The Scientist on HARNESSED

“Changizi develops this simple but striking premise to show how language and music have been able to harness our brains,” by Richard P. Grant.

Jan 18, 2012: Telegraph

LEGO’s Missing Mojo

Roger Highfield discusses the troubling changes at LEGO over the years, and touches on my research on complexity and division of labor.

Jan 13, 2012: FRANCE

Our Brain’s Limits

Sabine Casalonga writes a gorgeous article on harnessing and the limits of human brains in Le Monde de l’intelligence. For more on how brains change with size see the links here.

Jan 6, 2012: WIRED

Biology’s Lego Laws

Samuel Arbesman discusses my research on the laws governing division of labor in bodies, brains, ant colonies, circuits, Legos and other networks.

Jan 5, 2012: AMSTERDAM

Art and Design

A piece by Sjoerd Tuinema about my art and design talk at the Museum of the Image.

Jan 5, 2012: REVIEW

Review of Harnessed

Julie Sedivy reviews my Harnessed among the “juicy” books of 2011, at Psychology Today.

Dec 23, 2011: BIG NEWS for HARNESSED!

Top Ten Science Book in 2011

I’m excited that my new book, Harnessed, is among New Scientist’s top ten science books of 2011, standing aside other authors I admire.

Dec 22, 2011: REVIEW

Review of Vision Revolution

Paul Harris reviews my Vision Revolution in the Journal of Behavioral Optometry.

Dec 21, 2011: CREATIVITY POST

Anglerfish and Creativity

Why I’m not a conference-goer. Lessons for creativity.

Dec 7, 2011: DISCOVER MAG, CRUX

Human Intelligence, Burst

Bursting the Bubble of Human Intelligence. What if the chasm between us and them is, instead, a slender fault line?

Dec 7, 2011: PAST BLAST

The Vision Revolutionary

My interview about The Vision Revolution at The Beautiful Brain with Noah Hutton.

Nov 16, 2011: DISCOVER MAG, CRUX

Later Terminator

We’re nowhere near artificial brains.

Nov 15, 2011: DISCOVER MAG, CRUX

What’s wrong with science ed

Engineers and scientists need different motivations. …and the role of Sagan.

Nov 2, 2011: REVIEW

Mind… Harnessed

“Generating controversial theories is not new to this evolutionary neurobiologist.” Frank Bures reviews Harnessed at Scientific American MIND.

Sep 30, 2011: WIRED

Gripping Grip

Move over gecko and tarantula. My new WIRED piece on pruney fingers.

Sep 14, 2011: FREAK

Rise of the Apes via Miracle Grow

Coincidentally, my book on the rise of the apes came out the same week as the movie, “Rise of the Planet of the Apes.” And, my book happens to be the only justification around for the movie premise. My guest piece at Freakonomics.

Sep 13, 2011: GET A GRIP

NY Times and Pruney Treads

In addition to the NYT picking up the pruney story, Jeremy Hsu covers it in Innovation News Daily. And also see Natalie Wolchover’s story in FOX News.

Sep 12, 2011: NOBEL

Nobel Reviews Harnessed

Nobel laureate Frank Wilczek took Harnessed home, “read it with fascination,” and reviewed it.

Sep 13, 2011: INTERVIEW

Salt Lake Tribune and Harnessed

My full interview with David Burger of the Salt Lake Tribune.

Sep 8, 2011: WEE WIRED

A Girl Becomes Self-Aware

GeekDad discovers Toy Story‘s terrifying developmental benefits.

Aug 31, 2011: UNCONVOLUTED

Getting a Grip, at Forbes

Can our pruney fingers help us build better rain treads?

Aug 25, 2011: REVIEW

Discover Mag, Harnessed

Review of HARNESSED in Discover Magazine, September, print.

Aug 25, 2011: PRESS RELEASE

HARNESSED Gets a Press Release

The press release for Harnessed.

