea that you don't need this for consciousness. But they do use electrical currents, with various external stimuli (light, gravity, touch and all the rest) being able to trigger measurable electrical impulses. And while they don't have nerves, they do have internal networks along which such signals might propagate.

There are two (!) other points about plants which are interesting. Apparently some parasitic vines behave in an extremely similar way to hunters. They have a sense of smell and can follow a trail, in time lapse sweeping back and forth just like an animal. They will adjust their hunting strategy based on what sort of trail they're following, showing a clear preference for tomatoes over wheat. 

The second point is that plants have a more developed sense of light than we might suppose. In a few cases they actually prefer darkness, apparently in response to the need to search for support structures (e.g. trees) on the forest floor. Weirdly, they can also sense colour (or at least wavelength), having preferences for different coloured poles over others.

Finally, Calvo points out that bacteria have been shown to respond differently as a result of their actions as they interact with the world, as though they're observing and learning. There's even evidence for Pavlovian conditioning. And I'll grant that if mere bacteria can do this, then it would be weird if plants couldn't, but I'd prefer to check the references before commenting any further.

The two most interesting things here to me are the possibly Pavlovian responses and the wavelength sensing. The Pavlovian behaviour I find interesting because it suggests something much more indirect than pure sensory stimulation, especially when it happens as a result of a completely unrelated activity to what the plant is seeking. This, if true, is at the very least some sort of learning; it might be a step too far to call it "reasoning", but it would be a step in that direction. The wavelength/colour issue might imply qualia. For that, the best I can come up with is that we'd need some way to create an illusion that would trick the plant into perceiving a colour that wasn't really there, but how we'd do this I don't know.

That's all there is, in the entire book, about behaviour that seems genuinely cognitive and not just automatic. It feels like scraps from the table at most.

2) The other stuff

While much of it is just standard introductory philosophy of mind stuff, there are some interesting bits in the rest of the book I do want to mention.

The first is a nice joke about vitalism :

"If you presented a dynamo to scientists of various disciplines, they would all look at it in different ways. A chemist might dissolve it in acid; a molecular biologists would take it apart and describe its components in detail. But, were you to suggest that 'an invisible fluid, electricity' flowed in the dynamo, the flow of which ceased when it was dismantled, they might 'scold you as a vitalist'."

Which is a reasonable enough point. Likewise, that biologists are apparently only just getting to grips with the idea that fish are sentient is incredibly worrying and bordering on the idiotic. Calvo is right that the flip side of anthropomorphism, which indeed we should avoid, is anthropocentrism : the idea that humans are uniquely special and superior. Both ideas would seem inherently and almost self-evidently wrong-headed; my news feed frequently comes with headlines about how scientists have "discovered" what all pet owners have known for years. I don't mean some nuance about animal behaviour, I mean bloody obvious things that they ought to be ashamed of for not realising decades ago. So I'm with Calvo on that score, especially as this seems thoroughly backed up my other recent reads.

But alas, that's just about where my sympathies end. It does not follow that, just because some ideas considered crazy in the past have become accepted into the mainstream today, that all crazy ideas deserve serious treatment. There's quite a strong whiff of the classic "they said I was maaaad !" vibe about the whole thing.

For instance, in yet another effort to encourage open-mindedness, he quotes a philosopher who bizarrely believes we can escape from Mary's Room. His analogy was... we can get used to the differences between the Celsius and Fahrenheit temperature systems. 

Da fuq ?

Riiiight. So I'll just go and imagine some new colours then, because apparently that's totally the same thing. Good grief.

And then Calvo doesn't do himself any favours by singing a paean to Martian robots but then saying it would be better if they could just grow from place to place for some reason. Good lord man, what are you talking about ? He goes off on one about the rights of plants but fails to explain what, exactly, if plants have awareness, are we ever supposed to eat without feeling massive, crippling levels of guilt, which would seem like the most obvious question in the world.

