Feeds:
Posts
Comments

Posts Tagged ‘binocular vision’

Jorge Salazar of EarthSky.org recently interviewed me about my research, and you can find the podcast and text here. I got a chance to talk about the similarity between accents and color vision (how we all believe we have uncolorey skin and no accent), the function of color vision (it’s for giving you that empath sense you didn’t know you have), and why we don’t have eyes on the sides of our heads (it’s for seeing better in cluttered leafy habitats, just the thing for a primate).

~~~

Mark Changizi is Professor 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).


Advertisements

Read Full Post »

Ian Woolf of Diffusion Radio just reviewed The Vision Revolution, and you can hear the podcast here (15 minutes in).

=============

Mark Changizi is a professor of cognitive science at Rensselaer Polytechnic Institute, and the author of The Vision Revolution (Benbella Books).

Read Full Post »

Recently I was interviewed Jovana Grbic of ScriptPhD about The Vision Revolution. She has a great knack for asking unusual questions, taking me out of my standard responses and making me think. (To find the podcast itself, scroll down within this link until you see it.) I also wrote a guest piece for them on idea-mongering and non-genius that you’ll find there.

=============

Mark Changizi is a professor of cognitive science at Rensselaer Polytechnic Institute, and the author of The Vision Revolution (Benbella Books).

Read Full Post »

This first appeared on January 2, 2010, as a feature at the Telegraph.

You know what I love about going to see plays or musicals at the theater? Sure, the dialog can be hilarious or touching, the songs a hoot, the action and suspense thrilling. But I go for another reason: the 3D stereo experience. Long before movies were shot and viewed in 3D, people were putting on real live performances, which have the benefit of a 3D experience for all the two-eyeds watching. And theater performances don’t simply approximate the 3D experience – they are the genuine article.

“But,” you might respond, “One goes to the theater for the dance, the dialog, the humans – for the art. No one goes to live performances for the ‘3D feel’! What kind of low-brow rube are you? And, at any rate, most audiences sit too far away to get much of a stereo 3D effect.”

“Ah,” I respond, “but that’s why I sit right up front, or go to very small theater houses. I just love that 3D popping out feeling, I tell ya!”

At this point you walk out, muttering something about the gene pool. And you’d be right. That would be a rube-like thing for me to say. We see in 3D all the time. I just saw the waitress here at the coffee shop walk by. Wow, she was in 3D! Now I’m looking at my coffee, and my mug’s handle appears directed toward me.Woah, its in 3D! And the pen I’m writing with. 3D!

No. We don’t go to the live theater for the 3D experience. We get plenty of 3D thrown at us every waking moment. But this leaves us with a mystery. Why do people like 3D movies? If people are all 3D-ed out in their regular lives, why do we jump at the chance to wear funny glasses at the movie house to see Avatar? Part of the attraction surely is that movies can show us places we’ve never been, whether real or imaginary, and so with 3D we can more fully experience what it is like to have a Tyrannosaurus Rex make a snout-reaching grab for us.

But there is more to it. Even when the movie is showing everyday things, there is considerable extra excitement when it is in 3D. Watching a live performance in a tiny theater is still not the same as watching a “3D movie” version of that same performance. But what is the difference?

Have you ever been to one of those shows where actors come out into the audience? Specific audience members are sometimes targeted, or maybe even pulled up on stage. In such circumstances, if you’re not the person the actors target, you might find yourself thinking, “Oh, that person is having a blast!” If you’re the shy type, however, you might be thinking, “Thank God they didn’t target me because I’d have been terrified!” If you are the target, then whether you liked it or not, your experience of the evening’s performance will be very different from that of everyone else in the audience. The show reached out into your space and grabbed you. While everyone else merely watched the show, you were part of it.

The key to understanding the “3D movie” experience can be found in these targets. 3D movies differ from their real-life versions because everyone in the audience is a target, and all at the same time. This is simply because the 3D technology (sending up left and right eye images to the screen, with glasses designed to let each eye see only the image intended for it) gives everyone in the audience the same 3D effect. If the dragon’s flames appear to me to nearly singe my hair but spare everyone else’s, your experience at the other side of the theater is that the dragon’s flames nearly singe your hair and spare everyone else’s, including mine. If I experience a golf ball shooting over the audience to my left, then the audience to my left also experiences the golf ball going over their left. 3D movies put on a show that is inextricably tied to each listener, and invades each listener’s space. Everyone’s experience is identical in the sense that they’re all treated to the same visual and auditory vantage point. But everyone’s experience is unique because each experiences themselves as the target – each believes they have a special targeted vantage point.

