Are the social sciences “real” science?

YouTube channel Crash Course is starting a new series on what is perhaps the most social of social sciences: Sociology.

The social sciences, such as sociology, but also psychology, economics, anthropology, and other similar fields get a lot of grief from people about not being “real” science.  This criticism is typically justified by noting that scientific theories are about making predictions, and the ability of the social sciences to make predictions seems far weaker than, say, particle physics.  Economists couldn’t predict when the Great Recession was coming, the argument goes, so it’s not a science.

But this ignores the fact that predictions are not always possible in the natural sciences either.  Physics is the hardest of hard sciences, but it’s married to astronomy, an observational science.  Astronomers can’t predict when the star Betelguese will go supernova.  But they still know a great deal about star life cycles, and can tell that Betelguese is in a stage where it could go any time in the next few million years.

Likewise biologists can’t predict when and how a virus will mutate.  They understand evolution well enough to know that they will mutate, but predicting what direction it will take is impossible.  Meteorologists can’t predict the precise path of a hurricane, even though they understand how hurricanes develop and what factors lead to the path they take.

The problem is that these are matters not directly testable in controlled experiments.  Which is exactly the problem with predicting what will happen in economies.  In all of these cases, controlled experiments, where the variables are isolated until the causal link is found, are impossible.  So scientists have little choice but to do careful observation and recording, and look for patterns in the data.

Just as an astronomer knows Betelguese will eventually go supernova, an economist knows that tightening the money supply will send contractionary pressures through the economy.  They can’t predict that the economy will definitely shrink if the money supply is tightened because other conflating variables might affect the outcome, but they know from decades of observation that economic growth will be slower than it otherwise would have been.  This is an important insight to have.

In the same manner, many of the patterns studied in the other social sciences don’t provide precise predictive power, but they still give valuable insights into what is happening.  And again, there are many cases in the natural sciences where this same situation exists.

Why then all the criticism of the social sciences?  I think the real reason is that the results of social science studies often have socially controversial conclusions.  Many people dislike these conclusions.  Often these people are social conservatives upset that studies don’t validate their cherished notions, such as traditionally held values.  But many liberals deny science just as vigorously when it violates their ideologies.

Not that everything is ideal in these fields.  I think anthropology ethnographers often get too close to their subject matter, living among the culture they’re studying for years at a time.  While this provides deep insights not available through other methods, it taints any conclusions with the researcher’s subjective viewpoint.  Often follow up studies don’t have the same findings.  This seems to make ethnographies, a valuable source of cultural information, more journalism than science.

And psychology has been experiencing a notorious replication crisis for the last several years, where previously accepted psychological effects are not being reproduced in follow up studies.  But the replication crisis was first recognized by people in the field, and the field as a whole appears to be gradually working out the issues.

When considering the replication crisis, it pays to remember the controversy over the last several years in theoretical physics.  Unable to test their theories, some theorists have called for those theories not to be held to the classic testing standard.  Many in the field are pushing back, and theoretical physics is also working through the issues.

In the end, science is always a difficult endeavor, even when controlled experiments are possible.  Looking at the world to see patterns, developing theories about those patterns, and then putting them to the test, facing possible failure, is always a hard enterprise.

It’s made more difficult when your subject matter have minds of their own with their own agendas, and can alter their behaviors when observed.  This puts the social sciences into what philosopher Alex Rosenberg calls an arms race, where science uncovers a particular pattern, people learn about it, alter their behavior based on their knowledge of it, and effectively change the pattern out from under the science.

But like all sciences, it still produces information we wouldn’t have otherwise had.  And as long as it’s based on careful rigorous observation, with theories subject to revision or refutation on those observations, I think it deserves the label “science”.

Posted in Science | Tagged , , , , | 41 Comments

What about subjective experience implies anything non-physical?

