# Evolutionary Advantage to Hearing Octaves as "The Same?" **URL:** \ **Category:** Factual Questions\ **Created:** [March 12, 2007, 5:44am UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567 "2007-03-12T05:44:16Z")\ **Posts on this page:** 20\ **Page:** 8
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [March 14, 2007, 3:38pm UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/141 "2007-03-14T15:38:14Z")
[QUOTE=Brain Wreck] I have no objection to any nuanced scenario where any other interval was seen as “most similar”, provided that (and this is the important part) no other interval pair that is mathematically _more similar_ would be seen as _less similar_. I can accept a scenario where fifths and octaves are seen with an equal amount of “sameness”. I explicitly reject any scenario where an interval of fifths is perceived as more similar than an interval of octaves. Please do not attribute any acceptance of such a scenario to me. [/quote] I see. And this does nearly resolve the contradiction I mentioned in my previous post. In that post, I pointed out that you have two views: 1. If it had been advantageous to do so, we could have evolved to hear fifths as “the same,” 2. Evolution can not but give organisms perceptual systems which yield similarity judgments which track, directly, objective physical similarities. I said the second implies that nothing could evolve which hears fifths as “the same” since fifths _aren’t_ the same. This contradicts the first view. However, as you point out, the second view I attribute to you shouldn’t be taken to mean that evolution can’t collapse some objective distinctions. Of course perceptual system collapse some objective distinctions. I see two red patches as “the same” even though their wavelenths differ at least slightly. It even happens (as in the case of “metamers”) that I can see color patches as “the same” whose spectral properties differ quite widely. I’ll stipulate there’s no contradiction here after all, if the second view is understood in the right way. Your second view does imply, again, as you point out, that fifths couldn’t be heard as _more_ similar than octaves. As you know, this is the view I disagree with. I’ve explained why I disagree, on both logical and empirical grounds. I’ve explained that I think there is objective, empirical evidence that the view is controverted by our own perceptual system in at least three ways (I’ve named them previously in this thread,) and I’ve told you how you can make your view more plausible (by finding what I called a “dimension of similarity” in the physical world which our own color judgments directly track). I also understand you grow weary of this discussion, and I do not blame you. And as I’ve said, I find this particular claim that we’ve been discussing for the last several posts to be in no way central to the concern of the thread, nor to my own personal concern. I’m happy to discuss it, and I’m also happy to move the discussion somewhere else, and I’m also happy to let it drop. I think we’ve both had our say. -FrL- ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [March 14, 2007, 3:39pm UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/142 "2007-03-14T15:39:59Z")
[QUOTE=Exapno Mapcase] If you didn’t want an answer, why did you ask the question? [/QUOTE] Sorry, I don’t get it. Why do you say I didn’t want an answer? -FrL- ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [March 14, 2007, 3:58pm UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/143 "2007-03-14T15:58:44Z")
[QUOTE=Frylock] Sorry, I don’t get it. Why do you say I didn’t want an answer? -FrL- [/QUOTE] :smack: ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [March 14, 2007, 4:00pm UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/144 "2007-03-14T16:00:46Z")
[QUOTE=Exapno Mapcase] :smack: [/QUOTE] 😕 Please be kind and explain. 🙂 (Or if someone else reading is less dense than I\*, perhaps they could extend a hand…) -FrL- \*Hmm… should that be “I” or “me?” Come to think of it, I think either works, but “me” sounds less ostentatious. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [March 14, 2007, 4:04pm UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/145 "2007-03-14T16:04:04Z")
[QUOTE=RaftPeople] Not only have you posted numerous incorrect statements, **Frylock** has patiently and courteously responded to you in every case that I have read. [/QUOTE] You got some examples of “numerous” incorrect statements which **Exapno Mapcase** has posted in this thread? Without getting into specifics (unless he’d like me to), the only statement of his I’d take issue with is his assertion that most of the Sun’s output is in the visible. If not, I’d suggest you owe him an apology. ---
