Blindsight : you don't know what you're aware of

This is seriously weird. Of course, it's well-known that the brain does a lot of extremely clever processing on the signals from your eyes, which is why there are so many possible optical illusions. But it can go much, much further than that. Your conscious mind isn't necessary for those visual signals - if part of your brain is damaged, you can still process the images unconsciously : vision without sight. The question then is, how much of this happens anyway ?

In 2008, Tamietto and Weiskrantz’s team put another blindsight patient through the most gruelling test yet. Unlike Daniel, he was blind across the whole of his visual field, and normally walked with a white cane. But the team took away his cane and then loaded a corridor with furniture that might potentially trip him up, before asking him make his way to the other side. “Despite saying he wasn’t able to see, we saw him shooting by on his very first attempt,” says Tamietto.

Importantly, the participant claimed that not only was he not aware of having seen anything; he was not even aware of having moved out of the way of the objects. He insisted he had just walked straight down the hallway. According to Beatrice de Gelder, who led the work, he was “at a loss to explain or even describe his actions”.

Only in very rare circumstances do they come close to being aware of what they are seeing. For instance, one subject was able to distinguish movement in fast, high-contrast films; he described it as being like “a black shadow moving against a completely black background” – a “sense of knowing” that there was something beyond. But even then, he could not describe the content itself, meaning that his experience lacked almost everything we would normally associate with vision.

Enter the mad scientists :

To test their ideas, scientists can use a form of non-invasive brain stimulation that disrupts different brain regions, in an attempt to induce a reversible form of blindsight in healthy participants. The technique is called “transcranial magnetic stimulation”, which uses a strong magnetic field to scramble the neural activity underneath the skull.

The experiment began with Allen placing a magnet over the back of my skull, just above V1. Next, he began applying the magnetic field for short intervals at increasing strengths. After Allen had found the right power, I sat in front of a computer screen, and he flashed up pictures of arrows for a split second: my job was to say whether they pointed left or right. The pictures were sometimes timed with the TMS signals causing the temporary blindness – and like Daniel in those original experiments, I often saw nothing and felt that I was guessing. Nevertheless, once I had finished, Allen told me that I had answered many more correctly than would be expected by chance alone, suggesting the TMS had succeeded in giving me blindsight.

[I'd also add that this has important epistemological consequences. We usually think of ourselves as "knowing our own minds", that if we think we're happy or sad then no-one can refute this but ourselves. But if we don't even know what we're sensing, then our self-knowledge can be much worse than we'd like to think.]

http://www.bbc.com/future/story/20150925-blindsight-the-strangest-form-of-consciousness

Aphantasia : a weird lack of mental imagery

Sounds like the name of a ghostly Disney princess but actually it's much more interesting than that :

The former president of Pixar and Walt Disney Animation Studios says he has a "blind mind's eye". Most people can close their eyes and conjure up images inside their head such as counting sheep or imagining the face of a loved one. But Ed Catmull, 74, has the condition aphantasia, in which people cannot visualise mental images at all.

I don't need to close my eyes - is that normal ?

Eventually Ed realised he was not alone and that, perhaps counter-intuitively, some of the greatest talents in animation could not visualise either. Oscar-winner Glen Keane, who created Ariel (The Little Mermaid), also has no visual imagery. Ed told the BBC: "He is truly extraordinary, he's one of the best animators in the history of hand-drawn animation. "[And] he said that he could never visualise either."

The homework also revealed stark differences between two artists and good friends of Ed's who had worked on Frozen. One can see an entire movie in his head and play it backwards and forwards and never needs to see a movie twice because he can visualise it. The other cannot see anything at all.

Okay, I can't do that.

He added: "People had conflated visualisation with creativity and imagination and one of the messages is, 'they're not the same thing... you would think if a person could visualise, they're more likely to be able to draw. [But] If you open your eyes and you take out a pencil and pad, how many people can draw what they see? The answer is a very small number, so if you can't draw what is in front of you then why would we expect that you would be able to draw what you visualise?"

And very few people can draw something as common as a banknote from memory. To some extent mental images could be the brain providing a sense of the experience of visualising something without providing the visual cues themselves, as in the cases where impossible occurrences in dreams seem completely normal. We could be, in effect, imagining that we're seeing all the details but really we're not, a sort of internal blindsight (where the brain receives visual information and can produce accurate responses to it but the conscious mind is unaware of it). So that would mean :

• Hallucinations are when you mistake your internal visualisation for external perception.
• Blindsight is your brain forgetting to create the internal visualisation stage - you perceive things, but not in the usual way.
• Internal hallucinations are when your brain tells you you're seeing something in your mind's eye but actually you're not.
• Internal blindsight would be when you hallucinate that you're having a hallucination, that is, you may think you're not seeing something internally but actually you are (hence the surprising drawing skills).

How on Earth you would know if someone is really able to see something internally versus them just thinking that they can (they might be shite at drawing), I have no idea. All I know is that if you can't ever be sure that what you perceive is real or external or internal or you brain fooling you into confusing these states, then defining knowledge is clearly flippin' complicated.

My head hurts.

'My mind's eye is blind' - ex-Pixar chief

The former president of Pixar and Walt Disney Animation Studios says he has a "blind mind's eye". Most people can close their eyes and conjure up images inside their head such as counting sheep or imagining the face of a loved one.

Some ramblings about consciousness and plants

One of Gizmodo's better articles, because it's entirely quotes from different experts and not written in their usual, highly irritating, "here's what you must think about this" style.

Consciousness is something where our language seems inadequate to the task. We all know what it is, but defining it is nearly impossible. "Awareness" could refer to any kind of sensory stimuli, but that doesn't adequately convey the experience of thinking - and it can also be used more casually to refer to consciousness itself. The thing about thinking is that it's very hard, probably impossible, to prove that other people (much less plants or computers) are having a similar experience. Oh, we can measure neural activity to the nth degree, but that won't tell us anything about what it's like to be someone else or a cat or a flower or a piece of mouldy cheese.

We don't need external senses to be conscious anyway, at least not all the time, because clearly we do a lot of thinking without reference to what our current senses are telling us. I'm writing this against the backdrop of G+, which currently shows pictures of a bird, the moon, and a spam post in a badly-moderated community. I'm not thinking very much about those while I'm writing this.

Recently I was thinking about blindsight, where people receive visual input from their eyes but it isn't processed by their conscious brain. They can accurately respond to that stimuli, but they aren't conscious of it.
http://www.bbc.com/future/story/20150925-blindsight-the-strangest-form-of-consciousness
I'm wondering if this isn't as strange as is first seems : maybe we're all doing this almost, but not quite, constantly. I don't mean that we have weird mystical woo-woo hunches based on mysterious ESP or anything like that. Rather I mean that when we start imagining things (when we're awake and in the case of visual thoughts, with our eyes open), we're no longer conscious of the external world in quite the same way. Some other part of the brain takes over so we don't trip over ourselves when we go to get a cup of tea and start thinking about data reduction or exploding whales or whatever. In true daydreaming, rather than more causal thoughts, this process is taken much further, but even with random mental images it seems to take hold. At least it does for me anyway. Blindsight, then, only seems strange because it's permanent and specific to one sense, rather than regular (but fleeting) and generic to all senses as in the case where our minds wander.

This kind of mental perception is normally distinctly different from our conscious perception; it's far more dreamlike. But, this all being an extremely fuzzy spectrum, you can have dreams and thoughts which are very close (or even indistinguishable from) conscious perception, and states of consciousness which are more dreamlike. So, consciousness can't be awareness or perception in that sense. It has little to do with the external world in itself.

Memory and knowledge are of no help either because we haven't got much in the way of a good definition of either of them. Take the overflow pipe in my bath. When the water level is too high, it drains away. This very simple device responds in a predictable way to an external stimuli. Does it "know" the water level is too high ? Does it "remember" what to do in the event of too much water ?