Mary’s room is a classic philosophical thought experiment about consciousness.  The Wikipedia article on what’s called the knowledge argument quotes Frank Jackson, the originator of the argument, as follows:

Mary is a brilliant scientist who is, for whatever reason, forced to investigate the world from a black and white room via a black and white television monitor. She specializes in the neurophysiology of vision and acquires, let us suppose, all the physical information there is to obtain about what goes on when we see ripe tomatoes, or the sky, and use terms like ‘red’, ‘blue’, and so on. She discovers, for example, just which wavelength combinations from the sky stimulate the retina, and exactly how this produces via the central nervous system the contraction of the vocal cords and expulsion of air from the lungs that results in the uttering of the sentence ‘The sky is blue’. […] What will happen when Mary is released from her black and white room or is given a color television monitor? Will she learn anything or not?

The takeaway idea from this thought experiment is supposed to be that, since Mary knows “all the physical information there is to obtain” about seeing color, what she learns when having her first actual sensory experience of color must be non-physical.

But this assumes that it is possible for Mary to actually know everything physical about seeing color, without actually ever seeing color.  It seems clear she does get new knowledge when she leaves the room, the knowledge of what it’s like to actually experience color.  The question is what the nature of that new knowledge is.  Like so many of these types of exercises, the premise essentially assumes the conclusion, that raw subjective experience isn’t physical.  But if the raw experience actually is physical, then the premise is a contradiction, positing that she has all the information, then going on to describe what information she doesn’t have.

But the question I have is, why does this premise, that experience is not physical, seem compelling to so many people?  (At a philosophical level.  I understand why so many people find it emotionally compelling.)

One of the chief features that separate humans from other animals is the degree to which we can think symbolically.  Language is the most common example of this ability.  Other animals issue sounds which mean something to those around them, such as a monkey who issues a certain screech for a snake, and a different screech for a flying predator.  But only humans appear able to manipulate the sounds in complex sentences and frameworks, particularly with hierarchical and recursive levels of complexity.

When we use language, we utter a sound that is a symbol for something else.  That something else might be another symbol acting as another placeholder for collections of more primitive symbols.  But eventually, if we follow through the hierarchy of symbols, the most primitive ones we can find will represent sensory perceptions, emotions, or actions, in other words, raw conscious experience.

Now, you might argue that some words refer to objects, such as dogs.  But dogs are themselves a composite sensory experience.  When I say the word “dog” to you, it evokes certain imagery.  But the dog concept generally denotes a certain type of animal with a certain type of body plan.  The imagery has colors, textures, shapes, sounds, and smells, in other words, more primitive sensory experiences.

We might also talk about the altered consciousness of meditative states some people experience.  But if you read descriptions of those states, they’re always either using a new word to label that state, or attempting to describe it in terms of the other primitives we’re all familiar with.

So, all language ultimately reduces to these primitive aspects of conscious experience: sensory perception, primal emotions, motor action, and perhaps meditative states.  Once we reach this point however, language ends.  While we can come up with words as stand-ins for these primitives, we can’t further describe them.

For example, consider trying to describe the color yellow to someone who had been born blind.  You can’t.  The best you can do is attempt to relate it into terms the blind person might understand, such as the feel of sunshine, the touch and smell of bananas, etc.  But you can’t describe the raw experience of yellow to them.  It’s ineffable.

But does this ineffability, this inability to subjectively reduce the raw experience further, mean anything about the reality of such an experience?  What about this ineffability might lead us to conclude it involves something other than physics?

It’s worth noting that just because these experiences can’t be subjectively reduced, it doesn’t mean that the neural correlates can’t be objectively reduced.  For example, we know the experience of yellow begins with photons with wavelengths of between 575 and 585 nanometers striking our retina, exciting a mixture of red sensitive and green sensitive light cone receptors and causing a cascade of electrochemical signals up the optic nerve to the thalamus and occipital lobe, somewhere producing what will eventually be communicated as yellow to the other brain centers.

Of course, we are far from a full accounting of the neuroscience here.  And many seem always ready to seize on the remaining gaps as an opportunity to wedge in mystical or magical notions.  But every year, those gaps close a little more.  Taking solace in them seems like an ever eroding stance.

A common argument is that we don’t know why these experiences exist.  Why can’t the brain go about its business without them?  This seems to assume that raw experience is superfluous to what the brain does, and perhaps that superfluousness means that it’s outside of the causal framework we call “physics”, an epiphenomenon.