**Author:** ![garygnu](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garygnu/32/2924_2.png) [@garygnu](https://boards.straightdope.com/u/garygnu)\ **Post date:** [March 14, 2007, 4:06pm UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/146 "2007-03-14T16:06:23Z")
I think **Frylock** has a piont, but I’m still trying to figure out what it is, exactly. I don’t think comparing sound and light works because sound wave combine, interact, and interfere with each other in a manner that light does not. One obvious reason two notes close to each other sound dissimilar, **Punoqllads** , is that the sound waves interfere with each other in a [rather unpleasant way](http://en.wikipedia.org/wiki/Consonance_and_dissonance#The_objective_basis_of_dissonance) (I actually like a little dissonance in my music, but it’s very easy to hear the difference). Check out [this chart](http://upload.wikimedia.org/wikipedia/en/f/f9/Dissonance-a220-a440-notated.jpg) to see visually why octaves sound similar. ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [March 14, 2007, 5:16pm UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/147 "2007-03-14T17:16:16Z")
[QUOTE=garygnu] I think **Frylock** has a piont, but I’m still trying to figure out what it is, exactly. [/quote] To my recollection, the claims I have made at various times for various reasons on this thread are: > [@post 68](#): > > 1. I now know that octaves are objectively similar in a way that other intervals are not. > > 2. This is most of the explanation as to why I hear octaves as similar. > > 3. Their objective similarity does not necessitate my hearing them as similar. But it would tend very usually to cause organisms to hear them as similar. > > 4. We tend to hear things that are objectively similar as similar, not because of any logical point about a necessitation relation between objective and perceptual similarity, but rather, because it is generally (though not always) best for us as organisms that we percieve objectively similar things as similar. And in addition, lately, 1. It is possible, and it has in fact actually occured, that a creature evolve a perceptual apparatus which gives rise in that creature to judgments of similarity, which do not directly reflect similarities found in the creature’s environment. In other words, (I can think of no better way to make clear what I’m saying than this, for which my apologies): A perceptual system P could evolve which is designed to measure X, for which there are four instances of X, namely, i1, i2, i3 and i4, which are such P judges i1 and i2 to be “more similar” than i3 and i4, (let’s notate the creature’s judgment thus: “S(i1, i2) \> S(i3, i4)”), where i1, i2, i3, and i4 are also such that, given any respect R in which i1 and i2 are objectively more similar than i3 and i4, there is another quartet of instances of X, namely i5, i6, i7 and i8, which are such that under respect R, i5 and i6 are objectively more similar than i7 and i8, and yet P judges “S(i7, i8) \> S(i5, i6).” That, in a very complicated nutshell, is what I’ve been arguing for in the latest posts in this thread. Today I’ll try to give some thought as to how to do a better job of making this more concrete. -FrL- ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [March 14, 2007, 5:23pm UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/148 "2007-03-14T17:23:30Z")
[QUOTE=garygnu] I don’t think comparing sound and light works because sound wave combine, interact, and interfere with each other in a manner that light does not. One obvious reason two notes close to each other sound dissimilar, **Punoqllads** , is that the sound waves interfere with each other in a [rather unpleasant way](http://en.wikipedia.org/wiki/Consonance_and_dissonance#The_objective_basis_of_dissonance) (I actually like a little dissonance in my music, but it’s very easy to hear the difference). Check out [this chart](http://upload.wikimedia.org/wikipedia/en/f/f9/Dissonance-a220-a440-notated.jpg) to see visually why octaves sound similar. [/QUOTE] (Sorry, I didn’t mean to ignore the rest of your post. Unfortunately I have to run off to school now, but I’m just registering here my apologies.) -FrL- ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [March 14, 2007, 5:24pm UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/149 "2007-03-14T17:24:42Z")