Aug 22, 2011: REVIEWS OUT

Master of Distraction

My Wall Street Journal review of Cathy Davidson’s new book, NOW YOU SEE IT.

Aug 22, 2011: HUFF/AOL

Is Language Technology?

Is language a technology? Or, is it innate? Why my book, Harnessed, argues language (and writing and music) are technologies.

Aug 22, 2011: UK

New Scientist

The sounds of movement. New Scientist reviews HARNESSED, by Bob Holmes.

Aug 18, 2011: REVIEW

Forbes, Harnessed

David DiSalvo (author of What Makes Your Brain Happy and Why You Should Do the Opposite) writes about my new book.

Aug 18, 2011: SCIAM

Cities and Brains

Jason Goldman at Sciam on my research showing that cities are shaped like brains.

Aug 15, 2011: MUSIC

WNYC, Soundcheck

Music, harnessing, and me on WNYC radio.

Aug 15, 2011: CREATIVITY

Crazy-Ridiculous

What to do about all the crazy-ridiculous research?

Aug 9, 2011: HIJACKED

MSNBC’s CosmicLog

Nidhi Subbaraman interviews me about Harnessed.

Aug 8, 2011: INNOVATION

Our Future

Jeremy Hsu interviewed me about how “nature-harnessing” is the key to our future, as well as our present.

Aug 3, 2011: BRAIN PICKED

Maria Popova and HARNESSED

BrainPickings — one of the most influential sites on brain, culture and art — discusses HARNESSED.

July 30, 2011: EXCERPTED

Harnessing Scientific American

And excerpt from my book, HARNESSED, is now at Scientific American.

July 27, 2011: WIRED print

The Secret Sauce in Us

My WIRED UK print piece on how Homo sapiens became modern humans. …the topic of HARNESSED.

July 18, 2011: RADIO

Down Under

Phillip Adams of ABC Radio’s Late Night Live talks to me about the future of humans.

June 29, 2011: PRUNEY GRIP

Pruney rain treads

My new research: What pruney fingers are for. …rain treads. By myself, Romann Weber, Ritesh Kotecha and Joseph Palazzo.

June 15, 2011: BIG BRAINS

The Limits of Intelligence

The feature story in July’s print Scientific American, by Douglas Fox, on how big brains are made. …including my research on the issue. And here is his
podcast on the topic. More info. And see the connection to city organization (also here).

May 22, 2011: HARNESSED UNTAPPED

Wall Street Journal…harnessed

Music sounds like people, moving! The Wall Street Journal‘s Pia Catton interviews me about my new book on music (and speech).

May 21, 2011: TV on CHANGIZI

Dr. Kiki’s Science Hour

My video interview on Dr. Kiki’s Science Hour. I gab about my new book, Harnessed, and on what’s next, after humans. Also, I discuss what we’re doing at 2AI Labs. (Also viewable at Youtube.)

May 12, 2011: FORBES UNCONVOLUTED

The Path to the Brain

What should we unravel next, after the genome? Answer: The teleome, the complete set of an animal’s “powers.”

May 4, 2011: CHANGIZIFYING

Is Academia Eating Its Young?

Bill Benzon, author of Beethoven’s Anvil, on the trouble with academia. Blushing alert: “I take the case of Mark Changizi as an index of the current state of affairs. He’s one of the most brilliant and creative psychologists of his generation, but has chosen to abandon the academic ship because it didn’t give him room to think deep thoughts.” And here’s my
troubles-with-academia piece.

March 25, 2011: FORBES UNCONVOLUTED

3D Movies Could be So Much More

The trouble with “3D Movies” is that they’re not 3D movies so much as “binocular movies.”

February 23, 2011: HUMAN 3.0

Human Transformation, in Seed

My short “manifesto” of sorts about where we humans are headed, in Seed Magazine. (Hint: Not genes, not AI, not Borg.) Andrew Sullivan posts on my “manifesto” on what’s next, after humans. (He may follow my work, as he’s posted on earlier research on the origins of writing.)

~~~

All press stories on Changizi’s research.