But as I’ve noted before, the very fact that we can discuss primal experiences and apply symbolic labels to them means that they’re not outside of that causal framework.  It takes extreme logical contortions to avoid concluding they don’t influence at least the language centers of our brain.

So then, what explains experience?  As I’ve noted before, I think to have any hope of answering that question, we have to be willing to ask what experience actually is.  It seems like there are many possible answers, but the one I like best is grounded in the evolutionary reason for brains, to make movement decisions.  Experience is communication.  But communication from what to what?

I think the answer is: communication from the perception centers and emotion centers of the brain to the movement planning centers.  This communication provides information that is crucial for the movement planning centers to do their job.  What we call “experience” or “feeling” is the raw substance of that communication.  This communication includes sensory perceptions (including a sense of self) and emotional reactions.  Remove it, and it’s difficult to see how movement decisions can happen.

Of course, this remains a speculative explanation.  Any explanation of experience will be at this point.  The question is, does speculation of this type, built on physical functionality we already know has to exist in the brain, involve fewer assumptions than speculation about non-physical phenomena?

It’s often said that subjective experience can’t be explained physically.  My question is, what am I missing?  What about experience causes people to say this?  What specific attributes are outside the purview of any such explanation?

Posted in Mind and AI | Tagged , , , , , , , | 98 Comments

Kindle Oasis: a quick review

I read a lot of books, and as I’ve posted about before, the lion share of those books these days are Kindle e-books.

E-books aren’t for everyone, but for the last several years they’ve been my preferred way to consume a book.  I love the way I can buy a book and immediately start reading it, the fact that I can quickly search the book for specific words or phrases, that my large library of e-books is accessible from anywhere, and that it doesn’t take up any space in the house.  (A house that, despite an epic cleanup last  year, still has a lot of space taken up with shelves and mounds of traditional books.)

I started with a Kindle 2 in 2009, and after a year or so of tentative experimentation, pretty much went all digital.  After a while, I discovered the iOS Kindle app and started reading on my phone and iPad.  Within a few months, I almost never used the old Kindle device and eventually retired it.

The nice thing about reading books on iOS devices (and occasionally Android ones) was that I could see the color version of the book cover and the user interface was much more responsive.  But it’s always had a couple of drawbacks: an unreadable display outside in the sun and eyestrain caused by the screen backlight.  Seeing my phone screen in the sun is frequently an issue although I rarely attempt to read books outside, but the eyestrain thing has been an issue from time to time.  I’ve always handled it by minimizing the screen brightness and taking frequent breaks.

But given the improvement I’ve seen in my friends’ new Kindle Paperwhite devices, I decided it was time to try a dedicated Kindle again.  And as a voracious reader, I felt justified in splurging for the top of the line model: the Kindle Oasis.  (In reality, the price of this model is in the neighborhood of what I paid for the old device years ago.)

kindleoasisclosedsmallkindleoasisopensmallMy first impression of this thing was how small it is.  It’s not much bigger than my iPhone 7 and seems to be just as light.  It’s definitely smaller and lighter than the iPad I often read on.  But its battery life is far longer.  The included cover comes with an additional battery, which Amazon promises will last for months.  (Although that promise is based on 30 minutes of reading a day.  Yeah right.  I might get a week or two out of it, but that will be a lot more than I get out of the phone or tablet.)

The user interface on these new models is much more responsive than what I recall from my old one.  It’s still not as responsive as iOS devices, but then it costs a lot less, so pluses and minuses.  And the display is much sharper and clearer than the old model.  It really does look like printed text.  With the backlight off (it’s only needed in the dark), I was able to read from the device for hours with no more eyestrain than I would have gotten from reading a paper book.  For reading straight text, it’s working like a charm.

The loss of color is still noticeable when perusing the book library or catalog, but the amount of time I spend doing that is fleeting compared to the time actually spent in the books themselves.  I’m still waiting to see how well this device does for books with diagrams and tables, an area where I think Kindle on all devices has struggled somewhat, sometimes due to shoddy formatting from the publisher, but often simply due to limitations in the platform.

