An Interview with Mark Changizi: The Vision Reveolution

MARK CHANGIZI is a theoretical neurobiologist aiming to grasp the ultimate foundations underlying why we think, feel and see as we do. His research focuses on “why” questions, and he has made important discoveries such as on why we see in color, why we see illusions, why we have forward-facing eyes, why the brain is structured as it is, why animals have as many limbs and fingers as they do, why the dictionary is organized as it is, why fingers get pruney when wet, and how we acquired writing, language and music.

He attended the Thomas Jefferson High School for Science and Technology, and then went on to the University of Virginia for a degree in physics and mathematics, and to the University of Maryland for a PhD in math. In 2002 he won a prestigious Sloan-Swartz Fellowship in Theoretical Neurobiology at Caltech, and in 2007 he became an assistant professor in the Department of Cognitive Science at Rensselaer Polytechnic Institute. [/mks_one_half]


In 2010 he took the post of Director of Human Cognition at a new research institute called 2ai Labs. He has more than three dozen scientific journal articles, some of which have been covered in news venues such as the New York Times, Wall Street Journal, Newsweek and WIRED. He has written three books, THE BRAIN FROM 25,000 FEET (Kluwer 2003), THE VISION REVOLUTION (Benbella 2009) and HARNESSED: How Language and Music Mimicked Nature and Transformed Ape to Man (Benbella 2011). He is working on his fourth non-fiction book, this one on emotions and facial expressions, called FORCE OF EMOTIONS. He is simultaneously working on his first novel, called HUMAN 3.0.




[mks_pullquote align=”left” width=”600″ size=”24″ bg_color=”#000000″ txt_color=”#ffffff”]Back in 2009 I had an Interview with Mark Changizi and Jam-e-Jam daily Newspaper published it. His works are amazing and also his books are deep and fascinating. So I re posted that Interview here too. [/mks_pullquote]




Pouria Nazemi   Cognitive science is a new science that we hear more about every day.   Can you briefly describe what it is? 

 Mark Changizi : Cognitive Science likes to define itself at the intersection of many disciplines, including psychology, neuroscience, linguistics, philosophy and computer science. But, in reality, you’d be hard pressed to pin us down. …other than to say that we’re all interested in understanding the principles underlying thinking, seeing, and other complex brain powers.

Pouria Nazemi  The brain is an amazing thing. We understand the world around us using it but how much do we know about brain itself?

Mark Changizi : Not much – in fact, I wrote a recent blog story titled “We don’t know jack” (Does that translate well?!). There are many avenues for being pessimistic about what we know – or don’t know – about the brain, but one that I often focus on is our powers, or functions. If some alien stumbled upon a calculator or a stapler, would you say that the alien understood these artifacts if the alien did not know that calculators are for math and staplers are for binding paper together? The aliens can take apart, catalog, and watch the workings of calculators and staplers for eternity, and if they haven’t figured out their function, we will be confident they haven’t come to understand them.

We’re in a similar situation as these aliens for our brains. We’ve had significant successes in taking apart the brain and watching its mechanistic workings, but the problem is that much of what our brain can do – most of the functions it is capable of carrying out – are simply not known by us. We’ll be in a good position to make sense of all our mushy meat only when we have a good idea about the functions the meat was selected to implement. And in order to do that, we have to study the human animal in a more ecological setting – that is, we must understand not just the brain, but the complexity of the environment for which it evolved, and how the brain (and body) fit the environment (often) like a glove. For example, my own research often focuses on showing that we have powers no one has noticed. You can be sure that if I’m finding new powers, then there must be tens of thousands more!

 Pouria Nazemi:   According to Scientific American : “Although many neuroscientists are trying to figure out how the brain works, Mark Changizi is bent on determining why it works that way”; so do you think we can learn why the brain works by having a better understanding of its structure?

 Mark Changizi : Another way of saying the same thing is that I want to reverse-engineer the brain. That’s what evolutionary types like me aim to do: figure out the principles governing our “design”.