~~~

Mark Changizi is Director of Human Cognition at 2AI, and the author of The Vision Revolution (Benbella Books, 2009) and the upcoming book Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man (Benbella Books, 2011). His first book was The Brain from 25000 Feet (Springer, 2003).

Samuel Arbesman discusses my research on biology’s Lego-laws at WIRED.

When complex systems are built, they’re built out of parts, and the parts come in multiple types.

For electronic circuits, any circuit can be built from a finite, universal set of component types. Does biology follow this “universal language” approach?

Well, no, as I discuss in this paper. And it turns out not even electronic circuits — as they exist in the real world, built by real companies — follow the universal-language approach.

And neither do Legos.

In both biology (networks of cells, neurons, or ants) and artifacts (networks of Legos, circuit components, or people), as the network gets larger, its division of labor increases (and as a power law).

But there are key differences as well that I discuss in the paper: Roughly, biological networks carry out their functions with more of their parts than human-created networks.

Samuel Arbesman, senior fellow at the Kauffman Foundation, has written a piece about this at WIRED.

~~~

Mark Changizi is Director of Human Cognition at 2AI, and the author of
Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man and The Vision Revolution. He is finishing up his new book, HUMAN, a novel about our human future.

New Scientist's Top Ten Science Books in 2011, Harnessed is on the right

I’m excited that my new book, Harnessed, is among New Scientist’s top ten science books of 2011, standing aside other authors I admire.

In the book I describe (and present a large battery of new evidence for) my radical new theory for how humans came to have language and music. They’re not instincts (i.e., we didn’t evolve them via natural selection), and they’re not something we merely learn. Instead, speech and music have themselves culturally evolved to fit us (not a new idea) by mimicking fundamental aspects of nature (my idea). Namely speech came to sound like physical events among solid objects, and music came to sound like humans moving and behaving in your midst (that’s why music is evocative). Each of these artifacts thereby came to harness an instinct we apes already possessed, namely auditory object-event recognition and auditory human-movement recognition mechanisms.

The story for how we came to have speech and music is, then, analogous to how we came to have writing, something we know we didn’t evolve. Writing, I’ve argued (in The Vision Revolution), culturally evolved to possess the signature shapes found in nature (and specifically in 3D scenes with opaque objects), and thereby harnessed our visual object-recognition system.

Buy the book here.

~~~

Mark Changizi is Director of Human Cognition at 2AI, and the author of
Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man and The Vision Revolution. He is finishing up his new book, HUMAN, a novel about our human future.

Many scientists believe that the human brain’s capacity for language is innate, that the brain is actually “hard-wired” for this higher-level functionality. But theoretical neurobiologist Changizi (director of human cognition, 2AI Labs; The Vision Revolution) brilliantly challenges this view, claiming that language (and music) are neither innate nor instinctual to the brain but evolved culturally to take advantage of what the most ancient aspect of our brain does best: process the sounds of nature. By “sounds of nature,” Changizi does not mean birds chirping or rain falling. His provocative theory is based on the identification of striking similarities between the phoneme level of language and the elemental auditory properties of solid objects and, in the case of music, similarities between the sounds of human movement and the basic elements of music.