[QUOTE=Frylock] 1. It is possible, and it has in fact actually occured, that a creature evolve a perceptual apparatus which gives rise in that creature to judgments of similarity, which do not directly reflect similarities found in the creature’s environment. In other words, (I can think of no better way to make clear what I’m saying than this, for which my apologies): A perceptual system P could evolve which is designed to measure X, for which there are four instances of X, namely, i1, i2, i3 and i4, which are such P judges i1 and i2 to be “more similar” than i3 and i4, (let’s notate the creature’s judgment thus: “S(i1, i2) \> S(i3, i4)”), where i1, i2, i3, and i4 are also such that, given any respect R in which i1 and i2 are objectively more similar than i3 and i4, there is another quartet of instances of X, namely i5, i6, i7 and i8, which are such that under respect R, i5 and i6 are objectively more similar than i7 and i8, and yet P judges “S(i7, i8) \> S(i5, i6).” [/quote] I should have noted, its this fifth claim which is the one that I and **Brain Wreck** and a few others have been arguing about very lately in this thread. -FrL- ---
**Author:** ![RaftPeople](https://avatars.discourse-cdn.com/v4/letter/r/6f9a4e/32.png) [@RaftPeople](https://boards.straightdope.com/u/RaftPeople)\ **Post date:** [March 14, 2007, 10:24pm UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/150 "2007-03-14T22:24:44Z")
[QUOTE=Q.E.D.] You got some examples of “numerous” incorrect statements which **Exapno Mapcase** has posted in this thread? Without getting into specifics (unless he’d like me to), the only statement of his I’d take issue with is his assertion that most of the Sun’s output is in the visible. If not, I’d suggest you owe him an apology. [/QUOTE] Actually, the sun info is correct, it peaks in the visible spectrum. Other stuff is not so correct. > [@Exapno Mapcase](#): > > The reason we see in a certain frequency of electromagnetic radiation is that this is the dominant radiation in the spectrum given by the sun. The physics of light waves are there first. It might be helpful to see in the infrared or ultraviolet but evolution is about being good enough not about being perfect. Visible is dominant EMR from sun: Correct. The reason we see it: Because there is an advantage for us to see it. Not simply because it is there. We do not detect all that there is, we detect what has helped us survive. “It might be helpful to see in the infrared or ultraviolet but evolution is about being good enough not about being perfect” Bees see ultraviolet light because it helps them detect the right flowers. Each organism that occupies a different niche of the environment will potentially have a different set of characteristics. Your statement appears to be ignoring this. > [@Exapno Mapcase](#): > > However, the ability to see colors is a mathematical consequence of the ability to see light in the first place. There’s no meaning is asking why we evolved to see blue. Wrong. Some creatures are color blind (you realize this, right?). Some creatures see portions of the spectrum we don’t. Some creatures have a more advanced ability to distinguish colors. > [@Exapno Mapcase](#): > > This is another way of saying that it’s all about physics, not biology. Wrong. It is a combination of what is available (physics) and what physical/neural structures have evolved to detect the sensory input. The biology can range from simple to very complex in it’s ability to react to external stimulus. Once that has occured, there is a wide range of processing that can occur within the brain to organize/categorize/interpret the incoming signals. Our sensory perceptions are a combination of physics, biological mechanisms that are sensitive to the stimulus and neural structures in the brain to process the incoming signals. > [@Exapno Mapcase](#): > > Worse, in this thread you posted something **no one understood** , I understood **Frylock’s** posts so that is factually incorrect. Furthermore, a number of posters seemed to understand and responded accordingly. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [March 14, 2007, 10:37pm UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/151 "2007-03-14T22:37:48Z")
[QUOTE=RaftPeople] Actually, the sun info is correct, it peaks in the visible spectrum. [/QUOTE] The peak, yes. But visible light only counts for just under half the total solar radiance. [Cite](http://earthobservatory.nasa.gov/Library/SORCE/sorce_02.html). He said “most” not “peak”, which is pretty well the sum total of the issue I had with that statement. As for the rest, well, I’m no biology expert so I’ll let you two discuss it. ---
