I’m not sure if I understood the point you’re making, but it sounds like the point is that, even if the pixels are the same color, the important thing is to be able to distinguish the objects. To see that the tomato and banana are different things even if they have the same pixels. I suppose more generally the idea is that with an illusion, it may be an illusion in some lower level sense, but not an illusion in a more practical sense. Is that accurate?
The purpose[1] of our visual system—and, specifically, the purpose of our color vision—is to distinguish objects.
If, in the real world, you see a physical scene such as that pictured in the illustration, it may be that the spectral power distributions of the light reaching your eyes from the two identified regions of the physical checkerboard which you are looking at, will in fact match arbitrarily closely. However, you will correctly perceive the two squares as having different colors—i.e., as having different surface spectral reflectance functions—that being the practically relevant question which your visual system is designed to answer. (“What exactly is the spectral power distribution of the light incident upon my retina from such-and-such arc-region of my visual field” is virtually never relevant for any practical purpose.)
Similarly, if you see a photograph of a physical scene such as that pictured in the illustration, it may be that the spectral power distributions of the light reaching your eyes from the pixels representing the two identified regions of the physical checkerboard a picture of which you are looking at, will, again, match arbitrarily closely. But once again, you will correctly perceive the two pictured squares as having different colors—i.e., as having had, in the real-world scene of which the picture was taken, different surface spectral reflectance functions.
In both these cases, there is some real-world fact, which you are perceiving correctly. There is, then, some other real-world fact which you are not perceiving correctly (but which you also don’t particularly care about[2]). Once again: if I look at a real-world scene such as the one depicted, or a photograph of that scene, and I say “these two squares have different colors”, and by this I mean that the physical objects depicted have different colors, I am not mistaken; I am entirely correct in my judgment.
But! The picture in question is not a physical scene in the real world; nor is it a photograph of such a scene. It is artificial. It depicts something which does not actually exist, and never did. There is no fact of the matter about whether the identified checkerboard squares are of the same color or different colors, because they don’t exist; so there isn’t anything to be right or wrong about.
This means that the question—“are these two regions the same color, or different colors?”—is, in some sense, meaningless. Once again, the purpose of our visual system is to perceive certain practically relevant features of real-world objects. The “optical illusion” in question feeds that system nonsense data; and we get back a nonsense answer. But that doesn’t mean we’re answering incorrectly, that we’re making a mistake; in fact, there isn’t any right answer!
Once again, note that if we encountered this situation in the real world, we would correctly note that the two checkerboard squares have different colors. If we had to take some action, or make some decision, on the basis of whether square A and square B were the same color or different colors, we would therefore act or decide correctly. Acting or deciding on the basis of a belief that squares A and B are of the same color, would be a mistake!
Contrast this with, for example, color blindness. If I cannot see the difference between red and green, then I will have quite a bit of trouble driving a car—I will mis-perceive the state of traffic lights! Note that in this case, you can be sure that I won’t argue with you when you tell me that I am perceiving the traffic lights incorrectly; there is no sense in which, from a certain perspective, my judgment is actually correct. No; I simply can’t see a difference which is demonstrably present (and which other people can see just fine); and this is clearly problematic, for me; it causes me to take sub-optimal actions which, if I perceived things correctly, I would do otherwise (more advantageously to myself).
The takeaway is this: if you think you have discovered a bug in human cognition, it is not enough to demonstrate that, if provided with data that is nonsensical, weird (in a “doesn’t correspond to what is encountered in the real world” way), or designed to be deceptive, the cognitive system in question yields some (apparently) nonsensical answer. What is necessary is to demonstrate that this alleged bug causes people to act in a way which is clearly a mistake, from their own perspective—and that is far more difficult.
Furthermore, in the “optical illusion” example, if you insisted that the “right” answer is that A and B are the same color, you would (as I claim, and explain, above) be wrong—or, more precisely, you would be right in a useless and irrelevant way, but wrong in the important and practical (but still quite specific) way. Now, how sure are you that the same isn’t true in the happiness case? (For instance, some researcher says that beautiful people aren’t happier. But is this true in an important and practical way, or is it false in that way and only true in an irrelevant and useless way? And if you claim the former—given the state of social science, how certain are you?)
And if you decide that in some given case, you do care about this secondary fact, you can use tools designed to measure it. But usually, this other fact is of academic interest at best.
Thank you for a really great explanation, I understand now.
Now, how sure are you that the same isn’t true in the happiness case? (For instance, some researcher says that beautiful people aren’t happier. But is this true in an important and practical way, or is it false in that way and only true in an irrelevant and useless way? And if you claim the former—given the state of social science, how certain are you?)