And finally there's a horrible anecdote that is unbecoming of professional scientists; here my sympathy returns partially to Calvo. As with the last book, there seem to be some appalling biases in the life sciences. For god's sake people, sort yourselves out.

"After out meeting, a group of leading plant physiologists published a paper attacking our work, without even the veneer of politeness usual in academic publishing. They argued that 'dubious ideas about plant consciousness can harm this scientific discipline', and 'generate mistaken ideas about the plant sciences in young, aspiring plant biologists.' We were not only wrong, they seemed to think, we were dangerous : 'serial speculationists' looking to dismantle respectable science from within. They urged funding agencies to refuse us and journals to reject our papers, to keep our 'prolific speculating and fantasising' out of scientific discourse."

Now some of this is inevitable : if you really think a discipline has been corrupted by pseudoscience, it needs to be called out. But you don't do it in personal terms in a paper. Just as I wish Calvo would shut up and make his actual claims, so the counterarguments should be restricted to just that. If you want to make more personal attacks, do it by all means*, but not in a journal. 

* Sometimes crackpots deserve to be treated as such.

Yet there are two sides to every story. I don't know about his papers but Calvo's book is absolutely 100% the work of a serial speculationist because there's so little bloody data in it. He might very well just be a nutter; the Michio Kaku of botany, perhaps. A very quick look at the paper in question and I think some of their claims are pointless and silly ("plant's just can't be conscious, mmkay ?") but some are very likely correct (evidence for specific experiments being wrong, evidence that Pavlovian responses can occur - surprisingly - without consciousness). From what I've skimmed, it may well be that the entire edifice of research into plant intelligence is without any foundation at all.

But for that, it seems prudent to reserve judgement and read the actual papers. Pending that, I might well revise my assessment of the book. As it stands, Calvo certainly hasn't done himself any favours with this at all.

An Immense World (II)

This is the second part of my summary of the most interesting bits of An Immense World. In the first part we saw familiar senses being used in unfamiliar ways. In this concluding post, I'll look at the weirder, more exotic senses animals posses. Last time we saw colour being extended to different wavelengths, vision occurring at different speeds, and hearing revealing a world of insect communication hitherto unsuspected. These are fascinating enough, but here let's cover the senses which are completely unlike anything we've ever experienced.

Sounding

Though not the main topic of the book, as we saw last time, Yong gives some examples of how hearing can reveal surprising things about animal cognition. And the use of sound blurs the line between sensing and acting in other ways. Owls hunt using sound (though a directional accuracy of 1 degree hardly seems as impressive as Yong seems to think it is), and Yong speculates that cats might lie down to hunt to increase their sensitivity to ground vibrations. But of course some animals also use sound very much more actively. Sperm whales produce sounds of a truly staggering 236 decibels, which is frankly utterly ridiculous. What the hell are they using this for ?

Lots of things, probably. Sound like this could be used to stun or disorient prey. It could be for long-distance communication across entire oceans (elephants can use infrasound to communicate with other elephants several miles away). It could even be for sonar mapping of the ocean floor, with whales apparently behaving just as though they had such a map to work with. 

Yong explains in far more detail than Higgins just how staggeringly sophisticated animal sonar is. Bats desensitise their hearing out of phase with their chirping sequence to avoid deafening themselves, having to emit ~140 decibel blasts to achieve a decent range. They also focus their calls into narrow beams to extend the range further. Their vocal muscles are the fastest of any animal in order to produce sufficiently rapid calls. They can perceive differences in the return time of the echoes of just a single microsecond. This gives them information about their target which doesn't merely tell them how far away the whole thing is, but an imaging-like capability with literally millimetre precision. To aid this, their chirps aren't at just a single frequency, but sweep across a range of frequencies to get information on different spatial scales. There are even some bats which adjust the frequency based on the Doppler shift of their moving targets. And they adjust all this constantly to account for their own motion.

I find it nigh-on impossible to imagine what this must be like. It seems if anything to be like having a hand-held LIDAR system on you at all times. Does the bat have a mental image of its astonishingly complicated data, or does it perceive it as something else entirely ?

