In this video I discuss peripheral color vision, including the common misconception that peripheral vision is completely black and white. By looking at the distribution of rods and cones throughout the retina, we can see that color vision extends to the far periphery. Next are two demonstrations, one showing that color can be perceived for a large stimulus, and another showing that color detection for a small stimulus is quite poor. To try the demo, visit www.randomcolour.com on your phone and then try identifying the color from several angles in your far peripheral vision.
For further reading on density estimates, motion detection, and peripheral color detection, see: Jonas JB, Schneider U, Naumann GO. Count and density of human retinal photoreceptors. Graefes Arch Clin Exp Ophthalmol. 1992;230(6):505-10. doi: 10.1007/BF00181769. PMID: 142713
M.P.S. To, B.C. Regan, Dora Wood, J.D. Mollon, Vision out of the corner of the eye, Vision Research, Volume 51, Issue 1, 2011, Pages 203-214, ISSN 0042-6989 https://doi.org/10.1016/j.visres.2010…. (https://www.sciencedirect.com/science…)
Tyler, C. W. (2015). Peripheral Color Demo. I-Perception, 6(6). https://doi.org/10.1177/2041669515613671
Video Transcript
Hi, I’m Michael Corayer and this is Psych Exam Review. In this video we’re going to look at color vision and specifically color vision in your peripheral vision in more detail. So you may have heard this misconception that some people might have which is that your peripheral vision can’t detect color. That it’s essentially black and white; that you can see color in the center of your vision but at the edges it’s black and white. Now what we’re going to do is look at why this isn’t true. So we’ll see that you can detect color in your peripheral vision but we’ll also look at where this misconception comes from because it turns out that your color perception in the periphery is quite poor.
So let’s start by talking about the physiology of your retina. So in each of your eyes you have about 100 million photoreceptors; these are receptors that respond to light and dark. About 92 million of these will be rods and rods detect light and dark. They work best in low light conditions and they can’t detect color or fine detail. And then you have cones and cones are how you detect color and fine detail and you have about six million of these in each eye. And you have three different types of cones, assuming you have normal color vision, and in order to detect colors accurately you need to stimulate all of these different types and the comparisons between how the light stimulates the different cones helps you figure out exactly what color it is.
So these rods and cones are not distributed evenly throughout the retina. If we look at the very center the fovea, or if we look at the center of the center, the foveola, this is the center of the fovea, we see that it’s entirely composed of cones there’s no rods here. And these cones are actually packed so tightly together they more closely resemble rods in their shape; they’re less cone-like in order to fit more of them in this very small space and then as we move away from the fovea so as we move the angle of eccentricity, which is the angle moving away from the fovea in either direction, we see a very sharp drop-off in the number of cones and you go from a maximum of somewhere around 150,000 cones per square millimeter of your retina in the foveola to only around two to three thousand cones per square millimeter in your retina in the far periphery.
And rods follow a different pattern. So as I said in the very center of the fovea there’s no rods at all and then as we move out a few angles then we see the highest concentration of rods somewhere around 150,000 per square millimeter and then this tapers off in the near periphery and then when we get to the far periphery it drops down to only about 30,000 to 40,000 rods per square millimeter.
Okay, so what does all this mean? Well it means that your color perception is going to be best in your fovea, in your central vision, but it also tells us that there are cones in the periphery, thousands of cones. And this means that you can detect color in the periphery. However, in order to detect the color accurately you’re going to need to have a large stimulus, so that it reaches enough cones that you can make those comparisons in order to detect the color accurately.
Okay, so we can demonstrate though, that because you have some cones in the edges of your retina that you can detect color in the far periphery. An easy way to demonstrate this is just to use your phone and go to this website randomcolour.com. What this page does is it just shows a random color each time you load the page. So if I reload this, it’s going to show me a different random color each time. And so what I’m going to do now is I’m going to reload this but I’m not going to see what color has loaded and I’m just going to sneak this into my peripheral vision. I’m going to slowly bring this in and right here I can already see sort of a maybe it’s a pinkish or a reddish color to it, even though it’s in my far periphery and I’ve kept my eyes straight ahead. And if I look you can see it is this pinkish color so I got this correct. And you can try this yourself; reload with a bunch of different colors, you can try this eye, you can try this eye, you could close one eye and do the periphery on the other side, and what you’ll find is that if you hold it close to your face so it’s a large stimulus, it’s going to hit a lot of the cones even though there’s not many available, it’s going to hit more of them and that’s going to allow you to detect the color accurately. So how can we show that our peripheral color vision is not very good?
Well, all we have to do here is make the stimulus smaller. And so in this case I’m going to cover more of the screen with my hand and I’m now going to hold it much farther away from my eye so that the surface area that’s hitting the retina is much smaller, so it’s not going to be stimulating nearly as many cones. And so here I’m going to reload the page, I’ll hold this in my periphery and I’m going to sneak this in again. I’m going to wiggle it because that allows me to see the motion. So right there I can see there’s something wiggling in my peripheral vision but I really have no idea what color it is. I’d really just have to guess. I can only see the motion, maybe it’s a light blue or something I really have no idea. Oh, okay it’s red, it’s really not what I expected. You can try this yourself and you’ll see that with a small stimulus you can’t detect color in the periphery.
Okay so this shows us where this misconception comes from, right? It is the case we can see color in our peripheral vision but not very well and not for small stimuli. And so if you only did this demo you might think “my periphery must be black and white. I can’t tell what color it is when it’s in my peripheral vision” but that’s only if it’s a small stimulus. So when you’re walking down a hallway, there’s a, there’s a wall next to you, let’s say it’s yellow, you can perceive that yellow color in your peripheral vision. But if there were some small details in there, maybe a pattern with another color, then you wouldn’t be able to detect that. And this all has to do with this distribution of rods and cones throughout the surface of the retina.
So I hope you found this helpful, I hope this cleared up some possible misconceptions. If so, please like the video and subscribe to the channel for more. And don’t forget to check out hundreds of other psychology tutorials that I have on the channel. Thanks for watching!