**Author:** ![Triskadecamus](https://avatars.discourse-cdn.com/v4/letter/t/b19c9b/32.png) [@Triskadecamus](https://boards.straightdope.com/u/Triskadecamus)\ **Post date:** [March 14, 2007, 11:23pm UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/152 "2007-03-14T23:23:45Z")
Frylock, The mechanical system in the ear that detects frequency will detect harmonic frequencies best if they are simple multiples. You will experience more input to the sectors of the brain that respond to each octave A than you will for each third, or fifth. (Not zero, but less.) So, a neural system that associates tones by octaves will be better able to discriminate tones than one which relies on other harmonic pairs. In other words, if I was categorizing by every possible harmonic, I would have too much similarity among all the notes, and not enough differences to discriminate. If I receive A, and sympathetic vibrations of the octave below it, and the octave above, I know from learned experience what that note is. If I receive thirds and fifths, the reinforcement is less in magnitude, and since many other beat frequencies will be received as well, it serves my need to discriminate tone better if my brain ignores all but one set of harmonics, the integer multiples being the simplest. So, long ago species with the need to discriminate tone developed brain structures that accommodated the process of intensifying integer harmonics, and the octave was born. Biology manages to accommodate physics. Tris ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [March 14, 2007, 11:41pm UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/153 "2007-03-14T23:41:43Z")
[QUOTE=Triskadecamus] Frylock, The mechanical system in the ear that detects frequency will detect harmonic frequencies best if they are simple multiples. You will experience more input to the sectors of the brain that respond to each octave A than you will for each third, or fifth. (Not zero, but less.) So, a neural system that associates tones by octaves will be better able to discriminate tones than one which relies on other harmonic pairs. In other words, if I was categorizing by every possible harmonic, I would have too much similarity among all the notes, and not enough differences to discriminate. If I receive A, and sympathetic vibrations of the octave below it, and the octave above, I know from learned experience what that note is. If I receive thirds and fifths, the reinforcement is less in magnitude, and since many other beat frequencies will be received as well, it serves my need to discriminate tone better if my brain ignores all but one set of harmonics, the integer multiples being the simplest. So, long ago species with the need to discriminate tone developed brain structures that accommodated the process of intensifying integer harmonics, and the octave was born. Biology manages to accommodate physics. Tris [/QUOTE] Whaddaya tryin’ to do, address the OP or somethin’? 😃 (Not that other’s haven’t, I’m just joking about how far from the OP the thread has come…) Thanks for that post. -FrL- ---
**Author:** ![Triskadecamus](https://avatars.discourse-cdn.com/v4/letter/t/b19c9b/32.png) [@Triskadecamus](https://boards.straightdope.com/u/Triskadecamus)\ **Post date:** [March 14, 2007, 11:56pm UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/154 "2007-03-14T23:56:35Z")
Damn. There is a great pun there somewhere about seeing the light and hearing the music, but I just can’t quite get it. Tris ---
**Author:** ![garygnu](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garygnu/32/2924_2.png) [@garygnu](https://boards.straightdope.com/u/garygnu)\ **Post date:** [March 15, 2007, 2:06am UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/155 "2007-03-15T02:06:49Z")
[QUOTE=Triskadecamus] Damn. There is a great pun there somewhere about seeing the light and hearing the music, but I just can’t quite get it. Tris [/QUOTE] There’s always [this](http://en.wikipedia.org/wiki/Synesthesia#Music_.E2.86.92_color_synesthesia). ---
**Author:** ![RaftPeople](https://avatars.discourse-cdn.com/v4/letter/r/6f9a4e/32.png) [@RaftPeople](https://boards.straightdope.com/u/RaftPeople)\ **Post date:** [March 15, 2007, 3:51am UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/156 "2007-03-15T03:51:17Z")
[QUOTE=garygnu] There’s always [this](http://en.wikipedia.org/wiki/Synesthesia#Music_.E2.86.92_color_synesthesia). [/QUOTE] **BrainWreck** , you should read the link. I say this because of the following post you made: “But still, this does not mean they are viewing an altered perception of the world… just a restricted perception. I maintain the contrary case to be effectively **impossible** … that an animal would perceive fifths are more similar than octaves, or thirds more similar than fifths… because it contradicts the principles of physics, physiology, and evolution. If you want to consider the argument from ignorance and talk about unknown definitions of evolution, be my guest.” While the link is not referring to sound, it is referring to (literally) viewing an altered perception of the world. ---
**Author:** ![Triskadecamus](https://avatars.discourse-cdn.com/v4/letter/t/b19c9b/32.png) [@Triskadecamus](https://boards.straightdope.com/u/Triskadecamus)\ **Post date:** [March 15, 2007, 5:10am UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/157 "2007-03-15T05:10:20Z")
[QUOTE=garygnu] There’s always [this](http://en.wikipedia.org/wiki/Synesthesia#Music_.E2.86.92_color_synesthesia). [/QUOTE] I’m sorry. That was not all that great a pun. Tris ---