Verdict: Although the book is written in a witty, informal style, the science underpinning this theoretical argument (acoustics, phonology, physics) could be somewhat intimidating to the nonspecialist. Still, it will certainly intrigue evolutionary biologists, linguists, and cultural anthropologists and is strongly recommended for libraries that have Changizi’s previous book.

~~~

Mark Changizi is Director of Human Cognition at 2AI, and the author of
Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man and The Vision Revolution.

Now, I’m not a fan of tit-for-tat responses to book reviews, so I’ll let you gauge Levitin’s arguments for yourself after reading my book.

But one casualty of his review is humor — or Levitin’s lack of recognition of it — and that I’ll correct here.

You see, in my book I boast, as Levitin tells us, “about classrooms of undergraduates standing in awe of” me.

What a start to a review! I’m painted as a boastful braggart on the first line of entry into ChangiziLand (“ChangiziLand” is where all my awe-filled followers live).

And, my god, it’s true! I indeed do say something along those lines! In fact, my own words now (p. 32):

“It can be difficult for students to attract my attention when I am lecturing. My occasional glances in their direction aren’t likely to notice a static arm raised in the standing-room-only lecture hall…”

What. An. Arse! …I’m referring to me.

Except– Wait. I wrote more.

“…and so they are reduced to jumping and gesturing wildly in the hope of catching my eye. And that’s why, whenever possible, I keep the house lights turned off.”

Well that’s peculiar. Are my students really “jumping and gesturing wildly”? Really? And do I actually turn the house lights off to prevent my having to view said wild gesturing?

Perhaps. Levitin doesn’t know me from Adam, so, uh, maybe that really happens in my lectures.

But here’s the fuller excerpt from that section…

It can be difficult for students to attract my attention when I am lecturing. My occasional glances in their direction aren’t likely to notice a static arm raised in the standing-room-only lecture hall, and so they are reduced to jumping and gesturing wildly in the hope of catching my eye. And that’s why, whenever possible, I keep the house lights turned off. There are, then, three reasons why my students have trouble visually signaling me: (i) they tend to be behind my head as I write on the chalkboard, (ii) many are occluded by other people, are listening from behind pillars, or are craning their necks out in the hallway, and (iii) they’re literally in the dark.

These three reasons are also the first ones that come to mind for why languages everywhere employ audition (with the secondary exceptions of writing and signed languages for the deaf) rather than vision. We cannot see behind us, through occlusions, or in the dark; but we can hear behind us, through occlusions, and in the dark. In situations where one or more of these — (i), (ii), and (iii) above — apply, vision fails, but audition is ideal. Between me and the students in my course lectures, all three of these conditions apply, and so vision is all but useless as a route to my attention. In such a scenario a student could develop a firsthand appreciation of the value of speech for orienting a listener. And if it weren’t for the fact that I wear headphones blasting Beethoven when I lecture, my students might actually learn this lesson.

And did you hear that last part? I jam to classical music during my lecturing so that I cannot possibly hear any questions from students. That’s just…impractical!

If it still wasn’t obvious that I was joking, several paragraphs further down I indicate — just for the barely-reading, I-already-think-Changizi-is-a-prick reader — that my earlier-mentioned gesticulating students are fictional.

~~~

Mark Changizi is God of Human Cognition at 2AI, and the author of most excellent books such as The Vision rEvolution and Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man.

One thing led to another, and Nobel laureate Frank Wilczek got hold of my book, “read it with fascination,” and gave it a review at Edge.

Herman Feshbach Professor of Physics, MIT; Recipient, Nobel Prize in Physics, 2004; Author, The Lightness of Being

Mark Changizi re-imagined the transition from ape to human. Physical aspects of that transition are documented in the fossil record, and in our DNA, but what about the mental aspects? How, specifically, did the abilities most characteristically “human”—speech, writing, music—get any traction? Here we face an evolutionary conundrum, for those abilities appear useless until they are fully developed (or even after, in the case of music), while evolution by natural selection must proceed by small steps, each contributing to fitness. Darwin himself worried, on similar grounds, over the emergence of sophisticated eyes; the linguists’ postulated organ of language poses, if anything, a knottier puzzle. Changizi proposes that human speech, writing, and music are grounded in much simpler natural abilities. His proposals are impressively specific: basic speech sounds derive from the sounds of impacts among solid bodies; the basic symbols of writing derive from recurring features of natural scenes; the basic elements of music are abstracted from the natural sounds accompanying human (or ape) movements. Biologically useful abilities to discriminate and interpret those features of the natural world evolved, through relatively small steps of abstraction, into our human toolbox. I took Changizi’s Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man — a freebie at Scifoo! — home, and read it with fascination. It describes many oddball facts about language and music that his ideas make sense of. I’d be amazed if everything he says is right; but at this point I’d be even more surprised if his main ideas, which crack open riddles that have annoyed me for years, aren’t on the right track.

~~~

Mark Changizi is Director of Human Cognition at 2AI, and the author of
Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man and The Vision Revolution.

The paper has, for a time, been given free access by the publisher.

News stories on our research have appeared widely, including Nature, NPR, MSNBC, Discovery, PBS News Hour, Gawker, NY Times, Washington Post, Innovation News Daily and FOX News. I also wrote a piece on it at Forbes.

Also… comics.