Of course not, but it's a very short step into realms of total confusion. Create a more complex device that responds to multiple events, or code that deals with multiple if-then loops. At what point do we say that they are making a choice ? Are we just elaborate versions of overflow pipes : an incredibly complex set of variables that nonetheless run according to fixed, inviolable rules ? If so, in what sense are we conscious whereas plants and pipes and bits of dandruff are not ? Does a calculator or a flower have the sort of internal perception we ascribe to ourselves ? How could we ever prove it ? What sort of consciousness is it ethically acceptable for us to destroy, i.e. why eat plants but not animals ? Why smash calculators but not kill people ?

The Universe is very confusing and I don't like it. For my part I throw up my hands and declare, "Bugger if I know. Look, I'm conscious, you're conscious, he's conscious (even if he's a bit of a dick), that fluffy rabbit is conscious, that rock isn't but I ain't sure about the suspicious-looking daffodil in the back. What's that ? You ask why ? Because I said so, that's why."
https://gizmodo.com/are-plants-conscious-1826365668

In two minds

Recently I accomplished a long-term goal by finally articulating what I think free will really is. In my view, it means the capacity for mind over matter : for our thoughts, the things we subjectively experience, to change our behaviour and thus give us a limited measure of mental control over the external, objective world. I see consciousness as a sort of field-like thing, highly localised to within our own brain, and only able to affect (and be affected by) the material that gave rise to it. This then prevents any sort of mysticism, albeit while keeping consciousness itself thoroughly mysterious.

Thanks to a comment on that post, I started pondering my way down a rabbit-hole of implications as to what this view might mean. I'll give a shout-out here to this very nice blog : from what I've seen, I disagree with much of it but find it hugely interesting and provocative. So now I'm wondering if, though the idea of field consciousness seems sound enough in itself, the same can be said for its consequences.

What started to nag at me was the idea of split brain memories. This is the bizarre finding that some animals appear to store and access memories in different sides of the brain, depending on how they were formed : e.g. an animal seeing something with one eye responds differently than the case of seeing it with the other eye. And this phenomenon occurs in humans too. When certain connections between the two hemispheres are severed (as is occasionally done through medical procedures to treat severe epilepsy), patients behave as though they have two distinct minds, with one side trying to physically stop the other from doing things. In humans this is . Example 1 :

When Sperry and Gazzaniga presented stimuli to the right visual field (processed by the speaking left hemisphere), the patient responded normally. However, when stimuli were presented to the left visual field (processed by the mute right hemisphere), the patient said he saw nothing. Yet his left hand would draw the image shown. When asked why his left hand did that, the patient looked baffled, and responded that he had no idea.

In some animals a similar condition is perfectly normal. Example 2 (from "Other Minds", which I briefly review here) :

The pigeons were trained to do a simple task with one eye masked, then each pigeon was tested on the same task while being forced to use the other eye. In a study using nine birds, eight of them did not show any "inter-ocular transfer" at all. What seemed to be a skill learned by the whole bird was in fact available to only half the bird; the other half had no idea.

And it's not a straightforward binary condition either. Example 3 (also from "Other Minds") :

An octopus trained on a visual task using just one eye initially only remembered the task when tested with the same eye. With extended training, they could perform the task using the other eye. The octopuses were unlike pigeons in that some information did get across; they were unlike us in that it did not get across easily... The special kind of mental fragmentation seen in split-brain humans seems to be a routine part of many animals' life.

It's also worth recalling blindsight, when visual information is processed only subconsciously; reverse blindsight, when no subconscious processing is applied to the received images such that they simply make no sense, like being unable to read text but applied to everything; and flatworms, who can apparently literally eat memories.

So what's going on here ? Does this point towards an even more materialistic interpretation of consciousness, where it's strictly limited to matter over mind and never the other way around ? Naively, I would think that if consciousness is any sort of field, be that generated by the brain or only received by it, it ought to be able to convey information throughout itself. It seems extremely strange to say that it could only access information with such extreme locality; that part of the field would know things that the rest didn't.

Of course, idealism has no problem with this since everything is imaginary anyway. Illusionism denies consciousness exists, so again, no problem. Compatibility with panpsychism is harder to determine, since it's not obvious how consciousness is combined from its constituent atoms. But it definitely does appear to be a problem for any dualistic field theory of consciousness, be that generated or received by the brain.

However, we also know about blindsight. And as I've suggested, this may not be so uncommon - we all run on autopilot sometimes, lost in thought but for the most part still managing to avoid bumping into tractors and stray hippos. So our brain is definitely capable of sophisticated data processing without conscious intervention. Maybe, then, the physical splitting of the brain simply prevents certain memories from reaching the consciousness at all, so that it's handled by the brain's other faculties that don't require awareness. After all, we're not exactly fully aware of all the signals our brain sends out : we don't feel nerve impulses sent to our arms or lungs or feet, yet they all manage to get by perfectly well without is. 

This makes it at least conceivable that someone could draw something they genuinely weren't aware of, without invaliding conscious field theory (if I may give it an unnecessarily grandiose title) at all. I think this idea would depend on how far it can be pushed - could someone solve differential equations without being aware of them ? A bigger and more fundamental problem might be that something has to make a choice : part of the brain has to decide whether or not to commence drawing, and to be unaware that this choice was made seems extremely strange. The part of the brain that enacts drawing must furthermore understand the instruction to draw... all in all, it would have to behave suspiciously similarly to someone who was fully conscious themselves.

Of course, splitting the brain could just outright split the consciousness. This doesn't invalidate its field nature though : the two halves of the brain would then either generate (or a receive) an additional consciousness to the original state, with the original also being changed by the change of its receiver/generator equipment. And, since they're split, each consciousness will only ever report the experience of being one person, by definition, regardless of whether it does so in writing or speech. So an individual will never feel like they're two people, even if there are multiple consciousnesses coexisting inside their singular head.

This seems perfectly reasonable in cases of medical intervention, but bizarre in the animals that are like this anyway : why should a pigeon have multiple awarenesses ? Of course it might, but this doesn't feel very plausible.

A third possibility relates to how consciousness, in this model, interacts with the external world depends on the exact nature of its receiver/generator. The conscious field is mediated by the brain, so that if the brain is damaged then the field can't interact with the external world in the same way : even if the connections to the arms, hands etc. are themselves undamaged. In this interpretation the field itself would be fine, with no change in awareness or memory, just unable to control the body as it did previously. Likewise, an animal could exist in this state perfectly naturally, without surgical intervention or multiple consciousness in its head, just unable to control itself as a more naïve interpretation would expect. It would be a bit like being left-handed, only taken to an extreme : not unwilling or unaware of what was going on, but simply unable to express a particular memory or perception.

This would seem to be unsatisfyingly strange and quite unprovable, however, it is perhaps not as weird as it might first appear. Recall reverse blindsight, where those restored to sight after a long absence are unable to "read" the world around them, to perceive it but not assign anything any meaning. Or foreign accent syndrome, or dyslexia - it is quite possible to perceive something, to be aware of it, and not understand it, and thus not be able to communicate (i.e.) express it. The major difference being that in those situations people are generally aware of the difficulty.

In short, explanations could be :

• The brain processes some information without it ever reaching the conscious mind. The brain would have to receive external information, decide on a course of action, and then enact it all without conscious intervention. To some extent it can do this anyway, but it raises the question of how far this can go - and of course, ultimately whether consciousness is really required at all.
• Multiple consciousness coexist alongside one another. Each is singular and has access (usually) to the same basic information, but each can only perceive itself. This would be radically at odds with how we normally perceive ourselves, and one wonders why a pigeon would need to have multiple minds - and why I can't let a secondary consciousness take over when I'm bored.
• There is only one conscious field and it is always privy to the memories of the entire brain, but since the field's interaction is governed by the material substance of the brain, its capabilities can be changed in surprising ways. The mind may be perfectly aware of what's going on but unable to express itself due to the limitations of the mediating brain.