So, all in all, I’m pretty happy with it after a week of usage.  I had told a couple of friends I was picking one up, and they wanted to know my impressions, hence this post.  I’m definitely not going to stop reading on my phone when waiting for an appointment or in the grocery check-out line, and the iPad or laptop may still get some action for books with lots of tables and illustrations, but the Oasis seems poised to get the lion share of my home reading.

Posted in Zeitgeist | Tagged , , , | 10 Comments

Recommendation: The Stars Are Legion

thestarsarelegioncoverOccasionally on this blog, when pondering the far future, I’ve pushed back on the idea that the long term fate of civilization is to be machine robotic type life, instead noting that a truly advanced civilization would instead be engineered life, that it would make a lot more sense for its “machines” to be biological systems.  Admittedly, at some point, the distinction between engineered biology and very advanced machinery starts to become blurred.

Kameron Hurley’s ‘The Stars Are Legion‘ appears to take this idea very much to heart.  From one point of view, this is a classic sci-fi tale of an interstellar generation ship where things have deteriorated and everyone has forgotten the original purpose of the voyage.  But in this tale, the interstellar ark appears to be an artificial miniature solar system, with a miniature sun in the center orbited by innumerable world ships, all of which are called “the Legion”, with each world ship a living entity with its own homeostasis system.

The story characters live in these world ships.   They have the ability to travel between them on sentient single person rider ships.  Naturally, there is warfare between the worlds, with certain worlds conquering others and raiding their resources.  Things are not well in the Legion.  Many, perhaps most worlds appear to be dying, rotting.  The warfare is often about extracting resources to survive.

The interiors of the world ships are very strange; being biological systems, they are…gooey, with spongy walls and floor absorbing any spilled liquids (including blood), large arteries and veins running through the structures, and many other hallmarks of a living organism, such as the rooms coming across more like organelle compartments than traditional rooms.

Just about everything in this story is gooey, including the spray-on spacesuits.  And the characters often have a comfort level with the integrated biology of their environment that will leave many readers queasy.

But the strangeness doesn’t end there.  It quickly becomes apparent that the characters in the book are all female.  No males are mentioned.  Although as the story continues, it also becomes evident that the engineered biology doesn’t stop with the environment, but also applies to the characters themselves, and everything is not how it seems.

The story here is more than just an exploration of engineered biology.  It’s a searing story of two characters working to save their world, with these characters providing the two narrative viewpoints.  Here, Hurley takes a technique used in George R.R. Martin’s Song of Ice and Fire series and James S.A. Corey’s Expanse books, with each chapter named for that chapter’s viewpoint character.  But it’s taken to a new level with the viewpoints both being first person and in present tense, providing an intimate and immediate feel to the writing.

Shifting viewpoints is something that has historically happened in third person accounts, but it’s fairly rare in first person books, mainly due, I think, to the fact that it can be very easy to get confused about whose viewpoint we’re getting at any one point.  (Although there has been a trend in recent years pairing one first person protagonist with other third person narratives.)  But here we have two first person accounts.  It works because of the chapter title trick telling us upfront whose viewpoint we’re getting.  It’s a technique that I’m wondering if we’ll see more of.

Hurley’s world in this book is gooey, gory, violent, and often surreal.  In many ways, it reminds me of early Orson Scott Card stories from the 1980s.  I found it mind bending in ways that few books manage to pull off.  If you’re looking for something bizarre and thought provoking, and can tolerate violence and a lot of fairly gross description, I highly recommend it.

Posted in Science Fiction | Tagged , , | 22 Comments

What do scientific theories actually tell us about the world?

One of the things that’s exciting about learning new things, is that often a new understanding in one area sheds light on what might seem like a completely separate topic.  For me, information about how the brain works appears to have shed new light on a question in the philosophy of of science, where there has long been a debate about the epistemic nature of scientific theories.

Spacetime lattice Image credit: mysid via Wikipedia

Spacetime lattice
Image credit: mysid via Wikipedia

One camp holds that scientific theories reflect reality, at least to some level of approximation.  So when we talk about space being warped in general relativity, or the behavior of fermions and bosons, there is actually something “out there” that corresponds to those concepts.  There is something actually being warped, and there actually are tiny particles and/or waves that are being described in particle physics.  This camp is scientific realism.