The difference, then, between a live show seen up close and a 3D movie of the same show is that the former pulls just one or several audience members into the thick of the story, whereas 3D movies have this effect on everyone. Part of the fun of 3D movies is not, then, that they are 3D at all. We can have the same fun when we happen to be the target in a real-live show. The fun is in being targeted. When the show doesn’t merely leap off the screen, but leaps near you, it fundamentally alters the emotional experience. It no longer feels like a story about others, but becomes a story that invades your space, perhaps threateningly, perhaps provocatively, perhaps joyously. No, we don’t suffer the indignity of 3D glasses for the “popping out feeling”. We enjoy 3D movies because when we watch them we are no longer mere audience members at all.

Mark Changizi is a professor of cognitive science at Rensselaer Polytechnic Institute, and the author of The Vision Revolution (Benbella Books).

Read Full Post »

Today I was on LateNightLive (of ABC Radio National) with host Phillip Adam.  In addition to divulging my enjoyment at running over pigeons, I got a chance to talk about sex, blood, the blind, writing, rabbit-heads and other topics from The Vision Revolution.

Late Night Live

Late Night Live

Check out the segment here. (Download the mp3.)

Mark Changizi is a professor of cognitive science at Rensselaer Polytechnic Institute, and the author of The Vision Revolution (Benbella Books).

Read Full Post »

I was on the Lionel Show / Air America this morning, which was a blast!  Got to talk about my recent book, and about evolution, autistic savants, intelligent design, color, forward-facing eyes, illusions, and more. I really must get off the elliptical machine next time I do a radio show. Here’s the segment with me (or mp3 on your computer).

Mark Changizi is a professor of cognitive science at Rensselaer Polytechnic Institute, and the author of The Vision Revolution (Benbella Books).

Read Full Post »

This first appeared on October 26, 2009, as a feature at ScientificBlogging.com

Later this evening I’ll be giving a talk to a group of astronomers on what its like to see like an alien. The beauty of this is that I can speculate until the cows come home without fear of any counterexamples being brought to my attention. And even if an alien were to be among the audience members and were to loudly object that he sees differently than I claim, I can always just say that the jury is out until we get more data, and then advise him not to let the door slam into his proboscis on the way out.

E.T. the extra-terrestrial

E.T.'s forward-facing eyes suggests its ancestors evolved in forests

Although it may seem wild-eyed to discuss the eyes of aliens, if we understand why our vision is as it is, then we may be able to intelligently guess whether aliens will have vision like ours.

And in addition to the fun of chatting about whether little green men would see green, there are human implications. In particular, it can help us address the question, How peculiar is our human vision? Are we likely to see eye to eye with the typical alien invader? Or does our view of the world differ so profoundly that any alien visual mind would remain forever inscrutable?

Let’s walk through four cases of vision that I discuss in my book The Vision Revolution and ask if aliens are like us.

Do aliens see in color like us?

Let’s begin with color. I have argued in my research that our primate variety of color vision evolved in order to sense the skin color signals on the faces, rumps, and other naked spots of us primates. Not only are the naked primates the ones with color vision, but our color vision is at the sweet spot in design space allowing it to act like an oximeter and thereby see changes in the spectrum of blood in the skin as it oxygenates and deoxygenates. (See the journal article.)

Aliens may be interested in eating our brains, but they have no interest whatsoever in sensing the subtle spectral modulations of our blood under our skin. Aliens will not see color as we do, and will have no idea what we’re referring to when we refer to “little green men.”

Little green men may not think they look green

This can take the wind out of many people, namely those who feel that their senses give them an objective view of the world around them. But evolution doesn’t care about objective views of the world per se. Evolution cares about useful views of the world, and although veridical perceptions do tend to be useful, little-white-lie perceptions can also be useful. We primates end up with colors painted all over the world we view, but our color vision (in particular the red-green dimension) is really only meaningful when on the bodies of others. Although we feel as if the objects in our world “really” have this or that color, no alien would carve the world at the color-joints we do.

Do aliens have forward-facing eyes?