I think it fair to admit, though, that while this phenomenon certainly doesn't rule out a consciousness as a field, it does lend credence to a more materialist, illusionist perspective : passive consciousness. Either way, it points to a clear separation of consciousness and memory. Now I pointed that out in the original post, but I think this still leaves a distinct... uneasiness. Yes, there's more to identity than memory. But if I lose all my memories, can I really still call myself the same person ? If my "soul", for want of a better word, need not even be aware of anything I've ever done, in what sense is it really "mine" ?

I don't know. For my part this isn't nearly enough to persuade me that illusionism is anything other than mad. But consciousness does seem, at the very least, to be even stranger than we give it credit for - and that's saying something.

Review : An Anthropologist On Mars

Continuing my trend of picking up cheap books I would not otherwise give a second glance at. A random assortment of seven unusual neurological conditions, all wrapped in a silly title* and a proverbially bland cover ? Doesn't seem like my thing at all, really.

*It isn't really, of course. I just tend to prefer more direct sales pitches.

(Also, as an aside, never use Goodreads. The comments there have an incredibly high fraction of morons.)

Once again I was delighted to be wrong. What made me decide to give it a go was the philosophical aspect. Rather than stating the surface conditions, the behavioural problems and the details of neurology (which even in the outstanding The Idiot Brain did at times feel like a litany of which bit of the brain does what), Sacks concentrates on the subjective aspect of what it's like to be someone experiencing these conditions. Just because we can't know for sure doesn't mean we can't try.

Sacks never falls into the obvious trap of creating a freak show. He writes with warmth and compassion for what are at times tragic conditions, emphasising that these are real people as entitled to dignified treatment - both medically and socially - as much as anyone else. The philosophical aspect is kept very much implicit (he only mentions qualia once), but it's no less interesting for that.

Overall, what emerges is a world view far more subjective than we often suppose. That is not, to nip the idea in the bud, at all to say that reality itself is subjective - it isn't. But our perception of it is essentially totally subjective. What we perceive has to be broadly self-consistent, but there's no particular reason our internal reality has to be anything like the way it happens to be. For many people, their entire inner world is radically different to that of the rest of us.

Perhaps the easiest examples of this to understand concern vision. Sacks details an extreme case of a painter who, through an accident, overnight became entirely colour blind. Not just the usual red-green colour blind, but perceiving the world in something like greyscale. But not exactly like slipping on a pair of nightvision goggles : something altogether stranger was at work, almost like perceiving a colour entirely different to anything we usually see, with a contrast range that was extremely sensitive to context. Initially tragic for an artist dependent on colour, he eventually came to terms with - and even embraced - living in a fundamentally altered world.

Motion blindness is sadly mentioned only in massing, but is even weirder. Like a reverse T-Rex, sufferers cannot sense motion. They can see objects, but their brain is unable to register movement correctly. When something as fundamental as movement is perceived subjectively, the idea that our eye is something equivalent to an objective camera would seem to be nothing more than an exceptionally common but blatant fallacy.

Just how far this goes is demonstrated by a patient who had his vision restored decades after going blind as a child. We're all familiar with optical illusions, but we tend to think of them as demonstrating some weird quirks. Not so - they actually reveal just how fundamentally subjective our vision is.

I once had my my ears bunged up for a few days. After they were syringed - a pretty icky and thoroughly weird experience - I was expecting it to be like that moment when your ears un-pop after a flight, or if you've got a bad cold : fully restored to normal in a singular moment of blessed relief. But it wasn't like that at all. Initially I was worried something was wrong. I could hear all kinds of strange noises, which I gradually realised were the doctor adjusting some equipment way across the room. The slightest sound was clearer and more distinct than I'd ever experienced before, a strange but not unpleasant experience. Pretty soon though, my brain decided this superpower was unnecessary and after a few days everything was normal again.

In the case of vision, it seems that something analogous can occur if the loss was only for a short period. But with a period lasting decades (perhaps especially with the loss occuring in early childhood), things are not the same at all. The brain loses all of its heuristics for making sense of the world. Far from seeing the world directly, it's more like we're constantly reading the images around us, transforming raw shapes and colours into meaningful objects : tables, kittens, boobies, dinosaur ninja pirates, and so on. Without these heuristic tricks, the poor patient had to learn to read the world essentially from scratch. As with hearing, there wasn't a moment of revelation, no pulling back the veil - but things were, unfortunately, so much worse than that.

With a lifetime of exploring the world through touch and sound, vision meant very little to him. His was formerly a world of time, with no concept of distance. Motion blindness ? With even space itself being a new idea, he had far more difficult challenges. Suddenly this new sense was thrust upon him and the experience was overwhelming, particularly as everyone around him fully expected an awakening, an instantaneous moment of clarity, and could not understand the scale of the change he was experiencing. Even perceiving shapes and colours was difficult. He went through a highly variable process, sometimes able to perceive colour but not shape. At other times he experienced blindsight, the condition in which the brain processes the visual signals unconsciously, with no conscious awareness of it at all.

But blindsight may not be as weird as his generally condition. Arguably we all do something like blindsight when we daydream, but what he had most of the time was the reverse of this : his brain was not doing any of the unconscious processing of the visual signals. He could see, consciously, a flower or his wife but have absolutely no idea what they were. The visual information was all there but simply had no meaning. He did, to some degree, eventually learn to read the world visually, but never achieved the fluency that most of us take for granted.

"Meaning" is a running theme throughout the book, and goes far beyond vision or the other senses. Sacks focuses particularly on autism. While the sighted usually take the idea of distance for granted, most people are able to take the idea of meaning itself as a given (the only time we'd try and define it is as a philosophical exercise). But the autistic, and those with similar conditions, do not have this. They can know things without understanding them in the slightest. They might "know" what being happy is but never experience it for themselves. Or, less debilitatingly but no less strange, they may be completely enthralled by (say) music or drawing, but have little or no understanding of anything else. They can have normal (or sometimes extreme) intelligence and emotional awareness but only in very specific areas, with otherwise vacant individuals becoming essentially non-autistic when confronting their field of interest. Sometimes they can learn to judge the emotions of others, even predict how they'll react, but still have absolutely no idea of why people react in a certain way. They have no in-built theory of mind at all; everything they do to understand people is done consciously.

There are definitely hints here that intelligence can be remarkably specific. Rather than being a general property, intelligence itself - not just knowledge, but the very capacity for understanding and problem-solving - can be limited to incredibly specific areas : music, mathematics, dance, animal psychology. It's not that they're just not interested, it's that they fundamentally cannot understand anything outside a narrow area.

Often this is simply tragic - there's no compensating ability, no way for them to productively interact with the world. Their seems a great deal of controversy over whether they're emotional but unable to express themselves or genuinely lack emotions, or if they're triggered differently to the rest of us. Many need constant help. But others do manage to get by by themselves, and sometimes achieve great success - albeit not without issues. There's more than a little of the stereotypical scientist about the whole thing :

What one does see in Temple's writings are peculiar narrational gaps and discontinuities, sudden, perplexing changes of topic, brought about by Temple's "failure to appreciate her reader does not share the important background information she possesses". In more general terms, autistic writers seem to get "out of tune" with their readers, fail[ing] to realise their own or their readers' state of mind.

A more perfect description of an academic paper I cannot imagine. Small wonder that the negative stereotype of a scientist is someone broken ! But then of course we can flip this around : as an astronomer, I just "don't get" why more people aren't thrilled about galaxies. I don't get the appeal of team sports or why you'd rabidly follow the antics of brain-dead celebrities. That, of course, is very different to lacking a "theory of mind" - even the most inane socialite could probably at least realise when I'm thrilled about some discovery without understanding it, just as I could understand said socialite's idiotic glee at the new outfit some washed-up actor has dredged up.