The opposing camp believes that scientific theories are only frameworks we build to predict observations.  The stories we tell ourselves associated with those predictive frameworks may or may not correspond to any underlying reality.  All we can know is whether the theory successfully makes its predictions.  This camp is instrumentalism.

The vast majority of scientists are realists.  This makes sense when you consider the motivation needed to spend hours of  your life in a lab doing experiments, or to endure the discomforts and hazards of field work.  It’s pretty hard for geologists to visit the antarctic for samples, or for biologists to crawl through the mud for specimens, if they don’t see themselves in some way as being in pursuit of truth.

But the instrumentalists tend to point out all the successful scientific theories that could accurately predict observations, at least for a time, but were eventually shown to be wrong.

The prime example is Ptolemy’s ancient theory of the universe, a precise mathematical model of the Aristotelian view of geocentrism, the idea that the Earth is the center of the universe with everything revolving around it.    For centuries, Ptolemy’s model accurately predicted naked eye observations of the heavens.

But we know today that it is completely wrong.  As Copernicus pointed out in the 1500s, the Earth orbits around the sun.  Interestingly, many science historians have pointed out that Copernicus’ model actually wasn’t any better at making predictions than Ptolemy’s, at least until Galileo started making observations through a telescope.  Indeed, the first printing of Copernicus’ theory had a preface from someone, probably hoping to head off controversy, saying the ideas presented might only be a predictive framework unrelated to actual reality.

For a long time, I was agnostic between realism and instrumentalism.  Emotionally, scientific realism is hard to shake.  Without it, science seems little more than an endeavor to lay the groundwork for technology, for practical applications of its findings.  Many instrumentalists are happy to see it in that light.  A lot of instrumentalists tend to be philosophers, theologians, and others who may be less than thrilled with the implications of scientific findings.

However I do think it’s important for scientists, and anyone assessing scientific theories, to be able to put on the instrumentalist cap from time to time, to conservatively assess which parts of a theory are actually predictive, and which may just be speculative baggage.

But here’s the thing.  Often what we’re really talking about here is the difference between the raw mathematics of a theory, and its language description, including the metaphors and analogies we use to understand it.  The idea is that the mathematics might be right, but the rest wrong.

But the language part of a theory is a description of a mental understanding of what’s happening.  That understanding is a model we build in our brains, a neural firing pattern that may or may not be isomorphic with patterns in the world.  And as I’ve discussed in my consciousness posts, the model building mechanism evolved for an adaptive purpose: to make predictions.

In other words, the language description of a theory is itself a predictive model.  Its predictions may not be as precise as the mathematical portions, they may not be currently testable in the same manner as the mathematics (assuming those mathematics are actually testable; I’m looking at you string theorists), but it will still make predictions.

Using the Ptolemy example above, the language model did make predictions.  It’s just that many of its predictions couldn’t be tested until the availability of telescopes.  Once they could, the Ptolemy model quickly fell from favor.  (At least it was quick on historical time scales.  It wasn’t quick enough to avoid making Galileo’s final years miserable.)  As many have pointed out, it wasn’t that Copernicus’ model made precisely right predictions, but it was far less wrong than Ptolemy’s.

When you think about it, any mental model we hold makes predictions.  The predictions might not be testable, currently or ever, but they’re still there.  Even religious or metaphysical beliefs make predictions, such as whether we’ll wake up in an afterlife after we die.  They’re just predictions we may never be able to test in this world.

This means that the distinction between scientific realism and instrumentalism is an artificial one.  It’s really just a distinction between aspects of a theory that can be tested, and the currently untestable aspects.  Often the divide is between the mathematical portions and the language portions, but the only real difference there is that the mathematical predictions are precise, whereas the language ones are less precise, to varying degrees.

Of course, I’m basing this insight on a scientific theory about how the brain works.  If that theory eventually ends up failing in its predictions, it might have implications for the epistemic point I’m making here, for the revision to our model of scientific knowledge I think is warranted.