In one sense it doesn't matter. The important thing is the bat does get access to and makes use of this information. It uses the everyday familiar sense of hearing for a world view which is utterly alien to us. But all this is very demanding, so we may forgive the bats their occasional lapse into adorable incompetence :

They can distinguish two grades of sandpaper whose grains differ by half a millimetre, but will also plough headlong into a newly-installed cave door. They can discern flying insects by shape, but will go after a pebble launched into the air. Bats are fully capable of avoiding such errors. They're just not paying attention.

Then there are dolphins. Sound is even more potent underwater and dolphin sonar is astonishingly powerful. They can tell the difference between hollow metal cylinders that are externally identical but differ in thickness by the width of a hair. Once they've scanned an object without seeing it, they can identify it using vision alone - clear evidence that they really do understand the 3D shape of an object (with even better than visual fidelity) even if they're not using sonar to create an image per se.

And dolphins are literally living ultrasound scanners. They can tell if people are pregnant by yelling at them. They can work out the internal structure of their prey and sense their air bladders or if they have metal hooks inside them. 

Trying to imagine what it must be like to have such a sense is probably impossible. It seems very unlikely that sonar-equipped animals can process this immense level of detail in the same way that we process sound. Yong suggests that rather than being a sound-based version of vision, it might be more similar to touch - but none of our senses give us information about the internal structure of objects with anything like the capabilities of dolphin sonar, so no analogy is perfect. Of course, that's what makes it so fascinating.

Electromagnetism

While electric eels are famous for being able to electrocute potential threats, some fish can electrolocate. They create a weak electric field that surrounds them, in effect a weak current flowing through the water between electrosensors on their body. Any disturbances in the field - changes in conductivity due to different materials, changes in salinity - can be detected. For some fish this has become their primary umwelt, and then respond far more to the presence of metal in the water than they do an artificial light. Which makes sense if you live in a murky river where light isn't usually that important. To such creatures, metal shines like a light bulb, while actual light bulbs are nowhere near as impressive.

Like sonar, electrolocation can penetrate barriers. It's sensitive to both conductance and capacitance, is unaffected by turbulence. And it's instantaneous and omnidirectional, a big advantage over sonar, and may even afford something analogous to colour perception. The penalty is that creating a strong field is costly, so its range is far more limited : typically centimetres rather than metres, let alone anything further. The fish have compensated by evolving extreme agility and omnidirectional swimming capabilities, apparently oblivious to whether they're swimming forwards or backwards. What does your orientation matter if you can perceive everything in high resolution in all directions at once ?

However, while generating a field is difficult, sensing the fields deliberately generated by other fish is relatively easy. For communication purposes, electric fish can indeed perceive on scales of a few metres. And as with birdsong, the relevant information to them occurs on incredibly short timescales - microseconds. Nor is electroreception necessarily confined to fish, with evidence for a similar sense now being examined in bees and spiders. Like the ability to see ultraviolet colours or hear ultrasound, the "ultra" prefix is only a reflection of our own bias; it may, for many animals, just be normal.

What it's like, of course, is damned hard to say. Yong quotes some as likening it to touch. But the ability to have a direct sense of capacitance and conductivity is, as with sensing internal structure, really not something which has any obvious comparison.

Likewise with magnetic fields. It's well-known that some animals can navigate using the natural field of the Earth, and Yong says that turtles can sense both the inclination angle of the field and its intensity. They appear to be born with something akin to a magnetic map, enabling them to immediately navigate long journeys. It might not literally be a map as such, but a simple set of instructions : if the field is like this, go this way. But it serves the same purpose.

Higgins described two of the ways the magnetic sense could work but Yong offers a third : induction. Swimming induces a weak electric current in the water around it, and that current is affected by the magnetic field. So the animals may not be sensing the magnetic field itself but rather its affect on their electroreceptors. This would avoid much of the controversy around the other explanations, and could even apply to birds, which have conductive fluid in their inner ear which may respond to the Earth's magnetic field as they fly. Are they hearing magnetism ? We don't know. There's also evidence it's involved with their vision, so they may well be seeing it instead, or as well.