Nonetheless, there are similarities between obsession and autism. While it's obvious specialist knowledge does not automatically translate into expertise in other fields, perhaps it's more fundamental than that. Perhaps intelligence is not some global, general property at all, but a multiplicity of abilities, a plurality of interests that can be aligned in remarkably specific ways. The evil genius may be more than about an inability to overcome personal bias : someone could be conceivably exceptionally talented at gaining power but have no clue whatever as to how to use it.

Sack's book is a mixture of the tragic and the hopeful. Some of these conditions are simply awful and ultimately fatal. But others can, if managed properly, bring advantages as well as disadvantages, with individuals having unique and valuable perspectives and abilities. I suspect Sacks would have some sympathy for the idea of "neurodiversity", with at least some of the autistic fiercely defending their condition as an integral and important part of their identity. Some conditions undoubtedly do need treatment. Others may only need compassion and acceptance.

Now you see it, now you... oh...

You may have heard of blindsight, where the eye functions perfectly, the brain processes the signals... but doesn't deliver them to the conscious mind. In such a state, people can avoid obstacles whilst being unable to see them. I've often wondered how much this goes on normally, i.e. when we start imagining things we don't start walking into walls. Turns out there's an even more subtle aspect that bridges the gap between full blindsight and normal consciousness.

A magician sat at a table in front of a group of schoolchildren and threw a ball up in the air a few times. Before the final throw, his hand secretly went under the table, letting the ball fall onto his lap, after which he proceeded to throw an imaginary ball up in the air... what was truly surprising is that more than half of the children claimed to have seen an illusory ball leave the magician’s hand and disappear somewhere midway between the magician and the ceiling. This was clearly an illusion because on the final throw, no ball had left his hand; the children had perceived an event that never took place.

My intuition about the role of my gaze was correct, for the illusion was far less effective when I looked at my hand that was concealing the ball. These findings reveal some interesting insights into the illusion. They illustrate that the illusion is mostly driven by expectations, rather than perceptual afterimages. More recently, we have shown that even when you simply pretend to throw a ball up in the air without ever having thrown the ball for real, more than a third of people still experience the illusion. In some ways, we are behaving like dogs who run after the stick their owner simply pretends to throw.

So you see things because your brain is expecting to see them and fills in the gaps. This is weird enough, but we're more or less familiar with this from optical illusions. What's even stranger is that consciousness is operating on different levels with regard to perception. Some levels are indeed fooled by the expectation illusion, but others aren't.

 Although most of our participants experienced an illusory event, the eyes were not tricked. When the ball was thrown for real, most of the participants managed to look at it when it reached the top of the screen. During the fake throw, participants claimed to have seen the illusory ball at the top of the screen, but they did not move their eyes there, which suggests that our eyes are resilient to the illusion. This result took us by surprise, but it dovetails with several other findings and highlights another truly amazing feature of visual illusions.

Richard Gregory and colleagues have shown that if participants are presented with a hollow mask and are asked to point to the nose, they point to a location outside the mask. This is because they consciously perceive the face as being solid. However, if you ask them to quickly flick the nose, their hand moves inside the mask and touches the correct location. This is because flicking is a visually guided action that is driven by the dorsal stream, the visual system that requires reliable spatial information, and thus is not fooled by the illusion. Our eyes are also driven by the dorsal stream, so even though your conscious perception has been fooled by the illusion, your eyes have not.

What's perhaps most impressive of all is that your perception isn't what's happening right now. All the processing required takes time - about a tenth of a second. The brain, amazingly, is able to extrapolate all the information it receives to correct for this by extrapolating into the future. Everything you see is your brain's best guess as to what the world is likely to look like right now. It's accurate enough to catch fast-moving balls and other objects... in a crude but literal sense, we're living in our own simulation.

Neural signals are initiated in the retina and then pass via different neural centers to the visual cortex and higher cortical areas, which eventually build a mental representation of the outside world. Neural processing is not instantaneous because neural signals are passed along neurons at a finite speed. It takes about a tenth of a second for the light registered by the retina to become a visual perception in the brain.  Let me put it in context: if you are walking at a modest speed of about one meter per second, a tenth-of-a-second delay will result in you perceiving the world as lagging 10 centimeters behind you. This is quite hard to believe because you simply do not experience the world as lagging, and such a perceptual error should certainly result in many early-morning collisions. 

It is only once you start thinking about some of the huge day-to-day challenges our visual system constantly faces that the true wonders of the brain start to emerge. Our brain uses a really clever and almost science-fictional trick that prevents us from living in the past: we look into the future. Our visual system is continuously predicting the future, and the world that you are now perceiving is the world that your visual system has predicted to be the present in the past.

A Magician Explains Why We See What's Not There - Issue 70: Variables - Nautilus

Norman Triplett was a pioneer in the psychology of magic, and back in 1900, he published a wonderful scientific paper on magic that, among many other things, discusses an experiment on an intriguing magical illusion. A magician sat at a table in front of a group of schoolchildren and threw a ball up in the air a few times.

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.

Put your thinking cap on

Working memory is where your mind keeps temporary information, and has been described as the "sketch pad of the mind". You need your working memory to write down a phone number as someone reads it out to you. Problem-solving, mathematical calculations and decision-making all involve working memory too. Robert Reinhart, an assistant professor at Boston University, and one of the researchers, says: "It's essentially where consciousness lives." 

Working memory declines naturally with age. But the older adults' performance improved with brain stimulation. Dr Reinhart said: "We can bring back the more superior working memory function that you had when you were much younger. 

The team at Boston University, in the US, gave people in their sixties and seventies the working memory of someone in their twenties. The effect lasted at least 50 minutes after the stimulation stopped. But larger studies are now needed to see if stimulation could help people in the "real world" or in treating brain diseases like Alzheimer's.

According to a podcast on the Financial Times, the 50 minutes was how long the study was scheduled to last, so no more measurements were taken after this. The researchers expect the effect to persist for "hours at least".

The study showed that brainwaves become out of sync - like musicians giving a disjointed performance - as we age. The team at Boston University started by recording people's brainwaves with an electroencephalogram. They used electricity stimulation - specifically high definition transcranial alternating current - to strengthen and resynchronise the brainwaves. 

Dr Reinhart says: "I think it is possible to sort of turbocharge even normal, healthy, cognitive functioning people, including young people. "But the largest improvements appear in the people with the greatest deficit at baseline... people who are struggling the most."

I wonder what other effects might be possible. For instance it's possible to induce blindsight by wearing magnets.Perhaps a Penfield mood organ or a dream machine is not so outlandish...

Precise brain stimulation boosts memory

Using electricity to precisely stimulate the brain can boost people's working memory, a study suggests. The team at Boston University, in the US, gave people in their sixties and seventies the working memory of someone in their twenties. The effect lasted at least 50 minutes after the stimulation stopped.

Listening To The Voices In Other People's Heads

Here's a very nice long read from the Guardian about trying to understand what's really going on inside our heads.

Recently I concluded that any attempt to understand what consciousness actually is is likely hopeless. Trying to understand what we mean by experience when literally all we have access to is experience is inevitably circular. But the effort itself isn't fruitless. We can all of us have different preferences for what we think is going on – non-physical, spiritual, purely materialistic – and that discussion is often productive, if only in understanding how people reach radically different conclusions from the same data. More promisingly, it gives us a better handle on how we go about defining things, how we grapple with the imperfections of mapping language onto reality.