And idealists might note that I’m also making the assumption that brains exist, that along with the rest of the external world they aren’t an illusion.  I have to concede that’s true, and even if this understanding makes accurate useful predictions, within idealism, it still wouldn’t be mapping to actual reality.  But given that I’m also assuming that all you other minds exist out there, it’s a stipulation I’m comfortable with.

As always, it might be that I’m missing something.  If so, I hope you’ll set me straight in the comments.

Posted in Philosophy | Tagged , , , , , , , | 75 Comments

Arrival, the shape of aliens, and bridging the communication barrier

arrival_movie_posterThis weekend, I watched the movie ‘Arrival‘.  It starts off with the now common scenario of several floating ships appearing in the skies around the world.  But unlike most movies in this mold, it focuses on humanity’s efforts to communicate with the aliens and understand why they’ve come.  The protagonist is an expert in linguistics.

I found this movie to be uncommonly intelligent and high quality science fiction, of a type that we rarely see in cinema.  I’ve heard it’s won and been nominated for various awards.  In my opinion, it’s well deserved.  I highly recommend it.

That said, I’m going to quibble with a couple of its aspects.  I won’t spoil anything that you wouldn’t see in the first act, but if having even bits of that spoiled bothers you, you may want to skip this post until you’ve seen it.

I’m not going to quibble with the existence of the aliens, or why they arrived when they did.  A common criticism I have of alien invasion movies is that the aliens usually choose to show up when we can resist them, rather than any of the previous 4.54 billion years when the planet was a sitting duck.  But I actually think the movie has a good answer for that, which I won’t spoil.

Okay, first quibble.  The movie goes out of its way to portray the aliens as utterly, well, alien.  On the one hand, I very much appreciate this.  Too often, media sci-fi portray aliens as humans with maybe an extra bump on their forehead or in overall humanoid form but maybe with reptilian skin or something, together with all too human emotions and attitudes.  Historically, some of this came from technological constraints on what could be shown.  But with CG technology being what it is today, this excuse, still somewhat plausible for television, doesn’t really cut it for high production movies.

That said, in its attempt to make the aliens profoundly different, I think the movie ignores some simple realities.  Extraterrestrial life would undoubtedly be very different from Earth life, but the laws of physics put limits on just how strange it could be.

For example,we never see eyes on the aliens.  (Or at least I couldn’t ever make out any.)  Now, it’s possible that an alien that evolved in a consistently dark or opaque environment, such as an underground sea or in a thick opaque atmosphere, might never evolve vision.

But we see the aliens communicating visually, which implies some kind of ability to take in information from electromagnetic radiation (light).  And eyes weren’t a one time mutation in Earth history.  From what I’ve read, they evolved several times in independent evolutionary lines.  In other words, eyes are one of the features that evolution tends to converge on.  The aliens didn’t have to be portrayed with two stereoscopic eyes.  They could have had many, like on spiders.

The other is the overall body plan of the aliens.  They don’t come across as having much dexterity.  But as I’ve noted before, the only civilization producing species on this planet needed more than intelligence, but also the ability to physically manipulate the environment.  It’s why a primate species currently rules the planet instead of a cetacean, elephantine, corvine, or other type of intelligent species.

I’m not saying that the aliens needed to have humanoid body plans.  Ant-like bodies with prehensile limbs might have done the trick.  But the movie aliens needed to have better physical abilities than what was portrayed.  Their portrayed bodies might have been dexterous in a liquid environment, similar to cephalopods, but that didn’t appear to be the environment they were in.

My second quibble is with the effort to communicate with the aliens.  If you’ve seen the movie,  you understand this issue’s place in the plot, but the initial decision to translate written language doesn’t make that much sense.  As Seth Shostak of SETI (Search for Extraterrestrial Intelligence) has pointed out, it makes a lot more sense to attempt initial communication with pictures.

This makes sense when you consider that the earliest human writing evolved from using pictures to convey concepts.  Over time, the pictures got streamlined into symbols for each word or concept.  It was thousands of years before the idea of letters standing in for individual speech sounds developed.  Attempting to jump over all that with an utterly alien mind seems like the hard way to do it.