Yong closes this chapter with a look at the uncertainties, but comes across in a rather lazy footnote as having considerable skepticism about whether humans have an unconscious magnetic sense. Here I think Higgins does a much more thorough job in examining the work that's been done on this area, and it's a bit surprising to me that Yong would have kind of a problem with the notion of unconscious senses, let alone that they might not work well in all circumstances. Higgins addresses all these points quite thoroughly.

Hydrodynamics

This was the most interesting section of the book to me. While the sonar stuff is incredible, it's at least vaguely familiar. But while in What A Fish Knows (mainly concerned with cognition rather than senses) the author mentions the lateral line of fish that senses pressure changes in the water, Yong does a much better job of explaining just how amazing this is. It appears to be based on the sense of touch, but it's at least as different from our sense of touch is as sonar is from our sense of hearing. I'd go so far as to stay it's more like a direct sense of hydrodynamics.

But first, some more familiar uses. Like Higgins, Yong covers the star-nosed mole. He points out that touch can be sensitive at the molecular level, and notes that the mole in particular has an astonishingly rapid sense of touch - faster even than vision. So in stark contradiction to our intuition (at least mine), touch can be a sense that delivers as much information as vision does; after all, we don't receive the image we perceive directly, but the brain constructs it as our eyes continuously dart around. The mole can do the same with its nose, so it's entirely plausible that it creates the tactile equivalent of an image.

More familiar furry friends might be doing the same. Rats, mice and others can continuously move their whiskers several times a second, an action "delightfully known as whisking", which may be doing something very similar. Whiskers are of different lengths and orientations, and each one connects to different parts of the cortex. So again, building up something like a tactile image seems credible. 

It's marine animals where this difference becomes most apparent. Possessing a similar set of whiskers, blindfolded seals can sense the wake of a single fish from maybe as much as 200 m away, several minutes after the fish has passed. This, to a human, is altogether weird. It's a sense that provides as much information as vision, is similar to smell in that it provides information about the recent past, but it works more like touch. Seals can tell from hydrodynamics alone the size and shape of a fish, the direction it was swimming, and are so sensitive that, at close range, they can even feel the water pushed by the motion of their gills. Fish themselves, with their lateral line sensors that similarly detect the flow of water, can still form schools even when blind. Crocodiles too have special bumps on their snout that can detect flow, and apparently use this for detecting prey, mates, and their own young.

But hydrodynamic senses may not be limited to the water. Birds too have feathers that appear to be specialised for detecting airflow, while bats have hairs that do the same thing. And the most sensitive case of all is found in a spider, which can detect airflows as slow as a centimetre per minute. It can detect the absurdly small flows produced by its tiny prey, which itself may have similarly extreme powers of sensitivity. And they are, truly, extreme : "They can be deflected by a fraction of the energy in a single photon. These hairs are a hundred times more sensitive than visual receptor that exists, or could possibly exist." Why they have this outrageous level of sensitivity remains a mystery.

Conclusions

A running theme of the book is that sensory organs can be used for multiple purposes. In his conclusions Yong goes further, noting that different sensors can be unified much like in synaesthesia. For example, the platypus' bill contains both electrical and touch sensors, but with the neurons in its brain receiving signals from both together - suggesting it has a combined sense of "electrotouch". Mosquitoes have sensors that response to both temperature and chemistry, while ant antennas respond to touch and smell.

Sensors are also integral to cognition. We've seen examples of how behaviour can only be fully understood by trying to appreciate the umwelt even of very familiar animals, but it can go further than that. The brain is to an extent a prediction engine, generating what it expects to perceive and comparing expectations with reality, but how it does this - how, for instance, it can fill in details like missing or scrambled words, or remove repeated words - is a mystery. More on this when I eventually review Livewired.

