Mark Changizi

speaker

236 appearances 1 recordings 1 series first heard Nov 2024 last heard Nov 2024

Mark Changizi’s voice in public audio — every appearance, attributed to the second.

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The Jordan B. Peterson Podcast · 502. Angry and Red: Color as Emotion | Mark Changizi · 28 Nov 2024 podcast

It's certainly possible, but it wouldn't have driven... There's no reason... To think that fruit would have driven those particular wavelength sensitivities of the middle and long wavelength sensitive cones.

Right.

Yeah. And there's all kinds of things where we leverage our color vision, which is peculiarly for empath kind of health senses. But we obviously use it for lots of things probably in nature beyond that and in culture. Yeah. It's all over the place. Yeah. But that doesn't amount to an explanation for what drove it.

Right. Well, so everything might be multipurpose, but the odds of there being two competing or multiple competing desiderata that are determining the design, that they're close to one another, are going to be typically fairly rare. Typically, one of them might be 10 times more important than the other.

Or a thousand times more important. Usually, in my experience, it turns out that one of these is the principal drivers. It can explain first-order, even second-order properties of the thing. And yeah, there can be other third or fourth order stuff, but that's mostly irrelevant. So you can get away with explaining. So for example, another one, why we have forward-facing eyes. Standard story.

And the fun thing of all of these explanations, whether it's pruning fingers, it's still probably in the Wikipedia page. It says it's a side effect of osmosis or some bull crap, right? It's still there to this day, these old narratives. And then for forward-facing eyes, it's always something about predators want forward-facing eyes. Except that every fish is a predator eating a smaller fish.

All the birds are predators. They all have sideways-facing eyes. By our standards, they're all sideways-facing eyes. Even all the carnivores, the paradigmatic mammalian meat-eaters, predators, have sideways-facing eyes relative to us. I mean, they still have forward-facing eyes in terms of the big picture of things. So there's a lot of variability in forward-facing eyeness across the mammals.

And the question is, why is there this variability? And so there's been multiple kinds of... One is stereoscopy, better stereoscopy. But you even get stereoscopy in a bunny rabbit. Bunny rabbit has a very thin binocular field, and it can see stereoscopy within a thin binocular field. But it also gets the benefit of seeing everything. It can see directly behind it, below it, above it.

So you've got this full panoramic vision, whereas we've chosen to lose... Right, a lot. Half of our visual field, or a lot of our visual field, just to have better stereoscopy up in front. Now, so one of the bad sorts of, you have these two currencies, like the standard argument is, oh, I've got this great wide stereoscopy field of better 3D vision up front at the expense of losing everything.

How do you balance those things? How is that an argument that I would want more of of apples to have while getting less adverbs in the back and not even obviously comparable things that I can trade off. So my argument was like, first of all, stereoscopy is not, it's the least important 3D sense. We have all of these, there's many, many three-dimensional senses.

One is just what kinds of objects they are, how far down towards the horizon, Are they? How they overlap? Things, yeah, occlusions in front of other things. If I just do this with one eye, even with one eye, I'm getting amazing. Right, right. Much better than stereoscopy.

All of these things, if you're a perception psychologist who creates stimuli that have competing cues of two different kinds, and they say, which one's Trump? Stereoscopy loses always. All of these other ones trump. They win if there's competing. Oh, yeah.

And so none of the... Stereoscopy always loses. And if you've played first-person shooter video games, you're... Yeah, you have both eyes open, but you're being fed one image on screen. And these things are so immersive. You never are confused as to where the guys are that you're shooting, right? They're always really unambiguously in one particular spot, yet you're a cyclops, right?

So it had occurred to me back then. I said, I don't think it has anything to do with stereoscopy whatsoever. And it turns out it's all about one currency. This is again to this idea of why... Why aren't there three, two or three or more equivalent kinds of functions that are all competing? And then it's just some ugly mess and it's not a good design hypothesis at all.

It's going to be sort of ugly kludge that happens to – it's almost never a kludge. And so in this case, the reason that we have forward-facing eyes and the more forward-facing they are is to see better in clutter. And so what I mean by that, animals that evolved with leaves all over the place. When there's leaves, if your eyes are more widely separated than the clutter leaves, let's say.

So, for example, if you've played this game, if I hold my finger up in front of you, it's very thin, and I look at you, but not my finger, I see two copies. Unless I've got a dominant eye, but for those of you who don't have a dominant eye, you'll see two copies of your finger, and each will be semi-transparent.

Right. Now, you can see through it. Right. So what one eye is being blocked with, the other eye is seeing the world beyond that. And so your brain has evolved to just create two copies of it. And you're not confused like, oh, my God, I've got two figures. No, you know what's going on. It's just you have this perception that combines them and creates semi-transparency so that you can see beyond it.

Now, even my whole hand, I'm almost missing nothing, even with my whole hand in front of me. There's a little bit of a core in the middle, but I'm capturing most of it.

So for objects that are not as big as this interpupillary distance, the separation between my eyes, then when you're an animal with those kinds of eyes in a forest with leaves that are typically smaller than that, you actually get, I call it x-ray. You actually can see, it's probabilistic summation. You actually can see much, much more of the environment beyond than when you're a cyclops.

So, and in fact, I noticed this playing video games back 20 something years ago, when I would be, you know, because you're a cyclops and you're hiding in bushes and I'd be trying to snipe people. And then when you're in a bush, you can't see anything. Of course, these are fake bushes, I get it.

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