~~~

Mark Changizi is Director of Human Cognition at 2AI, and the author of The Vision Revolution (Benbella Books) and the upcoming book Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man (Benbella Books).

Or, at least, that’s what they say.

But there is at least one variety of curvy mathematics that your brain comprehends so completely that you don’t even know you know it. It concerns your visual field, and your innate understanding of the directions from you to all the objects in your environment.

In thinking about your visual field, it is best to imagine a sphere around your head, recording the directions to all objects in one’s environment. Call it the “projection sphere,” since it records in which directions objects project light toward us.

So, if you are standing in front of a row of six vertical poles, then they will project onto your sphere as shown below. In this figure, one imagines that you, the observer, are at the center of the sphere, looking in the direction of the cross.

Consider now the way these poles project…

First, notice that each pole appears straight in your visual field. They are not straight in the figure above, but remember that the observer in the figure is at the center of the sphere looking out. Each pole is straight on this projection sphere — and thus in your visual field — because each is what is called a “great circle,” extending in this case from the bottom to the top of the sphere like lines of longitude.

Second, observe that the poles are parallel to one another at the equator.

Yet, despite being straight lines that are parallel to one another, they intersect! Namely, the lines intersect at the top and bottom of the sphere.

Can this really be?

It can really be, and it is possible because of the non-Euclidean nature of the geometry of the visual field.   The geometry that is appropriate for the visual field is the surface of a projection sphere, and the surface of a sphere is not flat / Euclidean, but, well, spherical.

There are three main kinds of geometry for space: elliptical (including spherical), Euclidean (or flat), and hyperbolic.  How does one tell them apart? One way is to simply measure the sum of the angles in a square drawn in that space.

In Euclidean geometry, the sum of the angles in a square is 360 degrees. But for elliptical geometry the sum adds up to more than 360 degrees. In hyperbolic geometries, on the other hand, the sum comes to less than 360 degrees.  Back to the visual field, then, let’s “draw” a square on it and sum up its angles.

The figure above shows a square in your visual field. Why does it count as a square? Because (i) it has four sides, (ii) each side is a straight line (being part of a great circle), (iii) the lines are the same length, and (iv) the four angles are the same.

Although it is a square, notice that each of its angles is larger than 90 degrees, and thus the square has a sum of angles greater than 360 degrees.  The visual field is therefore elliptical, and spherical in particular.

One does not need to examine figures like those above to grasp this. If you are inside a rectangular room at this moment, look up at the ceiling. The ceiling projects toward you as a four-sided figure. Namely, you perceive its four edges to project as straight lines. Now, ask yourself what each of its projected angles is. Each of its angles projects toward you at greater than 90 degrees (a corner would only project as exactly 90 degrees if you stood directly under it).

Thus, you are perceiving a figure with four straight sides, and where the sum of the angles is greater than 360 degrees.

Your visual field conforms to an elliptical geometry!

(The perception I am referring to is your perception of the projection, not your perception of the objective properties. That is, you will also perceive the ceiling to objectively, or distally, be a rectangle, each angle having 90 degrees. Your perception of the objective properties of the ceiling is Euclidean.)

It is often said that non-Euclidean geometry, the kind needed to understand general relativity, is beyond our everyday experience, since we think of the world in a Euclidean manner. While we may think in a Euclidean manner for our perception of the objective lines and angles, our perception of projective properties — i.e., the directions from us to the world around us — is manifestly non-Euclidean, namely spherical.