While Yong doesn't go into the history of research in as much depth as Higgins, he more directly conveys the sense of frustration of certain researchers more clearly. Although he doesn't ever really got for the "lone genius" myth, it's clear that a lot of what's now taken as dogma was one dismissed within the scientific realm as quackery. Now this goes quite against my own instincts of academia but the book is so replete with examples of this that it has to be taken seriously. Perhaps there's something peculiar in the life sciences ? Then again, Yong only presents anecdotes. Someone should do a rigorous statistical history to see just how often apparently silly claims turn out to be true : what fraction of lunatic claims are just that, what fraction of the scientific community dismisses the results, how this manifests itself in papers compared to more popular writings, etc. But I digress.

I'll end with two points. First, Yong is a materialist, noting that stories about transferring our minds to other beings are simply impossible : 

"An animal's sensory world is the result of solid tissues that detect real stimuli and produces cascades of electrical signals. It is not separate from the body, but of it. You simply can't imagine how a human mind would work in a bat's body or an octopus's, because it wouldn't work."

This is a view I personally find to be extraordinarily mad. After making it clear in such detail that our perception of the world is not a "real" thing but dependent wholly upon arbitrary sensors, to then insist that our senses are directly perceiving reality itself is a truly strange claim. No, there is something out there that induces something in here, but to imply you've got a full picture of that whilst simultaneous admitting that other entities will experience something radically different is just silly nonsense, frankly. More on that here.

Finally, I began this summary/review with butterflies. As I said, Yong doesn't consider these explicitly, but there seems enough here to speculate as to how they perform such incredible feats of agility. First, their vision may not be very high resolution, but it's likely extremely fast, so they have in effect plenty of time to work out what's going on. They might have somewhat sharper vision than we guess, considering they can probably sense UV - which might at least help them further in distinguishing other butterflies from everything else, along with hypersensitive smell. And they can probably sense the tiny airflows from each other's wingbeats. The key lesson here is that there's so much more to the familiar world around us than we would ever normally suspect. It really is just as the title says : an immense world.

Review : An Immense World (I)

It's time to review another book about animal senses. This time I'm going to try and minimise any philosophical discussions and keep things as brief as I can.

... I tried, I really tried. But I still ended up having to split this one in two. In this first post, I'll give the obligatory review and cover what Yong says about some more familiar, everyday senses : smell, vision, pain and hearing. In the next post I'll look at the weirder, more exotic senses : sonar, electromagnetic, and hydrodynamic.

The Review Bit

I was a bit worried that being of such a similar topic, Ed Yong's An Immense World would be a bit too similar to Jackie Higgin's Sentient. It's not. There is some overlap, but the two are largely complementary, each providing content that the other misses. Yong is sometimes a bit more skeptical than Higgins, but more focused on the senses of animals themselves. Whereas Higgins' goal is explicitly to make comparisons with human abilities, concentrating heavily on their raw capabilities, Yong tries to grasp the animals' own experiences, which Higgins only touches on here and there. Yong tries very hard to work out not just what animals are capable of, but what's actually important and relevant to them.

Yong can sometimes be just a tad accusative and judgemental ("the once-popular series Game of Thrones"), but also has a more emotive writing style without sacrificing one whit of detail or being overly-schmultzy. Conversely, Higgin's greatest strength is explaining the agonising efforts required to do real, hard science, examining the research process itself in a thoroughly engaging way, whereas Yong largely sticks to reporting the current findings (though he does summarise the process by which these were obtained and doesn't shy away from controversy).

If I had to choose, I'd give it to Yong. Though not as in-depth as Higgins, he still conveys the uncertainty of the scientific process sufficiently well, and describes additional senses that Higgins, thanks to her own remit of comparisons with humans, does not. And, though he does have one or two throwaway remarks which are just plain silly (and some parts where I strongly disagree), I find his writing style just a nudge... better. I happily give this one an outstanding 9/10.

Right, so what's the most interesting stuff in this wonderful book ?

