= 27d567bc2d48d9f40e9ccc20ea370b15)
AndyWood comments on Bizarre Illusions - Less Wrong
You are viewing a comment permalink. View the original post to see all comments and the full post content.
= 783df68a0f980790206b9ea87794c5b6)
Loading…= b715d02e85f7b3b4ae65ca3d3e450868)
Subscribe to RSS Feed
Powered by Reddit
= f037147d6e6c911a85753b9abdedda8d)
You are viewing a comment permalink. View the original post to see all comments and the full post content.
Comments (305)
As others have pointed out, the difficulty here is more in the semantics of "color" than in the optics.
As a simplification, we can consider the projected color.P of a tile to be a product of its surface properties (color.S) and the intensity of the incident light. The illusion straightforwardly contrives one of these terms - the light intensity - so that the color.P of tile A equals the color.P of tile B. But the brain, interpreting the image as a 3D scene with light and shadow, reports the color.S-es of the tiles, which are different under that very reasonable and useful interpretation.
I'm sorry if this is a big distraction from the point of your post. I'm still interested in the point, so perhaps you can find another way of getting it across.
Yeah. I missed the semantic shift. All it took was someone pointing out that there were two uses of Color drifting around and almost all the comments snapped back into making sense.
The point is that an illusion generally gives off a sense of bizarreness because we are expecting X but the illusion gives us Y. In the case of the color example, I once expected boxes A and B to appear to be the same color (perceived) if and only if they were the same color (RGB). The illusion shows this is not the case. Being curious, I sought to understand the underlying principles behind why we perceive two different colors. Once this is understood, the illusion should no longer seem bizarre but a trivial example of the underlying principles.
In trying to find where I went wrong with the post, I come up with this:
I am half tempted to take this post down, rewrite it, and put it back up, but I don't know how much that would help.
Well, don't do anything that takes down the comment section. Many of the comments are insightful and, um, say things that should have been in your original post.
Demystifying optical illusions, and visual cognition in general, is a very good exercise in rationalist reduction.
Okay. Do you think it would be valuable to just edit the post in place?
As best as I can tell, these are the trouble paragraphs:
Is this better?:
It seems to me that you are still using the word colour in a way that suggests you haven't really grasped the insight that makes this illusion seem not-bizarre. That insight is fundamentally that the statement "this ball is blue" is not equivalent to the statement "a digital photo of a scene containing this ball would have pixel values of 0, 0, 255 at pixel locations where light from the ball reached the sensor". It is a much more complex (and more useful) statement than that. The bad assumption is that 'colour' when used to refer to a property of objects in the world determined through visual perception has any simple relationship with RGB values recorded by a digital camera. You still seem to be talking as if RGB values are somehow 'true' colours.
Especially in the case of human tetrachromats.
I am trying to find a way to say what you said with one phrase or word. I feel like I am struggling to find a term.
I think the key for me in understanding this type of illusion (and the general phenomenon of colour constancy) was to realize that 'colour' in common usage ("this ball is blue") is perceived as a property of objects and we infer it indirectly based on light that reaches our retinas. That light also has a 'colour' (subtly different meaning) but it is not something we perceive directly because it is not very useful in itself.
This makes perfect sense when you think about it from an evolutionary perspective - we evolved to recognize invariant properties of objects in the world (possibly fruit in trees for primates) under widely varying lighting conditions. Directly perceiving the 'colour' (RGB) of light would not tell us anything very useful about invariant object properties. There is enough overlap between the two meanings of colour for them to be easily confused however and that is really the root of this particular illusion.
In computer graphics we commonly use the term 'material' to describe the set of properties of a surface that govern how it responds to incident light. This encompasses properties beyond simple colour ("shiny blue ball", "matte blue ball", "metallic blue ball"). I don't know if that usage is well understood outside of the computer graphics field however.
I completely agree with you. At this point, I am just trying to clean up the article to help clarify the answer behind the illusion. Does the phrase, "I should stop thinking that the visual system is reporting RGB style colors" mesh okay? That is the only location of RGB as of this edit.
Yes, I think 'RGB colours' is better than 'True Colours' in this context.
Thanks. Do you have any other suggestions that may help clarify the article? Your explanations have been very helpful. Learning the terms was apparently something I never bothered to do. Oops. :P
How is "Color gross of lighting conditions"?
It sounds like you're trying to come up with a sentence or two that captures all of the insight on color that the commenters have given. While I'm a big fan of summarizing, and a big critic of those who can't, I don't think you can get it to work here. Instead of your final bolded change (the others are good), just point to or quote a few good comments that show what the visual system is doing, and how the optical illusions trick it.
How about:
EDIT: I updated it with something similar. Hopefully it was an improvement. :) Thanks again for your help (which isn't to say that I wouldn't mind more help...)
Taking this and SilasBarta's thoughts together: can you apply this same meta-principle to something substantially different in a new post, written with a recognition of these confusions? That post could cite this post with a "Followup to:" line, and elaborate on your discovery in some way.
Would it be better to just replace the content of this post? I can archive the original in a comment here for future context.
I would be disinclined to that course, but hard-pressed to justify it more effectively than by my idiosyncratic generalization of one of a number of principles I have heard - I quote from the post:
I don't think you have anything to be ashamed of in this post. It's not deep, it's not extraordinary in its conclusions, but it is correct and brief. The complaints seem to me best addressed by elaboration and discussion - things which require far more than a brief edit placed at the end of the post.
As SilasBarta mentioned, there's a lot of commentary on this post that is worth preserving, and should be preserved with the original post. It would be unfair to the commenters to render their comments incomprehensible - even briefly - by distortion of that to which they responded.
And, if I may be frank, if the idea which inspired this post is interesting, it is probably capable of generalization. The idea of my own which I promoted to a post I did so because I saw that it was applicable beyond the scope of its origination, and in a manner which was natural, elegant, and interesting. It proved of interest to a number of people here, despite its unabashedly algebraic treatment. If you can find a profitable extension of your concept, it will be likely to be worth reporting in a followup post (and if you are concerned about the appropriateness of it, I - as one remaining upvoter of the OP - will have sent my email to you in a PM, and be willing to comment on any draft you wish to send).
If you cannot find a profitable extension of your concept, it is probably not worth the time to revise. Consider your post dubiously successful (it is still in positive territory, is it not?) and leave it be.
It's not so much that I am ashamed; I am just frustrated. The behavior of this post caught me completely off-guard. It was upvoted to +5 within a few hours and people started asking questions. After my responses, the post dropped to +1. The karma itself doesn't mean much to me, but the feedback here was evidence of something greater than a non-interesting or incorrect post.
People were willing to talk about it, so I stuck it out for as much feedback as I could. The investment was completely worth it. I got several comments worth of extremely valuable insights to my writing style and how to better post here at LessWrong.
I think the post itself failed, but the whole experience has been a net gain.
I agree. My intent in the revisions has been to keep people from being distracted by my quirks and leading them into a wonderful discussion in the comments. This particular illusion has a lot more history behind it than I originally thought; I learned a lot.
Thank you very much. I have to sit on the events of today and ponder if there is a next step to take. If a followup is coming I will certainly take you up on your offer.
An addendum - as far as my recollection of the original goes, your edits appear reasonable, although I would not have risked them on my own post. I congratulate you on a successful revision, but my offer stands.