I would say that I feel about 90% sure that it isn’t true in the happiness case. I am not particularly familiar with the research, but in general, we have a ton of blind spots and biases that are harmful in a practical, real world sort of sense, and so a claim that we also have one in the context of happiness seems very plausible. It also seems plausible because of the evopsych reasoning. And most of all, reputable scientists seem to be warning us about the pitfalls of thinking we know what we like. If they were just making an academic point that we have these blind spots, but these blind spots aren’t actually relevant to everyday people and everyday life, I wouldn’t expect there to be bestselling books about it like Stumbling on Happiness.
But, it is definitely possible that I am just misinterpreting and misunderstanding things. If I am—if we aren’t actually getting something wrong about happiness that is important in a practical sense—then that is very important. So that I can update my beliefs, and so that I can either edit or delete this post.
Blind spots and biases can be harmful to your goals without being harmful to your reproductive fitness. Being wrong about which future situations will make you (permanently) happier is an excellent example of such a blind spot.
if you insisted that the “right” answer is that A and B are the same color, you would (as I claim, and explain, above) be wrong—or, more precisely, you would be right in a useless and irrelevant way, but wrong in the important and practical (but still quite specific) way. Now, how sure are you that the same isn’t true in the happiness case?
An excellent point! I wonder how one can figure out this distinction in the hedonic case.
Picture-data presented to the visual cortex can be for novel situations. It might be the only evidence for the truth of the matter seen. It would seem that criteria for correct seeing should still exist. Therefore saying that the picture is artifical is not particularly relevant. It being artificial might be that it is likely to present an edge case that would not be encountered naturally. But seeing phenomena that are totally unlike anything encountered previuosly is a thing that living organisms might need to deal with. In order to build a working behavoiur for novel situations it is important that the sense organ behaves consistently and not randomly (if truly no criteria then random noise would be valid behaviour) even if the consistentcy that is settled on is picked arbitrarily.
If I cannot see the difference between red and green, then I will have quite a bit of trouble driving a car—I will mis-perceive the state of traffic lights!
Unless they are conveniently arranged in a set way, which you may memorize, such as left to right/bottom to top = red, yellow, green.
Lest anyone get the idea that the parent comment is being ignored merely because it’s “pedantic” or “misses the point” or some such, I want to point out that it’s also mistaken.
This fascinating and engrossing document is Part 4 of the Manual of Uniform Traffic Control Devices for Streets and Highways (a.k.a. “MUTCD”), published by the Federal Highway Administration (a division of the United States Department of Transportation).
Page 468 of the MUTCD (p. 36 in the PDF) contains this diagram:
And page 469 of the MUTCD (p. 37 in the PDF) contains this diagram:
Note that the iconography is the same and the orientation and arrangement is the same. But the colors are different!
For another example, take a look at MUTCD p. 487 vs. p. 488 (PDF pp.55–56).
In summary, it is not possible to reliably determine the colors of traffic control signals from their positions in a traffic light arrangement.
The purpose[1] of our visual system—and, specifically, the purpose of our color vision—is to distinguish objects.
If, in the real world, you see a physical scene such as that pictured in the illustration, it may be that the spectral power distributions of the light reaching your eyes from the two identified regions of the physical checkerboard which you are looking at, will in fact match arbitrarily closely. However, you will correctly perceive the two squares as having different colors—i.e., as having different surface spectral reflectance functions—that being the practically relevant question which your visual system is designed to answer. (“What exactly is the spectral power distribution of the light incident upon my retina from such-and-such arc-region of my visual field” is virtually never relevant for any practical purpose.)
Similarly, if you see a photograph of a physical scene such as that pictured in the illustration, it may be that the spectral power distributions of the light reaching your eyes from the pixels representing the two identified regions of the physical checkerboard a picture of which you are looking at, will, again, match arbitrarily closely. But once again, you will correctly perceive the two pictured squares as having different colors—i.e., as having had, in the real-world scene of which the picture was taken, different surface spectral reflectance functions.
In both these cases, there is some real-world fact, which you are perceiving correctly. There is, then, some other real-world fact which you are not perceiving correctly (but which you also don’t particularly care about[2]). Once again: if I look at a real-world scene such as the one depicted, or a photograph of that scene, and I say “these two squares have different colors”, and by this I mean that the physical objects depicted have different colors, I am not mistaken; I am entirely correct in my judgment.
But! The picture in question is not a physical scene in the real world; nor is it a photograph of such a scene. It is artificial. It depicts something which does not actually exist, and never did. There is no fact of the matter about whether the identified checkerboard squares are of the same color or different colors, because they don’t exist; so there isn’t anything to be right or wrong about.
This means that the question—“are these two regions the same color, or different colors?”—is, in some sense, meaningless. Once again, the purpose of our visual system is to perceive certain practically relevant features of real-world objects. The “optical illusion” in question feeds that system nonsense data; and we get back a nonsense answer. But that doesn’t mean we’re answering incorrectly, that we’re making a mistake; in fact, there isn’t any right answer!