The Umwelt

This is a very useful concept of, quite simply, the sensory experience of the world. There is only one external world, but everything perceives this differently. You might recall my own amazement at how butterflies can perform astonishing feats of precision agility despite having much worse vision than most humans; the book doesn't look at this example directly, but provides a good many clues to understanding how this is possible.

Different umwelts mean that no organism has a unique claim on a special knowledge of reality itself. Photons perform supremely well in some situations but are useless in others. Just because vision is our primary sense in no way gives it any special claim to be observing the "true" reality, and the attempt to grasp other umwelts is intrinsically fascinating, however limited it must be.

This did make me wonder if the analogy can be useful culturally. Human sensory umwelts are mostly similar to each other, but our cultural ones - especially politically - can seem at times to be totally different. What to one person seems like a laudable improvement can be to others a terrible corruption; or more basically, an obsessive football fan experiences an entirely different world to a virtuoso violinist. Perhaps this doesn't offer anything more than the standard filter bubbles / echo chamber analogy, but it did make me wonder.

Smell

I have to mention this if only because Yong answers Higgin's irritatingly-unanswered question : are dogs really much better at smelling than we are ? Higgins gets bogged down in quantification and fails to come up with a clear answer, whereas Yong says it directly : yes. He emphasises that trying to quantify it is a mistake. Knowing how many neurons an animal dedicates to smell, or even how complex or large its sensory apparatus is, doesn't really tell you much about how much of its unwelt is smell-based. Dog behaviour, however, unarguably demonstrates that smell is much more important to dogs than people, even if the human sense of smell is traditionally underrated.

Imaging

Animal vision is weird. Although it's been reported, motion blindness in humans is incredibly rare. But apparently in spiders it's perfectly normal for some eyes to be unable to register motion at all. In animals with larger numbers of eyes, they don't all just provide imaging of different areas but do qualitatively different tasks : some give different resolution, some are dedicated to motion, some are different to different wavelengths, some are better are seeing high contrast features, some are specialised for low-light conditions, etc.

Scallops take this to extremes. They may have a sort of "distributed vision" system which each eye contributes only a small part of the whole. But weirdly, their brains are so simple it could be that they don't actually perceive vision at all - rather they've outsourced all vision-related tasks to the eyes themselves. The eyes might be triggering the appropriate response (seek food, close shell, etc.) without any processing by the brain. Yong likens this to our sense of touch, in that this too doesn't build up a 3D picture of the world around it. But it's a bit of an odd comparison, and perhaps better would be the taste buds in our internal organs - they register something but we don't perceive their stimuli. To be fair, the idea of "nociception" - sensations which are registered but are consciously unperceived - is dealt with elsewhere.

Still, I'm not much persuaded that scallops could exist in a world of perpetual blindsight. Likewise some animals appear to create colours they themselves cannot perceive, while many animals appear to have abilities we would expect to require high resolution optics even though they don't. 

This suggests there may be compensating factors (beyond their additional senses). While human vision is pretty near the top of the tree in terms of angular resolution, we're mediocre in terms of processing speed : dogs are about 25% faster, birds can be more than twice as fast, while insects can be almost six times as fast as us. So many animals have, in effect, a lot longer to scrutinise a scene and work out what they're seeing. For a fly, we may appear as nothing more than a blur, but it can take its time to work out whether that blur is approaching dangerously or just passing by.

One other example of how the different umwelt can affect our understanding of behaviour : cows. Unlike humans they perceive their visual field with equal resolution and attention across their whole field of view. So they don't turn their heads to watch passers-by not because they're lazy or uncaring, but because they just don't need to.

Remember that next time you're out in the countryside. Even if they don't turn to look at you, the cows are always watching.

Colour

Initially I thought that Yong gave a very nice overview of colour perception. I felt stupid for not realising that colour is generated in the same way was astronomers define colour : by subtracting one wavelength band from another. And two of the three wavebands that humans are sensitive to are surprisingly similar, which makes me wonder why we didn't evolved to sense more different wavelengths - an obvious question that Yong strangely doesn't raise.