Of course, conveying complex information with pictures wouldn’t itself be easy.  For example, how do you get across the main question the humans had for the aliens, “Why have you come?”  But a series of pictures showing the alien ships approaching humans, followed by alternating pictures of humans dead or alive might have given the aliens a quick chance to make their intentions clearer.  And once you had a basic form of communication going, a common symbolic vocabulary could be worked out, eventually allowing more sophisticated exchanges.

A much tougher challenge might be if the aliens didn’t have visual senses.  Imagine trying to build a common vocabulary with a bat like alien that sensed the world through echolocation, or one that thought and moved on vastly different time scales, such as conscious trees.  But even then, we’d still live in the same universe, and there would have to be some common overlapping ways of perceiving the world.  It might come down to small model statues arranged in sequences to convey scenarios.

Of course, it’s always possible to engage in rationalizations to explain away these quibbles with the movie.  And as I indicated above, this is a movie that is far more intelligent than your typical sci-fi film.  Not the least because it gave me an excuse to talk about alien body plans and communication strategies 🙂

Posted in Science Fiction | Tagged , , , , , , , , | 40 Comments

Split brain does not lead to split consciousness – University of Amsterdam

I’ve talked before about Roger Perry’s famous split-brain patient experiments.  Patients with severe epileptic seizures used to undergo a collosotomy, a procedure to cut the connections between the left and right hemispheres of their cerebrum.  It often helped alleviate their symptoms and, remarkably, the patients afterward remained mentally functional, at least to outside appearances.

Each hemisphere of the brain controls and receives sensory input from half the body.  What Perry and his colleagues discovered in their experiments, was that if sensory inputs going into the patient were isolated to one hemisphere or the other, each of the patient’s hemispheres were only aware of its own sensations, and with the language centers usually focused on the left hemisphere, the patient could usually only describe what they were seeing when the left hemisphere received it.

The fact that the patients, post-procedure, remained largely functional seemed to show that each hemisphere was effectively watching what the other half of the body did, and mentally confabulating the actions as its own.  It opened up the possibility that this happens even in healthy people, albeit to a lesser extent.

However, new research appears to show that this phenomenon may be more limited than previously thought:



A new research study contradicts the established view that so-called split-brain patients have a split consciousness. Instead, the researchers behind the study, led by UvA psychologist Yair Pinto, have found strong evidence showing that despite being characterised by little to no communication between the right and left brain hemispheres, split brain does not cause two independent conscious perceivers in one brain. Their results are published in the latest edition of the journal Brain.

Source: Split brain does not lead to split consciousness

Assuming there are not any methodological issues with these new experiments (always a possibility), and given everything I’ve learned about the brain since first reading about the split brain patient experiments, I can’t say I find this too surprising.

The corpus collosum connects the cerebral hemispheres of the brain, but there are other regions which connect the two sides of the brain, mostly sub-cortical.  These areas are generally below the level of consciousness, but the information from them feeds into the cerebrum.

These results are also consistent with the phenomenon of blindsight, where a patient that has sustained damage to visual processing centers in the occipital lobe (part of the cerebrum) cannot consciously see  something, but if pressed, can often still identify it.  The reason for this is that while the optic nerve does feed into the cerebrum, it also branches off to sub-cortical regions such as the superior colliculus in the mid-brain region.  Again, the processing in those regions is below the level of consciousness (at least in humans), but it provides information, to a limited degree, to conscious regions.

It seems likely that, for the patients in the lower row of the image above, something similar is taking place.  Each hemisphere may not be able to consciously perceive what the other hemisphere is seeing, but communication in sub-cortical regions is bubbling up into the cerebrum, enabling them to make the determinations that they’re making in the new experiments.  Maybe.

But I’m not sure this necessarily justifies saying that the patient retains one unified consciousness.  It may be that it is less divided than previously thought, but definitely is more separate than the consciousness of healthy people.  Of course, I’m basing these remarks on the press release.  The actual paper may shed additional light.

I definitely plan to watch for any new developments in this area.  Or for any comments from Michael Gazzaniga, one of Perry’s assistants who are still around and writing.

Posted in Zeitgeist | 6 Comments