We do have tremendous experience with non-Euclidean geometry, it is just that we have not consciously noticed it. But once one consciously notices it, it is possible to pay more attention to it, and one then sees examples of non-Euclidean geometry at every glance.

~~~

A view of "Plastic Animal Chess" in action, on a tile floor.

I just wrote a piece for Wired UK on creativity and child-like irreverence, and I talk about the game my daughter invented, a variant on chess. I had taken some photos, though, that did not make it into the story.

The first is this one here at the top, an animal-level view of the game in action on the tile floor of my sun room.

The second is below, my daughter’s hand-written rules themselves, with blanks where we filled in the animals used for each piece type.

My eight-year-old daughter's hand-written rules for plastic animal chess.

UPDATE: Wired has published a “Part 2″ to my daughter’s chesscapades… In this new piece, they write up my daughter’s hand-written rules, as well as put in some rules not quite in her rules, because she left a lot ambiguous. When she and I played, she chose a 5 by 17 tile stretch of the sun room, with the pieces at opposite ends. I’ll need to get her to remind me of the exact starting positions.

UPDATE: On the May 6, 2011, episode of ‘The Big Bang Theory’, they had a funny bit with Sheldon creating a radical new form of geeky chess. Could it be that they saw the story and it motivated their bit? Who knows? But, between you and me, I’m telling my little girl she’s responsible for the bit.