... and thinking about it now, I got carried away (this is one reason I find doing these write-ups so useful). Yong also says in a throwaway statement that colour and wavelength are interchangeable but this is just not true at all*. Sure, there may well be a strong correlation between wavelength and experiential colour, but it can't possibly be the whole story, and so by the same token, neither can opponency (waveband subtraction). Yong doesn't much mention illusions either. 

* Similarly he claims audio frequency has a perfect correlation with perceived pitch. I'm not sure about this. However, he mentions this in the section on smell, noting that there's no way to match chemistry with perceived odour, so he does at least recognise the key aspect of qualia.

In fact, the more I think about it the worse this gets. Someone pointed out recently that after-image colour illusions are the result of activity in the eye which continues after the original stimulus. So Yong contradicts himself by saying that colour perfectly correlates with wavelength and then describing it as opponency, and also fails to demonstrate how this works given that there are plenty of examples in which the brain creates different colours from the same input signal. At the least, colour is not uniquely generated by instantaneous local signals : the perceived colour of one small region is affected both by what we saw previously and what we continue to see in the surroundings. Yong doesn't mention any of this.

But let's move on. While it's well-known that some animals can see wavelengths we cannot, Yong reveals that UV vision is downright common - in fact, it's the norm. I wonder if the shorter wavelength also helps compensate for their otherwise poor resolution, since the shorter wavelength means a smaller diffraction limit, but Yong doesn't mention this.

More dramatically, since colour is (I guess at least in part) formed by opponency, the more wavebands you're sensitive to, the more colours you perceive. Dogs and cats are dichromats (they don't see in black and white, but they do see fewer colours than us), humans are mainly trichromats, but a few of us and some animals can see four wavebands - which would give them the potential of seeing hundreds of times more colours than we can.

That sounds pretty awesome, but Yong pours a bit of cold water on this. Amazingly, gene therapy can allow trichromatic male squirrel monkeys to become tetrachromats, with resulting tests showing that indeed they could perceive new colours. But it didn't change their day-to-day behaviour very much. Likewise the handful of tetrachromatic humans don't seem to be going around continuously staggering with awe and their kaleidoscopic explosion of unimaginable rainbows, because for them, it's normal. Without colours having some known meaning, seeing new colours is apparently no big deal.

Of course Yong also covers the mantis shrimp. Popularised by the Oatmeal because it has no less than twelve colour receptors, sadly the comic was premature. Tests show it's not great at distinguishing colours at all. The latest theory about what's going on is that it might be sensing colours in a totally different, in some ways simpler way : each waveband doesn't overlap much with the others, so it might be seeing just twelve discreet colours instead. True, it can see circularly polarised light, but apparently the only things it needs this for are for other mantis shrimp - otherwise, this remarkable sort of vision isn't actually much of a perceptual breakthrough; its view of the world is certainly different to ours, but not especially advantageous.

As in Sentient, it's clear that sensory organs can be repurposed and might not always work the way we think we do. For instance, while the heat sensors of beetles work remarkably like photomultiplier tubes - turning minute signals into substantial ones - those sensors are unrelated to their eyes and function completely differently. How do they actually perceive this ? 

Snakes are even more of a challenge. They have heat-sensitive pits of such fidelity that their heat sense alone is enough to guide them to a specific body part of their prey when blindfolded. But while infra-red is just a longer wavelength of light, again the pits don't seem to have anything to do with their eyes. Do they perceive images from the pits directly ? Does the brain combine it as another colour with the visual signals from their eyes somehow ? Or do they sense it in a completely different way altogether, not forming an image of any kind ? We just don't know.

Pain

Yong notes throughout that animals sense what they need to sense. We've already seen examples where animals can sense but not perceive, and pain and temperature exemplify this. The pain we feel from spicy foods just isn't experienced by some animals at all, possibly because they simply don't need to sense that. Likewise temperature. Our sense of what's warm and cold is not an absolute; in all likelihood, animals that live in conditions that feel unsuitable to us don't feel so to them.