**Author:** ![HMS\_Irruncible](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hms_irruncible/32/7394_2.png) [@HMS\_Irruncible](https://boards.straightdope.com/u/HMS_Irruncible)\ **Post date:** [March 15, 2007, 1:23pm UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/158 "2007-03-15T13:23:34Z")
[QUOTE=RaftPeople] **BrainWreck** , you should read the link. While the link is not referring to sound, it is referring to (literally) viewing an altered perception of the world. [/QUOTE] Not only will I read it but I’ll quote it: > [@](#): > > Like grapheme → color synesthesia, there is rarely agreement amongst synesthetes that a given tone will be a certain color, but individuals are internally consistent. It’s not just some willy-nilly reassignment of perception, there is an ordered consistency within the individual. What I keep pointing out is that regarding octaves as less similar than other intervals would be inconsistent, that the appearance of such sensory inconsistency would be so highly unfavorable and virtually unsurvivable as to be effectively impossible. ---
**Author:** ![RaftPeople](https://avatars.discourse-cdn.com/v4/letter/r/6f9a4e/32.png) [@RaftPeople](https://boards.straightdope.com/u/RaftPeople)\ **Post date:** [March 15, 2007, 2:35pm UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/159 "2007-03-15T14:35:07Z")
[QUOTE=Brain Wreck] It’s not just some willy-nilly reassignment of perception, there is an ordered consistency within the individual. What I keep pointing out is that regarding octaves as less similar than other intervals would be inconsistent, that the appearance of such sensory inconsistency would be so highly unfavorable and virtually unsurvivable as to be effectively impossible. [/QUOTE] First Point You stated that it is essentially impossible to develop an altered view of reality, but the link is an example of an altered view of reality, seeing color patterns where they do not exist. Second and More Interesting Point You state that this development wrt hearing “would be so unfavorable…”, which was the OP’s question (“Wouldn’t we be as fit if we heard fifths as more similar than octaves…”) So you have stated your opinion, now you need to back it up with facts. Just because you say it’s unfavorable does not make it unfavorable under all conditions. It’s entirely possible that hearing octaves as similar, while a side effect of our physiology, is not valuable. It’s also possible it’s very valuable. Do you have any data, other than your own personal opinion to support the following 2 positions that you are presenting: 1. Hearing octaves as similar is or was valuable 2. Hearing fifths as similar while ignoring the similarity of octaves could not possibly be valuable and therefore would never arise ---
**Author:** ![Frylock](https://avatars.discourse-cdn.com/v4/letter/f/ce7236/32.png) [@Frylock](https://boards.straightdope.com/u/Frylock)\ **Post date:** [March 15, 2007, 3:21pm UTC](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567/160 "2007-03-15T15:21:46Z")
[QUOTE=Brain Wreck] Not only will I read it but I’ll quote it: It’s not just some willy-nilly reassignment of perception, there is an ordered consistency within the individual. What I keep pointing out is that regarding octaves as less similar than other intervals would be inconsistent, that the appearance of such sensory inconsistency would be so highly unfavorable and virtually unsurvivable as to be effectively impossible. [/QUOTE] As RaftPeople has now responded, I wanted to say something about this as well. You misunderstood the text you quoted. By saying the synesthetic individuals are “internally consistent,” it just means to say that the person continues to give the same synesthetic judgments over her entire lifetime. This is in contrast to the fact that different synesthetes will give different judgments than each other. A single synesthete always gives the same judgment. She is “internally consistent.” But two different synesthetes will not agree on their judgments. The fact that the judgments differ from person to person shows that synesthesia _does_ involve a willy-nilly reassignment of perception. The article does not claim there is an “ordered consistency” within the individual, only that the individual’s judgments remain “consistent” over time. He doesn’t call the letter E blue one day, and red the next. -FrL- [Previous page](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567.md?page=7) [Next page](https://boards.straightdope.com/t/evolutionary-advantage-to-hearing-octaves-as-the-same/395567.md?page=9)