But there were also two more directly productive outcomes described in the Aeon essay I looked at last time. One was that we could understand in some detail the neural correlates of consciousness, the processes occurring within the brain that are associated with what we think and experience. The second, somewhat subtler issue, was that we can still take a reductive approach to different aspects of consciousness : we can describe it in terms of different levels and content, and in so doing get back to something we can discuss in familiar scientific terms. Just as we don't have to worry about what a quark is really made of to understand how it behaves, so too we can tackle the subject of minds.

The Guardian piece is complementary to the Aeon article in that it leans more heavily in this direction. As it begins :

A neuroscientific perspective on consciousness might tell us something about its neural correlates, but it is unlikely to tell us much, if anything, about the nature of thoughts or the textures of inner experience; it’s the wrong tool for that job. So what might we learn about consciousness if we gave more weight to the view from inside the experience – the phenomenological viewpoint ?

For example, it describes William James' comments on something I've found extremely strange for many years :

“Suppose we try to recall a forgotten name,” he writes. “The state of our consciousness is peculiar. There is a gap therein; but no mere gap. It is a gap that is intensely active.” A sort of ghost of the absent name haunts the empty space in our consciousness, he suggests, making us “tingle with the sense of our closeness, and then letting us sink back without the longed-​for term”.

He goes on: let someone propose a candidate for the missing name, he suggests, and even though we have no consciousness of what the name is, we are somehow conscious of what it is not, and so summarily reject it. How strange! Our consciousness of one absence is completely different from our consciousness of another. But, he asks, “how can the two consciousnesses be different when the terms which might make them different are not there ?” 

The feeling of an absence in our minds is nothing like the absence of a feeling; to the contrary, this is an absence that is highly specific and intensely felt. Thoughts glimpsed from some height of awareness but somehow not yet formed, much less put into words or images – this is the subtle terrain James invites us to explore with him.

I very much agree with this. It's always seemed weird to me how we can think in complete sentences. We – or rather I, and I'll get back to why the distinction matters later on – don't really sense the words falling into place, they just come out like that. Clearly they must have been assembled at some point, but somehow this happens without us knowing about it ! 

Perhaps even weirder is that sensation when grappling with a complex problem : at the point of reaching a possible solution comes a very distinct sensation of raw, unstructured thought, some quasi-awareness that the answer has been reached but without being able to articulate it. That moment is crucial. If interrupted in this momentary phase, the proto-thought may be lost entirely. But if it's seen through to completion, the thought crystallises into language : something we can easily memorise, recall, and communicate with others.

Much of the article is then concerned with whether we can access this much lower level of thinking in some way. If we want to understand consciousness, can be go beyond language ? Maybe that's too ambitious. To start with, can we at least access thoughts at the stage that they become coherent ? 

Step forth, Russell T. Hurlburt :

For half a century now, Hurlburt has been scrupulously collecting reports of people’s inner experiences at random moments – and just as scrupulously resisting the urge to draw premature conclusions. A die-​hard empiricist, he is as devoted to data as he is allergic to theories... I’ve been going around with a beeper wired to an earpiece that sends a sudden sharp note into my left ear at random times of the day. This is my cue to recall and jot down whatever was going on in my head immediately before I registered the beep. The idea is to capture a snapshot of the contents of consciousness at a specific moment in time by dipping a ladle into the onrushing stream.

What he is after in his research is the “pristine inner experience”, by which he means a sample of human thought “unspoiled by the act of observation or reflection”. Like James, Hurlburt acknowledges that the act of recalling and describing an experience is bound to alter it, but he believes that his method can get us closer to the uncontaminated ideal than any other.

In some ways this should be extremely easy. Again, we definitely do have coherent, structured, linguistic thoughts, and writing those down is straightforward enough. Indeed, as this fascinating BBC article describes, it's even possible to read these directly from the brain. This doesn't require participants to mentally try and speak : to a degree, thoughts can now be extracted at a lower level than this.

But then again, even the most fully-developed thoughts can be extremely slippery. As I've noted, once you put pen to paper you engage in a sort of self-conversation, thoughts and beliefs becoming highly flexible once you start reflecting back on them from an external input. Take a thought from in here and put it out there and it inevitably changes, even if only just a little. 

Still, this can largely be avoided : once a sentence is formed, it can be written down. A more difficult aspect of the problem is trying to disentangle that bit of coherency from everything else we're thinking about :

I took out the little pad provided by Hurlburt and jotted down this thought: “Deciding whether or not to buy a roll.” I know, not terribly exciting, but it seems very few of my mental contents are. I was thinking ahead to lunch and wordlessly deliberating whether to buy a fresh roll for a sandwich or do the responsible thing and use up the heel of bread I had at home. I was also conscious of the pattern of the skirt – an unflatteringly large plaid – worn by the woman standing in line ahead of me. 

Was that observation part of the moment in question, or did it come immediately before or after? I couldn’t say for sure. (How long does a moment in consciousness last ?) And what about the pervasive smells of freshly baked goods and cheese ? These both preceded and followed the moment under examination, but were they present to my awareness at the beep ?

Throw in just a few complications and suddenly the problem becomes much more difficult, maybe even impossible. Words ? We can attend to them. The whole facet of experience, including our different senses, how they affect us, when they occur, when we assemble a sentence ? That's much more fuzzy. Trying to describe anything before the point of coherency may even be a non sequitur. Maybe we can pin down a bit more about the process by determining what we're currently experiencing (e.g. which senses are given priority over the others, where and when we give out conscious attention to language rather than sensory experience, what counts as thought, etc.) but there will be some limits as to how far we can get with this.

Some really fascinating things have come out of the research though :

The first finding, to which I can personally attest, is just how little most of us know about the characteristics of our own inner experiences. “That’s probably the most important finding that I’ve got,” Hurlburt said.

Important, yes, but I think the other findings are a lot more interesting : 

Inner speech, which many of us – including many philosophers and neuroscientists – believe is the common currency of consciousness, may actually not be all that common. Hurlburt estimates that only a minority of us are “inner speakers”. So why do we think we talk to ourselves all the time? Perhaps because we have little choice but to resort to language when asked to express what we are thinking. As a result, we’re “likely to assume that’s the medium for inner thought”.

But that doesn’t make it true for everyone. Fewer than a quarter of the samples that Hurlburt has gathered report experiences of inner speech. A slightly lower percentage report either inner seeing, feeling, or sensory awareness. Still another fifth of his samples report experiences of “unsymbolised” thought – complete thoughts made up of neither words nor images. Hurlburt has suggested that we fail to recognise the diversity of thinking styles because we lump them all together under that single word – thinking – and assume we mean the same thing by it, though in actuality we don’t.

Aphantasia and the lack of inner speech is something I've covered many times before, but this is something beyond that. It's something I know I must have but am absolutely incapable of imagining. A truly pure thought consisting of... what, exactly ? Not language. Not any of the senses. Just pure electrochemistry, I guess. That's absolutely wild. 

EDIT : To a degree, I can imagine this. My inner monologue is pretty incessant, but it's not constant. There are times when it shuts up and all I have is sensory experience and emotions. What I absolutely cannot do is properly articulate what's going on. Is there still some processing going on using language at the lower levels, ready to be raised to my awareness for perusal when required ? Or is it fundamentally different at the earlier stages and only converted to language later on ? More below.

I wonder if the brain scans described in the BBC would be capable of interpreting these in the same way as for the (to me normal) case of thinking with an inner voice or eye. Perhaps it's like blindsight. That is, maybe our brains are all doing basically the same low-level stuff, but sometimes not everything is raised to whatever part it is that brings it to conscious awareness. Or maybe, even more interestingly, we don't all work in quite the same way. Regardless, scans of people who aren't thinking with inner speech, imagery, or any kind of structured thoughts would surely make for a fascinating comparison. Would the scan reveal the same thing as in those with well-defined internal monologues or would it show something else altogether ?