Once again, note that if we encountered this situation in the real world, we would correctly note that the two checkerboard squares have different colors. If we had to take some action, or make some decision, on the basis of whether square A and square B were the same color or different colors, we would therefore act or decide correctly. Acting or deciding on the basis of a belief that squares A and B are of the same color, would be a mistake!
Contrast this with, for example, color blindness. If I cannot see the difference between red and green, then I will have quite a bit of trouble driving a car—I will mis-perceive the state of traffic lights! Note that in this case, you can be sure that I won’t argue with you when you tell me that I am perceiving the traffic lights incorrectly; there is no sense in which, from a certain perspective, my judgment is actually correct. No; I simply can’t see a difference which is demonstrably present (and which other people can see just fine); and this is clearly problematic, for me; it causes me to take sub-optimal actions which, if I perceived things correctly, I would do otherwise (more advantageously to myself).
The takeaway is this: if you think you have discovered a bug in human cognition, it is not enough to demonstrate that, if provided with data that is nonsensical, weird (in a “doesn’t correspond to what is encountered in the real world” way), or designed to be deceptive, the cognitive system in question yields some (apparently) nonsensical answer. What is necessary is to demonstrate that this alleged bug causes people to act in a way which is clearly a mistake, from their own perspective—and that is far more difficult.
Furthermore, in the “optical illusion” example, if you insisted that the “right” answer is that A and B are the same color, you would (as I claim, and explain, above) be wrong—or, more precisely, you would be right in a useless and irrelevant way, but wrong in the important and practical (but still quite specific) way. Now, how sure are you that the same isn’t true in the happiness case? (For instance, some researcher says that beautiful people aren’t happier. But is this true in an important and practical way, or is it false in that way and only true in an irrelevant and useless way? And if you claim the former—given the state of social science, how certain are you?)
In the “survival-critical task which is the source of selection pressure to develop and improve said system” sense.
And if you decide that in some given case, you do care about this secondary fact, you can use tools designed to measure it. But usually, this other fact is of academic interest at best.
Thank you for a really great explanation, I understand now.
I would say that I feel about 90% sure that it isn’t true in the happiness case. I am not particularly familiar with the research, but in general, we have a ton of blind spots and biases that are harmful in a practical, real world sort of sense, and so a claim that we also have one in the context of happiness seems very plausible. It also seems plausible because of the evopsych reasoning. And most of all, reputable scientists seem to be warning us about the pitfalls of thinking we know what we like. If they were just making an academic point that we have these blind spots, but these blind spots aren’t actually relevant to everyday people and everyday life, I wouldn’t expect there to be bestselling books about it like Stumbling on Happiness.
But, it is definitely possible that I am just misinterpreting and misunderstanding things. If I am—if we aren’t actually getting something wrong about happiness that is important in a practical sense—then that is very important. So that I can update my beliefs, and so that I can either edit or delete this post.
..but which don’t get selected out, for some reason.
Blind spots and biases can be harmful to your goals without being harmful to your reproductive fitness. Being wrong about which future situations will make you (permanently) happier is an excellent example of such a blind spot.
An excellent point! I wonder how one can figure out this distinction in the hedonic case.
Picture-data presented to the visual cortex can be for novel situations. It might be the only evidence for the truth of the matter seen. It would seem that criteria for correct seeing should still exist. Therefore saying that the picture is artifical is not particularly relevant. It being artificial might be that it is likely to present an edge case that would not be encountered naturally. But seeing phenomena that are totally unlike anything encountered previuosly is a thing that living organisms might need to deal with. In order to build a working behavoiur for novel situations it is important that the sense organ behaves consistently and not randomly (if truly no criteria then random noise would be valid behaviour) even if the consistentcy that is settled on is picked arbitrarily.
Unless they are conveniently arranged in a set way, which you may memorize, such as left to right/bottom to top = red, yellow, green.
Lest anyone get the idea that the parent comment is being ignored merely because it’s “pedantic” or “misses the point” or some such, I want to point out that it’s also mistaken.
This fascinating and engrossing document is Part 4 of the Manual of Uniform Traffic Control Devices for Streets and Highways (a.k.a. “MUTCD”), published by the Federal Highway Administration (a division of the United States Department of Transportation).
Page 468 of the MUTCD (p. 36 in the PDF) contains this diagram:
And page 469 of the MUTCD (p. 37 in the PDF) contains this diagram:
Note that the iconography is the same and the orientation and arrangement is the same. But the colors are different!
For another example, take a look at MUTCD p. 487 vs. p. 488 (PDF pp.55–56).
In summary, it is not possible to reliably determine the colors of traffic control signals from their positions in a traffic light arrangement.