~~~

For more on irreverence and creativity, see irreverence and aloofness and… anglerfish.

~~~

Mark Changizi is Director of Human Cognition at 2AI, and the author of The Vision Revolution (Benbella Books, 2009) and the upcoming book Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man (Benbella Books, 2011). His first book was The Brain from 25000 Feet(Springer, 2003).

Getting these animals tipsy and stabbing them through the eye with a stake turns out to be much less impressive than when Odysseus did it.

For vertebrates we find no cyclopses. On some fish, frogs, lizards and relatives there is a third eye (a “parietal eye”) directly on the tops of their heads (middle photo below), which is cyclops-like in not being paired with another eye. However, although these eyes are light-sensitive, they are not really eyes at all because they are not capable of forming an image of the outside world. Instead, they seem to be involved in thermoregulation, although no one is quite sure.

The closest thing higher vertebrates have to cyclopses are anencephalic infants, like the kitten shown below. But that’s nature’s mistake.

One reason for the scarcity of cyclopses is that they can’t see what’s behind them.

Most of the Earth’s animals with vision, however, can see much of what’s behind them, and presumably need to.

They do this via having two eyes facing in opposite directions.

This is true, for example, of squid, insects, fish, reptiles, dinosaurs, birds, and many mammals like rabbits and horses (see photos below). You can’t sneak up on these animals from behind.

Let’s take notice of something so obvious about the animals pictured above that one is apt to overlook it.

These animals have eyes facing in opposite directions, as I mentioned, but more specifically their eyes are on the sides of their heads, so that the eyes point sideways, as in the drawing of the animal on the left, below.

But this is not the only possible way of having panoramic vision.

One could instead place a single eye on the very front of the head, and another on the very back, as illustrated below and on the right. You never find this in nature (and not even in fiction, as far as I know). Why not?

The reason has to do with the fact that those sideways-facing eyes earlier don’t just see the opposite sides of the animal.

Instead, they typically also have some overlap, i.e., parts of the world that both eyes can see, called the binocular region.

Seeing a part of the world via two eyes has certain advantages, advantages that animals typically want to bring to bear in front of themselves.

For animals with sideways-facing eyes, the binocular region does tend to be in front.

For example, for the drawing of the animal above and on the left, you are in its binocular field because you can tell that each of its eyes can see you.

For animals with an eye on the front of its head and another on the back, however, any overlapping regions of the visual field would be along the sides of the animal, not the front.

…and animals don’t tend to want their especially powerful vision directed to the sides.

Our vision is a variant of having eyes on the sides of the head in the sense that our eyes are placed on the left and right of our midline, and so our binocular region is also in front.

What are these advantages of binocular vision for seeing the world?

The typical answer that would be given by anyone knowing anything about vision will be stereo vision, or the ability to see in depth. The study of binocular vision is so historically wrapped up with stereo vision that courses and books about binocular vision tend to be largely about this special kind of depth perception.

Contrary to conventional wisdom, however, in my research I have come to appreciate a power of binocular vision no one has yet noticed: the power to see through stuff. As I discuss in my book,The Vision Revolution, understanding this “x-ray power” is crucial for understanding why we have forward-facing eyes.

But in this piece I want to point out a special, very fundamental, kind of “x-ray vision” binocular vision gives us, one that helps further drive home the advantages to panoramic vision via sideways-facing eyes rather than via front-and-back-facing eyes.

…It is the power to see through yourself.

Before an animal can worry about how to most ably see what’s out there in the world, it has to make sure it can actually see what’s out there. A fancy eyeball placed on the inside roof of its mouth would not see much of the world.

But where should you put the eyes?

Most spots will be better than the roof of the mouth, but bodies tend to have gangly parts that could possibly block an eye’s view.

And, in fact, one typically wants some of those body parts to be out in front of the eye, body parts like a mouth, nose, whiskers or hands that are designed to physically interact with the things out in front. Animals want these appendages out in front of the eye not only because these appendages are good at touching the world and eyes are not, but also because it is useful to see one’s own appendages so as to help guide the appendages’ interactions with the world.

And that leads to a riddle that animals with vision had to solve.

Namely, how can they put appendages out in front of their eyes, yet not occlude their view of the world?

This is a riddle that video game makers have had to grapple with as well. How do you let the player see his own character without obstructing the view of the game?

If you play games in first-person perspective mode, then if your character is holding a gun or sword, its arm and weapon occlude a significant portion of the screen (see the upper image below).

If you play in third-person perspective mode—where you see the entire character from behind—then there are also significant parts of the view missing due to the character’s whole body blocking the view (see the lower image below).

That’s why many games allow the player’s viewpoint to roam around the character — rather than being locked with a view of the character’s back. Allowing our eyes to float steady-cam style around our bodies and relay information to our brains would, then, be a potential solution to the problem of seeing past our own appendages.

Nature found a different solution, however, and you can see it for yourself by looking at your own nose.

If you close one eye and wiggle your nose, you’ll see it in the bottom corner, blocking that eye’s view of whatever’s beyond it, as illustrated in the pair of upper images in the figure below.

But, if you now open the other eye you’ll see what’s behind your nose via this other eye (illustrated by the lower image below).

In fact, you’ll perceive your nose still to be there, but perceive it to be transparent through which you are seeing the scene beyond.  Each eye sees the nose, and each has its view blocked by the nose. But the views blocked by the nose are different for each eye, so the pair of eyes, in total, don’t miss a thing. …and yet can also see your nose.

If, instead, an animal’s eyes were on the front and back of its head, then the appendages out in front of the front eye would simply occlude its view.

Having eyes on the sides of the head (or on either side of the midline, like ours) rather than on the front and back is not only, then, useful for placing the powerful binocular region in front of the animal for the purpose of better perception of what’s out there.

In addition, having eyes on the sides of the head is crucial for seeing past one’s own bodily appendages.

And not just seeing past one’s own appendages, but simultaneously seeing them and thereby having the advantages that come with having this visual feedback.

See through oneself may be one of the most fundamental reasons why animals have eyes on either side of their head and possess a binocular region.

~~~~

This was adapted from Chapter 2 of The Vision Revolution (Benbella, 2009).

~~~

Mark Changizi is Director of Human Cognition at 2AI, and the author of The Vision Revolution (Benbella Books, 2009) and the upcoming book Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man (Benbella Books, 2011). His first book was The Brain from 25000 Feet (Springer, 2003).