Here Yong makes another of his extremely silly statements. He says that the "unfortunate persistence of dualism" is responsible for people equating "subjective" with "woolly" and "imagined". I think this is just stupid. If anything, dualism would be more ready to accept that a subjective experience is no less valid or real than a physical one. Likewise, he says that the complexity of the brain may impose a lower limit on brain size below which consciousness is just not possible, which I think is very far from convincing (Planta Sapiens is next on my reading list).

The moral question here is of course which animals feel pain. Here Yong is much more cautious. I frequently see knee-jerk claims on the internet that of course all animals can feel pain, but we ourselves don't automatically register all damaging sensations as pain - and for the important reason that this can help us extricate ourselves from danger before the pain becomes distracting.

Because we know that we can sense some things without consciously perceiving them, it is entirely credible to suggest that some animals might have no conscious experience of pain at all. Yong errs strongly on the side of caution, noting that while crabs have apparently rudimentary nervous systems, their behaviour clearly suggests they experience pain nonetheless; squid appear to feel the effects of injuries with their whole body even when the damage is localised. About the only firm conclusion here is that the experience of many animals is clearly different to our own. The sentiment I get from this section is that we should presume but verify that animals can feel pain, and shouldn't expect it to be the same as our own - after all, many of their other senses are demonstrably different.

Hearing

Perhaps one of the clearest examples of the importance of the umwelt comes from the treehopper. These little insects produce a veritable plethora of extraordinary sounds, from rumble like an alligator to a "half moo, half scream", or a "hooting monkey with mechanical clicks". And like wandering into a silent disco, we're totally oblivious to the whole thing - not because the sounds are too faint or the wrong frequency, or because they're rare or exotic, but because they transmit them through the surface vibrations of plants rather than through the air.

When you realise an animal has all this extra information on which to base its decisions, you can't help but re-evaluate its behaviour in terms of intelligence. Yong doesn't dwell much on cognition in the book but he makes a couple of interesting remarks here. First, he describes in some detail how spiders respond to vibrations on their webs. But he also notes that spiders are fully capable of adjusting their webs to respond differently to different prey : e.g., when hungry they can increase the sensitivity to smaller items. There's an interplay here : the sensitivity of the web determines what the spider will hunt, but the spider can itself decide what the sensitivity should be. So I might be willing to cautiously revise my earlier opinion that a spider's web does not count as extended cognition.

Second, while songbirds typically have regular calls consisting of repetitive sequences, that's apparently not always what's important to them. Just as sight operates at different frequencies, so too does sound, with birds being able to distinguish very much finer structures in the sound than we can. Apparently, for some species it's this fine structure which they're listening to, not anything as crude as the major order of the notes. So while it's often claimed that no animal species has a true human-like language, this may only be a human bias in us examining things which are important from our perspective : what matters to the animals can be completely imperceptible to us. They have a wealth of different and extra information they're sending and receiving, and it's this we need to consider, not what we experience with our own senses.

Not that we should go nuts with this. Some responses do seem to be purely instinctual; while I found Higgin's claims about pheromones to be lacking in detail, Young says that some crickets have a hearing system wired directly to automatically produce responses to the song's of the opposite gender. At least some behaviours have no real thought (or at least no agency or choice) behind them at all.

Those are the familiar sorts of senses, then. I've glossed over smell because Yong doesn't really add anything new to Higgins. And I'm leaving touch for the next post, as some animals use this in such a radically different way that it's barely recognisable in terms of the kind of touch we're familiar with. Already, though, we can see that animal umwelts can be dramatically different from our own, with a running theme being that this is dependent on what animals need to be able to sense : penguins probably don't feel cold in Antarctica but rather feel normal; animals that suffer no great harm from losing a limb or a tail probably don't feel the agonising pain that we would in a comparable situation. Next time I'll look more at how radically different the umwelt can really be.