Pouria Nazemi :   When I read about you I find that you have many interesting experiments and theory from writing systems to optical illusions and similarity of brain and highway systems. So what is the main goal of your research in these categories?
Mark Changizi : The research on writing systems asks why our brains, which do not have areas specialized for reading, can read so well. Could it be that the symbols and letters used in writing systems have culturally evolved over time to have the shapes our visual brains are innately good at processing? And, what is our visual brain good at processing? The shapes from nature, in particular from objects strewn about in a three-dimensional world. Could letters have come to look like nature, explaining why we’re such capable readers? In fact, that’s what I found: the contour conglomerations found in natural scenes tend to be the same ones found in human writing.
The brain and highway systems research comes from earlier work of mine trying to explain why brains change in the way they do from mouse to whale. My research shows that much of the anatomical changes that occur as brains increase in size (and there are a lot) can be explained by brains “trying” to maintain a fixed level of total-brain interconnectivity. It struck me more recently that cities have some similarities to the cortex: cities lie on the surface of the Earth and the cortex is a flattenable sheet; highways serve a similar role to white-matter-projecting neurons in the cortex; and highway exits a similar role to synapses. With my understanding of brain scaling in hand, I wondered the extent to which city highway systems scale similarly to the brain as a function of size. To my surprise, there were deep similarities in the scaling laws.
Another major research direction concerns color vision, where I have shown that our kind of color vision is nearly optimal for detecting oxygenation changes in blood under the skin. That is, I have been able to provide evidence that color vision is for seeing the emotions and other socio-sexual signals on the faces (and rumps) of others.
Is there anything tying my research together? Yes and no.
“Yes,” in that I tend to focus on “design principles,” i.e., on the fundamental engineering principles explaining why it would have evolved in the first place. I also bring a similar style to my research directions, aiming for broad unifying theories, ones that are rigorous, ones that can be tested, and ones where I can actually do test. (Rather than many physics journals, say, which publish biological theories without any data.)

 I want to reverse-engineer the brain. That’s what evolutionary types like me aim to do: figure out the principles governing our “design”.

But, “no,” in the sense that I do not try to build an incremental program of research. I have always actively tried to remain aloof from previous research problems, and from research communities, so that I am psychologically open to stumbling onto new ideas. Thus the crazy suite of research directions I am embarrassed to admit to.

 Pouria Nazemi  One of the most interesting things is your research about the brain’s ability to see into the future (1/10th second) so would you please explain more about that and if it is an ability we can hope to develop?

Mark Changizi: Well, you can’t actually see into the future. The point is that your brain has to anticipate a tenth of a second into the future – and generate a perception of it – because by the time it is done with its anticipating, a tenth of a second has elapsed, and so the anticipated future is of the present. That is, in order to at all times try to perceive the world as it is at that time – to “perceive the present” – the brain has to anticipate the near future.
My contribution here was to show how this simple idea is sufficiently rich that whole swathes of illusions can be explained as cases where the brain incorrectly anticipates the future.

 Pouria Nazemi : many of us enjoy optical illusions.  You are studying illusions as a way to understand how our brain works. I think illusions are the result of some error in our mind.  Would you please explain more about how these tricks tell us about our brain.

Mark Changizi: Let me explain one specific case, the Hering illusion shown below, where the two vertical lines are parallel but appear to bow out. Radial lines like those in the illusion do occur very often in real life, in particular whenever you move forward. At these times, the objects in the world flow outward in your visual field away from a center point. In fact, they even often blur on your retina, because your retina is not an infinitely fast “camera”. So, when you fixate on the illusion, your brain sees all those lines emanating from that center point, and says, “When I usually see this kind of radial blur stimulus, it is because I’m moving forward in the direction of the center point.” (I don’t actually mean your brain is saying this! I only mean it has evolved to have mechanisms that figure out where the observer is headed on the basis of blur cues like this.)

Now the brain has a good guess as to where it is headed. Recall that it takes about a tenth of a second to build a perception from the retinal stimulation. The brain wants to generate a perception of the two vertical lines not as they actually projected onto the retina, but as how they will project a tenth of a second later, after the observer has moved forward toward the center a little bit. Think about how the look of two vertical poles, or the sides of a doorway, change their shape as you move forward. When far away they appear vertical in your visual field. But as you near them, to pass between them, they flow outward in your visual field, but do so most quickly at eye level. To see this, imagine walking through a tall cathedral doorway, where when you are close, the upper parts of the door look like they are approaching one another up in the sky (like railroad tracks). That is, when you move forward through a doorway, the sides of the doorway bow outwards in your visual field, just like you perceive the vertical lines in the illusion. You perceive them that way because that is how they would project in the next moment were you moving in the direction your brain has been tricked into thinking it is going. Of course, it is being tricked in this case, so it counts as an illusion. But in real life it typically encounters such radial-line stimuli only when it actually is moving forward toward the center, as I mentioned above.

 Pouria Nazemi : Would you please explain about these categories of illusions?