Another researcher suggests a different and more holistic approach :

The field’s focus on conscious perception has led it to overlook the 30-50% of mental experience that is fed to us by our minds rather than our senses, Kalina Christoff Hadjiilieva contends. “Consciousness is just one function of the mind,” Hadjiilieva told me during one of a half-​dozen interviews, this session over a cup of tea in my garden. “To focus on conscious thoughts is like focusing on the leaves of a tree and trying to understand them in isolation,” she said. “The tree is the mind, and there’s a lot more to the mind than consciousness.”

The degree to which the mind wanders appears to be surprisingly important :

Hadjiilieva conducted an experiment with long-​term meditators (mindfulness practitioners). These are people who have been trained to still their minds but also to notice the precise moment when that stillness is broken by an errant thought, which Hadjiilieva found happens every 10 to 20 seconds or so even in these trained minds. (“The big lesson of meditation,” she said, “is that the mind cannot be controlled.”)

This makes intuitive sense to me, and again maybe reveal something about the structure of thought processes. The way I like to work even, when in a state of relative focus, is often to flit back and forth between a couple of different things at once. I like to check my emails and glance at the news quite frequently, only going into really deep focus every once in a while*. WIth some tasks this works very well : it's like I have my brain keep working on the other thing in the background while giving my consciousness time to rest by attending to something easier. What's crucial for me, though, is that these must be activities of my own choosing. Being disturbed by an external influence is a big no-no, If someone interrupts me then the process is instantly broken.

* Though my work habits vary considerably. For code I nearly always concentrate on the code and absolutely nothing else, with a similar situation for most difficult problems. It's for the routine, less cognitively demanding tasks that I prefer to have multiple tabs open, as it were.

This all ties is quite nicely to the earlier discussion :

Hadjiilieva and her colleagues noted a jump in activity within the hippocampus, a key component of the default mode network that is involved in not only memory but also learning and spatial navigation. To their surprise, the leap in hippocampal activity preceded the arrival of the thought in the meditator’s consciousness by nearly four seconds – an epoch in brain time, and far longer than it takes for a sensory impression to cross the threshold of our awareness.

You might wonder if this further shifts my uncertainty about the apparent non-physical nature consciousness. In this case, it doesn't. I've already covered similar experiments regarding free will, and here it seems to me that no neural correlate could be anything remotely like subjective experience : how do some electrons whizzing about resemble the smell of a daffodil or the feeling of anger ? They simply don't, and to assume otherwise is to completely miss the point of the Hard Problem. But to build on from the previous post, this is still very interesting stuff : 

“Something is going on prior to awareness,” Christoff Hadjiilieva said, but she’s not sure exactly what it is or why it takes so long. This finding indicates that a spontaneous thought must undergo some sort of complicated unconscious processing before finding (or forcing) its way into the stream of consciousness. For Hadjiilieva, the mystery she’s uncovered points to what she regards as the “really hard problem of consciousness” – how the contents of the unconscious form into thoughts that sometimes find their way into our awareness, and sometimes don’t.

Well, that's definitely a hard problem, and maybe it would even be better to call it the hard problem. The Hard Problem of the philosophical sense may well turn out to be the Impossible Problem : we literally can't understand our own subjective experience, since by definition this is all we have access to. In that case some relabelling makes good sense. It seems very reasonable that the time delay points towards the brain doing some unconscious information processing before raising it to our awareness, and understanding how and why this happens seems extremely difficult but far from outright impossible.

The article concludes, in typical Guardian fashion, with a warning of the dangers of capitalism in preventing our minds from going about their productive, unguided wanderings, as well as the difficulties of persuading people to treat research into the subconscious as serious science. Perhaps the author should have read that BBC story. If you can access this with a machine, the danger may not be that nobody takes it seriously, but the exact opposite.

Review : Sentient (Part II)

Continuing a review/summary of Jackie Higgins Sentient. In part one I covered how biological senses are much more powerful than we might expect, even in us supposedly mediocre humans. In fact the basic sensory operations of many organisms appears comparable to the very best modern instrumentation. One photon of light, one atom of vibration, one molecule of a compound... the basic registration appears as good as can possibly be. The extraneous hardware - the shape of the nose, the ear, the size of the eye - that varies, but the fundamental conversion of the original signal into an electrical stimulus for the brain doesn't, or at least not much.

Animals do inhabit different sensory realities to ourselves though : that extraneous hardware makes a huge difference. A dog's nose being closer to the ground makes it far easier to access olfactory stimulation, and if its raw receiving power isn't that much greater than our own, its brain appears to be configured quite differently to deal with the signal. The great grey owl's face gives it far superior sound-collection powers, while the star-nosed mole's unique nasal protuberances allow for a sense of touch almost inconceivably different from our own.

Just how far does this go ? Here there is a slight weakness to Higgins book as she deliberately restricts herself to animal senses which humans are least partially share, so the electrical sense of sharks and the hydrodynamic sensing in fish don't get much of a look in. But as it turns out, there's some pretty compelling evidence that humans might share more animal senses than we usually assume. We think we all know about the basics of the eye and ear, but even these appear to have far more capabilities than our everyday experience. And as well as these familiar senses operating at a subconscious level, it also seems we might have other, wholly unfamiliar senses - without even realising it. 

In this second, concluding part, I'll look at some of those unconscious senses, beginning with the ordinary and progressing to the downright weird.

Sensing without sensation

Is it possible we have senses we're not aware of  ? To this the answer is a firm "yes". Blindsight is an intriguing one, but more ordinary examples include balance and proprioception (the sense of how our body is arranged - how we know where all our arms and legs are in the dark). Until these go wrong, we take them for granted. We don't have to think about which way is up, it is simply known. That knowledge is implicitly but not consciously filtered into our actions. 

It turns out there may be others as well. Some of these are more exotic than others, even verging on magical... which may go a long way to explaining why they've often been treated with extreme skepticism. Higgins notes many times when researchers, for a wide variety of reasons, have had great difficulty in persuading their peers that unconscious sensing is even possible.

Smell

Let's start with a return to the nose. In the previous section we looked at ordinary smells. More controversial are pheromones - scents which are "less chemical messenger than chemical command". In Dune, the Bene Gesserit use the Voice to cause override conscious objections : through the right tone of voice, tailored to the individual subject, Herbert posited that the conscious mind could be taken out of the loop, and so the Voice accesses direct, subconscious control. 

Pheromones, at least in animals, appear to be the nearest real-world equivalent. And they are incredibly potent. The giant peacock moth has more than three orders of magnitude fewer sensors than a dog's nose, but can detect female moth pheromones a thousand times fainter than anything a dog can pick up. How this equivalent millionfold increase in sensitivity is achieved is unknown.

I will take issue with a couple of claims in this chapter. First, that pheromones are such a more powerful command than other scents. That's as may be, but the giant peacock moth is not a good example - is it any wonder than an animal which lives only a few days, whose sole purpose is to reproduce, should react so strongly to a chemical stimulant advertising the availability of other sexy moths ? Higgins mentions pheromones in other animals, but never explains what the qualitative difference is. Second, that pheromones are perceived unconsciously - nowhere does she explain why researchers believe the effect is subconscious, why they don't think the animals perceive a smell they really like and react accordingly.

The point about pheromones overriding conscious control is not at all demonstrated for the case of humans either. And this is a problem, because such overstating the case has led to some ludicrous backlash. For example in one experiment trying to see if scent was a factor in human mate selection :

'Journalists got hold of the story and then politicians. One saw the words, "human, mate choice, genetics" in my proposal, tried to shut down the project and get me expelled. Then, she gave a nasty interview for an important local paper. Some of my volunteers read this and dropped out.' Other students started a protest. Newspapers quoted one who insisted the study was unsuitable because it 'optimised' offspring and another who claimed the study demeaned women by implying their 'functions and abilities are reduced to reproduction'. The furore grew. A politician denounced the project as 'Nazi research'...