How about our forward-facing eyes we’re so proud of? I have argued and presented evidence that forward-facing eyes evolved as an adaptation to see more of one’s surroundings when one is large and living in leafy habitats. Animals outside of leafy cluttered habitats are predicted to have sideways-facing eyes no matter their body size, but forest animals are predicted to have more forward-facing eyes as they get larger. That is, in fact, what I found. (See the article.)

So, would aliens have forward-facing eyes? It depends on how likely it is that they evolved in a forest-like habitat (with leaf-like occlusions) and were themselves large (with eye-separation as large or larger than the typical occlusion width). My first reaction would be to expect that such habitats would be rare. But, then again, if plant-like life can be expected anywhere, then perhaps there will always be some that grow upward, and want to catch the local starlight. If so, a tree-like structure would be as efficient a solution as it is for plants here on Earth. The short answer, then, is that it depends. But that means that forward-facing eyes are fundamentally less peculiar than our variety of color vision. Aliens could well have forward-facing eyes, but it would not appear to be a sure thing.

Do aliens suffer from illusions?

One of the more peculiar things our brain does to us is see illusions. I have provided evidence that these illusions are not some arcane mistake, but a solution to a problem any brain must contend with if it is in a body that moves forward. When light hits our eye, we would like our perception to occur immediately. But it can’t. Perception takes time to compute, namely about a tenth of a second. Although a tenth of a second may not sound like much, if you are walking at two meters per second, then you have moved 20 cm in that time, and anything perceived to be within 20 cm of passing you would have just passed you – or bumped into you – by the time you perceive it. To deal with this, our brains have evolved to generate a perception not of the world as it was when light hit the eye, but of how the world will be a tenth of a second later. That way, the constructed perception will be of the present. Although there is no room in this piece to describe the details, I have argued that a very large swathe of illusions occur because the visual system is carrying out such mechanisms. (See the paper.)

Are aliens buying books of illusions and “ooh”ing and “ah”ing at them like we are? If they are moving forward (and have non-instantaneous brains), then they probably are buying these books. This is because the optic flow characteristics that underlie the explanation of the illusions are highly robust, holding in any environment where one moves forward. Aliens are, then, likely to suffer from illusions. The illusions we humans suffer from, then, may not be due to some arcane quirk or mistake in our visual system software, but, instead, a consequence of running the efficient software for dealing with neural delays.

Is alien writing shaped like ours?

I have provided evidence that our human, Earthly writing systems “look like nature,” in particular so that words have object-like structure. And I have shown that for writing like ours where letters stand for speech sounds, letters look like sub-objects, namely object junctions. Certain contour-combinations happen commonly in natural scenes, and certain combinations happen rarely. I have shown that the common ones in such environments are the common letters shapes found in human writing systems. Culture has selected writing to have the visual shapes our illiterate brains can see, which is why we’re such capable readers. (See the paper, a popular piece, and an excerpt from The Vision Revolution on this.)

Would alien writing look like this?

In this light, would alien writing look like nature as well? It depends on how specific one is when one says “like nature.” If, say, our human writing looks specifically like a savanna – i.e., if our writing mimicked signature visual features of the savanna – then it would appear very unlikely that aliens would have our kind of writing. But what if human writing looks like a very general notion of nature, so general it is likely to apply to most conceivable aliens? In my research I have provided evidence that the “nature” that appears relevant for understanding the shape of human writing is, indeed, highly general: namely, “3D environments with opaque objects strewn about.” Although highly general, aliens could float in a soup of cloudy transparent blobs, which is a kind of “nature” radically different than the one that human writing looks like. But it does seem plausible that most aliens will be roaming around opaque objects in 3D, and if that’s the case, then (so long as their culture has selected their writing to harness their visual object recognition system) their writing may look similar to human writing. Alien writing, if thrown into a pile of samples across our human writing, might just fit right in!

—-

So let’s take stock.

Would aliens have our color vision? No. Definitely not. Ours is due to our peculiar hemoglobin.

Would aliens have forward-facing eyes? Maybe. If they evolved in leafy habitats and were large.

Would aliens see our illusions? Probably.   If they move forward.

Would aliens have writing that looks like ours? Probably. If they live in a 3D world with opaque objects.

Mark Changizi is a professor of cognitive science at Rensselaer Polytechnic Institute, and the author of The Vision Revolution (Benbella Books).

Read Full Post »

Older Posts »