Mark Changizi: The same explanation I just gave concerning the Hering illusion turns out to radically generalize. Radial lines are just one of seven cues I was able to identify for where the observer may be headed in the next moment. And it is not just the visual geometries that can distort in the next moment if you are moving forward; this is just one of four qualities that can distort in the next moment (the others concern speed, brightness contrast, and distances to objects). That is, I eventually realized that the explanation above extended to a 7 by 4 table of 28 predictions, the Hering-type classical geometrical illusions falling in just one of these 28 slots. And I provided evidence that the pattern of illusions predicted by this unified account was, in fact, the case.

 Pouria Nazemi Your recent well-received Book “The Vision Revolution” (that I didn’t have chance to get but would very much like to do) also is about our vision. Would you please tell us about the main focus of this book?

Mark Changizi: The book is about four “powers” of vision. Color vision is for sensing emotion, not for seeing fruit as it has been argued. Forward-facing eyes evolved for seeing better in cluttered forest environments, not for stereo-3D vision as it is usually argued. Illusions are the brain’s (failed) attempt at seeing the future…in order to perceive the present. And letter shapes have culturally evolved to look like nature, turning ancient illiterate visual areas in the brain into capable reading machines.

 Pouria Nazemi  We understand our world by our brains. There is nothing out there that we can understand without our brains. Also, we know that our brain sometimes (like in optical illusions) have misunderstandings. Is it possible that some parts of the world that we think we understand are really the result of such misunderstanding? I mean, how we can talk about reality if each brain is that object that determines what reality is?

Mark Changizi: Our brain was selected to provide perceptions that help us survive and reproduce, whether or not those perceptions actually gave us a more objective view of our real universe. The brain could, instead, give us perceptions that are “useful fictions” (which is the term people often use). However, very often the most useful perception to have is the one that actually does truthfully represent the world. As liars know, it takes a lot of work to string together lies in such a way that there are not contradictions. And often the best way to predict the world and not get eaten is to see the world as it is. So much of what we experience is veridical. But not all. For example, as I discuss in The Vision Revolution, color (colors are not out there), stereo vision (we see a single view from a perspective where we have no eye), and illusions (we see a guess) are all cases where useful fictions are at work.

 Pouria Nazemi :   Your new study show similarity between human brains and highway systems. How can man-made structures can be similar to our brain that evolved during millennia?

Mark Changizi: The idea is that, in each case, there is selection pressure shaping the organization. For the brain it is natural selection, which consists mostly of lots and lots of animals being eaten. For cities, although being eaten does sometimes make the news, the selection pressure is mostly due to multitudes of political and economic forces over many decades, which serve to slowly “push” a city to have a more efficiently functioning highway design.

 Pouria Nazemi : Is it possible that someday we can map our brains and understand completely how it works? And, if yes, how long will it take and what our the challenges along the way?

Mark Changizi: Yes. And I’d say hundreds of thousands of years, optimistically. Sorry for the pessimism. I mentioned some of the difficulties above. Another way to put things in context is to consider Caenorhabditis elegans, a little roundworm with 302 neurons, with about a thousand connections, and where we have nearly a “God’s eye view”. It is the most well understood organism on Earth, if not the universe. Despite everything we know about its details, we are a very long way from really understanding how the neural network relates to the complex sets of behaviors it carries out. (Probably because, I would say, we don’t completely understand its behavior.) Our brain has a wee bit more neurons than 302, and is the most complicated machine in the universe. We’re in for a long haul.

 Pouria Nazemi : If such a thing happens, everything would change because we could program brains to do many different things. Can you tell us more about the effects of such theoretical mapping in human life?

Mark Changizi: As for programming brains, I have actually thought about that. I wondered whether it may be possible to create images that provoke the visual system to carry out computations. Our visual system would be the hardware, the image would be the software, and the output of the hardware when run on the software would be our perception itself. Why not put our visual brain to work, making it do complicated calculations, and yet it wouldn’t feel like work to us, because all those visual computations are done unconsciously? So I created a class of stimuli called “visual circuits” that can do this, albeit not very well at this point. Here is a Wired story on the research…

 Pouria Nazemi : What is the next step in your studies?

Mark Changizi: For the last year or two I have been studying the origins of language and music. Like letters, I believe that the sounds of speech, and the sounds of music, culturally evolved to sound like nature. Too much to this story to get into here, but they will be the subject of my third book which I hope to finish by the end of the year: HARNESSED: How Language and Music Mimicked Nature and Transformed Ape to Man.

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