All this for getting volunteers to smell some T-shirts ! But actually, nothing - nothing whatsoever - in the chapter implies that either gender is reduced to hapless sex-craved lunatics by a little sniff. It's about whether smell has an influence, not a matter of irresistible control. I cannot find anything in the chapter that justifies Higgin's description of pheromones are being qualitatively different in this regard from ordinary scents : sure, we all really like the smell of freshly-baked bread, but that doesn't send us spiralling into a whirlwind of self-destructive bread-based infatuation.

The point about smell causing an unconscious influence does seem on much more secure footing, however. Higgins cites the IgNobel*-winning study finding that strippers** received more tips when ovulating. In another case, heterosexual women and homosexual men were found to preferentially sit on a specially-dosed seat in a waiting room. Women rate men more attractive when they applied a certain compound, and when living in close proximity will synchronise their periods. Even babies react to the scent of their mother. And the T-shirt study which was eventually performed tuned out to have one of the most interesting results at all : mate selection seems influenced by complementary gene sets.

* The IgNobels are for research that first makes you laugh, then makes you think. They are not, despite the name and the often hilarious aspect, awarded because the research is bad or stupid.
** Sadly for the researchers they never had to interact with their subjects or even their environment.

In the main, these experiments are carefully done, repeated, and with multiple control conditions - Higgins is convincing in the claim that scent can have a subconscious influence. There's nothing here to me that says we're automatons with no free will, just that we don't act with 100% conscious control over 100% of our actions 100% of the time. From that perspective there's nothing new here. Far more interesting is that, like blindsight, our senses don't always interface directly with our mind. How does the brain decide what it is the mind needs to judge ? Why does it prefer to do some things consciously and some unconsciously ? And could we have other senses of which we're entirely unaware ?

Sound

Remember how the owl uses its entire face like a giant ear ? It seems that humans have more in common with this than you might think. Some blind people have trained themselves to make clicks and use the echoes to judge distances to nearby objects, but this is done through conscious training. Hearing also, however, provides subconscious information. Higgins recounts the tale of a man who went blind but began to develop a replacement faculty for his lost vision :

'In the quiet of an evening I had a sense of presence, which was the realisation of an obstacle. I discovered that if I stopped when I had this sense, and waved my white cane around, I would make contact with a tree trunk. I gradually realised I was developing some strange kind of perception. The experience is quite extraordinary, and I cannot compare it with anything else I have ever known. It is like a sense of physical pressure... upon the skin of the face.'

This so-called "facial vision" has been explored with controlled experiments, in which blind and sighted (but blindfolded) volunteers walked in a room until they thought they had reached the edge. While the blind people stop sooner, the sighted people also do not collide - unless, that is, they are also wearing headphones. In 400 such trials, not a single person failed to collide when deafened. And, when the headphones were not silent but connected to a microphone held by the volunteer, they regained their ability of collision-avoidance (which could be done to within an inch of the wall). It seems that hearing gives us much more information than we consciously realise, even if we don't have the capabilities of an owl or a bat - and there is real substance to the claim that blind people develop an improved sense of hearing.

Identity sentience

Before I get to the really whacky stuff, a few others deserve at least a brief mention. Rather than smell, the goliath catfish has adapted to have an extraordinary, full body sense of taste. More like our own sense of smell than taste, they can taste at a distance, in three dimensions, via taste buds distributed over their entire surface. Exactly how it experiences this is a mystery (though they appear to be able to sense pH levels), but in humans taste receptors are not just found on the tongue and lips : they're also found in the respiratory and digestive systems.

Unlike the taste cells in our tongue's papillae, the scattered taste cells never lead to any conscious bitter, salty, sweet or sour perceptions; they 'taste', but we do not. They work beneath our awareness... These bitter receptors do not create taste sensations, but prompt our body to eject airborne toxins or pathogens forcefully... 'No-one has defined what solitary chemosensory cells are in fish, let alone in humans. We don't know what these cells are doing. We don't even know what they mean.'

Might they help explain the sensation of an upset stomach, something not easily described by other sensory stimuli ?

I don't know. If taste senses are found throughout more of ourselves than is usually supposed, our sense of touch may be even more integral to our sense of identity. Higgins cites the rubber hand illusion as a demonstration, noting the complications of phantom limbs. The arguably related "senses" of pleasure and pain blur the lines further*, clearly related to direct sensory perception but not straightforward equivalents either. Like wavelength and colour, there is a connection, it's just very unclear what that connection is.

* This is in the chapter on the vampire bat, which is ill-constructed compared to the others. This is a shame, because there's a lot of interesting stuff here, like how they rely on food-sharing to survive and have heat sensors as well as echolocation. Unfortunately the chapter is too unfocused, never settling on a topic to drill down into the details, and lacking an overall structure to tie it all together.

Proprioception may be one of the strongest clues to a sense of identity. Here Higgins, I must say, does a better job of conveying what it's like to lose this sense than even the formidable Oliver Sacks. Both authors describe how patients learned to compensate with vision, able to send motor signals to their limbs but not receive the usual direct information about how they're positioned. Neither author is able to describe how this actually works usually - how exactly does the brain know about limb position ? Clearly we know this with a fine degree of precision; as I type this, my fingers flick back and forth over the keyboard without even needing to look at them. The brain does this with immense reliability and speed - how ?

Losing the sense is undeniably strange. Higgins describes a patient slowly (very slowly) learning to control himself as very much like the "wiggle your big toe" scene in Kill Bill 2. 

By staring at a limb, a digit, any joint, once again his brain was able to issue commands and move it. Vision and intention could stand in for his loss of proprioception. To this day, he remains utterly reliant on his eyes. If the light fails, he falls. If his focus falters for even the briefest of moments, he falls.

Higgins describes him as being both the puppeteer and the puppet. We are generally aware of "the aim, rather than the many acts required en route". Not so perhaps for the octopus, which might exist in a state not dissimilar from proprioceptionless-patients. Citing Peter Godfrey-Smith, it may generally leave its own limbs to get on with things independently most of the time, but the central brain has the ability to override and draw everything together when need be. 

Perhaps this isn't so different to the rest of us. As with blindsight, if your mind wanders, your limbs are fully capable of managing actions on their own... as Higgins says, you don't normally need to think about the minutiae*, but sometimes you don't even need to think about the aims. The number of times I've walked one door down the street from where I need to be, I couldn't tell you. It doesn't feel like I've lost my sense of identity though; we may all of us have a bit more in common with the octopus than we think.

* And when you do, what does this feel like ? Can you describe it ? I can't. It's some sort of irreducible knowledge, more than a mere sensation, that I'm in control of my actions : this is my will made manifest. 

Magnets

Okay, now we get into the more outlandish. We all know birds navigate in part by the Earth's magnetic field, but it seems some other animals can do this too. But how ? What does it feel like ? And if something as humble as a pigeon has this ability, why not people ?

Higgins describes at length the experiments to establish that birds do indeed navigate by the magnetic field, and moreover, this is disrupted by human electronics. Fortunately even going just outside a city is sufficient for these artificial fields to weaken so that birds can once again rely on their natural ability. Yet the sensitivity is, as with the other senses we saw last time, truly extreme : 

The bird compass can respond to forces that are one fifty thousandth [1 nanotesla] of the natural magnetic field... 'substantially below anything previously thought to be biophysically plausible. The bird's magnetic compass is a million times more sensitive than any other sensory system known.'

The debate over how exactly birds are able to register such changes is ongoing. There are two main theories, which is this case are not necessarily mutually exclusive. One is that it's from magnetite crystals found in the beak, a nice simple idea but potentially with problems explaining the extraordinarily high sensitivity levels. The other is a quantum theory which has no such difficulty, and potentially equips the birds with a whole new kind of vision :

Cryptochromes are found in the retinal rods and cones of a bird's eye. When a photon hits rhodopsin, its retinal molecule snaps into a different shape, setting in motion an act of sight; the quantum compass theory proposes that when a photon strikes a cryptochrome, it generates free radicals with mismatched pairs of electrons... their magnetic fields could interact with the Earth's magnetic field.

The objection from the magnetite camp is that this doesn't explain navigation in the dark, but we've seen that the eye can be sensitive to individual photons so this seems like a weak argument. Still, there's no reason birds might not use both systems. And, being in the eye, does the bird literally see the magnetic field, or perceive it in some other way ? Likewise, as to why it needs such extraordinarily high sensitivity levels, this is left unsaid. 

There's evidence that a host of other animals might use magnetic navigation as well : deer, turtles, eels, lobsters, snails, butterflies and mole rats. What about people ? We obviously can't "see" the magnetic fields in the way that birds (tentatively) might be able to, but could we be aware of it subconsciously ?

Evidence suggests... probably. Experiments taking blindfolded students on a long drive* found that they were remarkably accurate at pointing their way home, despite consciously stating that they have no idea where they were. But these had mixed results at best and replication was a problem, with even individual students giving highly variable results. Using EEG scanners with subjects in Faraday cages and sensory deprivation tanks* appears to be more promising, with changes in brain waves being induced in response to a magnetic field. More replication is needed, however, as is the need to find the sensor. But my impression is that the work which has been done so far is already so careful, so meticulous, that there is very likely something in it.

* And not murdering them at the end.
* The pro-magnetite crowd says this refutes the quantum vision theory, but it's not clear if these tanks really eliminate all photons, which is not such an easy task.

Most intriguingly of all, Higgins describes the case of the Guugu Yimithir aboriginal people of Australia, who demonstrate an ability similar but much superior to the blindfolded students. Another Australian tribe even lacks words for left and right, instead describing all directions in compass-style terms :

"They cannot explain how they know the cardinal directions, just as you cannot explain how you know where in front of you is and where left and right are. They simply feel where north, south, east and west are."

We've come across such abilities and people before. It's been suggested that is the language itself which bestows this magical ability, somehow granting us access to a whole other cognitive realm. This I have never found convincing. More plausibly, language is more a description of our (most fundamental) worldview rather than influencing the very basis of our perception. But that hasn't been a satisfactory explanation for how people could think in terms of absolute orientation - until now. I would not hitherto have speculated that humans could have an unsuspected magnetic sense.

I noted last time that this cardinal description of direction fades when people are sent from the flat terrain, where it usually develops, into somewhere more varied, but this is not at all mutually exclusive with the prospect that humans do also posses a magnetic sense. It might be dominant in flat, featureless deserts, and subsumed in more complex regions where landmarks are just a superior, easier method of navigation. Hence the language evolved in response to the particular circumstances : in this environment, humans are naturally far more in tune with this particular sense; it is the sense that causes the language, not the other way around. The only radical aspect would be the magnetic sense itself, with Higgins noting researchers face an uphill battle against the bias surrounding unconscious senses.

Time

Last but not least, how do we sense time itself ? Of all of physics, time seems one of the most mysterious of everyday realities. Some claim it's just an illusion created entirely by conscious perception, that it has no physical meaning in the way that space and mass do, while others hold that the forward progression of time is central to scientific understanding. Regardless, we clearly have an internal way of measuring time, however imperfect, so how does our internal clock actually work ?

The most obvious daily marker of time is the Sun, so experiments have revolved around depriving human and animal subjects of daylight. And indeed, orbweaver spiders show a natural rhythm independent of daylight - but it's not 24 hours, or even a multiple of 24. It can be anywhere from 18 to 28 hours, meaning that they live the life of the permanently jet-lagged. Why it isn't 24 hours, or at least something close to 24, is a mystery. But neat rhythms they naturally keep, regardless of sunshine, as do at least some plants.

As do also humans. Our body clock is set to 24-25 hours, which is a lot less weird (and makes a mockery of claims that humans could never adapt to the Martian 24.5 hour day). Yet, even when we can't see the Sun, it seems we can see time. 

Or rather more accurately : whatever process we use to sense the passage of time is present in our eyes. The Sun acts, if you like, to continuously set the hour hand, but the more frequent ticking is set by something in our eyes - provided we have incoming photons, whether from the Sun or no.

Experimental evidence of this comes from an unpleasant source. Postulating that vision had something to do with it, researchers engineered a mouse which had neither rods nor cones in its eyes. It was indeed blind. But it maintained a regular sleeping rhythm... until it was blindfolded. There is a third photoreceptor within the eyes, which has now been found and given the atrociously poor name of the "photosensitive retinal ganglion cell". Particular kinds of blindness in people have also been found to cause "time blindness".

How this actually works is a mystery. Could organisms be genetically encoded with some knowledge of the speed of light, such that something like a light clock could be present somewhere ? Nobody knows, though it would make sense that photons could be used for this just as they can be used for sensing magnetic fields. Nor, as far as I know, has anyone tried measuring the effects of complete, zero-photon darkness for protracted periods (elsewhere Higgins describes how this leads to hallucinations, so such extreme sensory deprivation might be fraught with ethical considerations). Certainly we don't literally "see" time. But that such a well-studied organ as the eye has such radical surprises in store for us only underscores the importance of further research, and how the nature of sentience itself is still an open question. Just what other senses might we have ?

Conclusions

Some of the bias against unconscious senses is understandable. The prospect that we could use photons to sense time and magnetic fields has more than a faint whiff of ESP and the like about it - if we can sense a global field which propagates at the speed of light, and given that birds have an apparently unnecessarily high degree of sensitivity, it's hard not to wonder if maybe this couldn't be used somehow for communication.

But this is unnecessary, and not warranted from the data. What's most compelling to me is that the mechanism for sensing the magnetic field relies on perfectly ordinary physics, and doesn't require the sensing process to be anything other than strictly one-way. That's not anything that even the most ardent skeptic should be worried about. Likewise, some of the bias against smell in particular is bizarre; to suppose that we are creatures of pure conscious choice is about as daft an idea as I've ever heard. No, because you subconsciously like the way someone smells does not make you a Nazi, you daft cultural warmonger. And I need to emphasise again just how careful and painstaking this research has all been, often a case of two steps forward one step back and then three more steps twirling sideways and falling over - establishing the magnetic sense in birds took seven years and more. The results are hard-won, rigorous science.

Still the question remains as to why these senses are subconscious. Especially interesting is that this occurs routinely in senses we also perceive consciously, like hearing (and on occasion vision). Why does the brain decide we don't need this information ? Why can't I get access to this normally, and just what else might the brain be doing in the background that it won't tell me ? That seems to open the door to those other, more radical sensory prospects.

As for language, as I've said many times, it is surely an interplay between deeper thought and expression. Even highly abstract, complex processes (like solving a differential equation) are done at some much deeper level within the brain, without the brain literally doing mathematics in the pen-and-paper symbolic sense. Yet when something is written down, that can trigger thoughts in new directions - the imperfection of language for recording and storing what we really mean is often a strength. So I think we can put safely to bed any notions that you need a language to really fundamentally alter our concepts of space and time, or give us new senses. It's still fascinating that we can use this to go in the other direction - to seek out cultures where, perhaps, our other hidden senses have risen to the top, shaping the way they express themselves.

Is one perception more valid than another ? This is hard to answer. Clearly some are more useful than others, but whether one is more "right" than another is altogether more challenging. Personally, I would welcome more sensory input. When the cyborg revolution begins in earnest, hook me up - let me hear those X-rays and smell the dark matter. I have no idea what this would be like, which is exactly why I'd want to do it.