Did our brains evolve to understand quantum mechanics?

[Pythagorean]

I think what you're failing to observe is that the ability to throw a spear accurately is a completely different kind of activity than intellectually sorting out and articulating the 3 Laws

This is interesting, because this is what I think you're failing to observe:

"Intellectually sorting out and articulating the 3 laws". That is not intuition. You're conflating cognitive concepts here. Intuition is not knowledge, it's an ability to acquire knowledge; it's parallel to reason and deduction (other abilities used to acquire knowledge that you seem to be confusing with intuition when you say "intellectually sorting" and "articulating"). Look at the definition:

"the ability to understand something immediately, without the need for conscious reasoning."

https://www.google.ca/search?q=define:+intuition&oq=define:+intuition

or the psychology-motivated wiki (which restates the above definition and adds:)

"Intuition provides us with views, understandings, judgements, or beliefs that we cannot in every case empirically verify or rationally justify."

http://en.wikipedia.org/wiki/Intuition_(psychology )

Whereas... throwing a spear is something arises without the need for conscious reasoning:

A caveman didn't need to formulate the range law to predict his spear
He didn't need to find the law of gravity to throw the spear
He didn't need to find the cohesion force of animal flesh or formulate pressure laws to show that a spearhead would penetrate it

A caveman knows about the laws governing spear flight "without the need for conscious reasoning".

(Also, I never said we evolved to understand classical mechanics in the sense that it was selected for, all I'm saying is that lots of hardware underlying aspects of classical mechanics were selected for. Please see my first post on page 1; I've re-introduced it in my response to atty below. Once again, I repeat, it's the underlying framework: space and particles.)

 

[Pythagorean]

@atyy, was their a particular paragraph from that paper you had in mind? They use the word puzzle, but in a meta-context only. Other than that they conclude we may have evolved to figure out stuff about our world.. which applies equally to QM as CM.

The Bohmian interpretation makes QM as intuitive as classical statistical mechanics. And yes, classical mechanics is not intuitive - there was Aristotelian physics for a long time before that. I think this is in the spirit of what zoobyshoe has been saying.

"Aristotle’s physics bad reputation is undeserved, and leads to diffused ignorance: think for a moment, do you really believe that bodies of different weight fall at the same speed? Why don’t you just try: take a coin and piece of paper and let them fall. Do they fall at the same speed? Aristotle never claimed that bodies fall at different speed if we take away the air. He was interested in the speed of real bodies falling in our real world, where air is present. It is curious to read everywhere “Why didn’t Aristotle do the actual experiment?â€. I do not know if he did, but I know that if he did observation would have confirmed his theory." http://arxiv.org/abs/1312.4057

You have to qualify. When you say "classical mechanics is not intuitive" that could mean anything. Do you mean "all", "there exists", "most". I would even agree that most specific laws, theorems, etc, in classical mechanics is not intuitive. But that still doesn't conflict with my original point in this thread (see page 1):

"I think the basic point of the OP quote is just that determinism and continuity (concepts of classical physics) are extremely intuitive to humans, and have (arguably) been selected for as part of motion prediction and spatial navigation. There probably aren't many predator or prey that behave like quantum particles."

As I've said many times, it's the underlying framework that's intuitive: determinism, continuity, locality (and apparently even cohesion and solidity). probability (statistical mechanics) is not intuitive to students at all. People struggle even with the Monty Hall problem. In fact, the probabilistic nature of QM is one of the things that makes it intuitive. People tend to interpret events in the world as if they were deterministic.

 

[atyy]

@atyy, was their a particular paragraph from that paper you had in mind? They use the word puzzle, but in a meta-context only. Other than that they conclude we may have evolved to figure out stuff about our world.. which applies equally to QM as CM.

So you do agree with zoobyshoe's point?

The remaining debate about whether classical or quantum mechanics is more intuitive on what aspects seems like hairsplitting then.

 

[Pythagorean]

I don't know what point you're referring to. When Zooby made puzzle-solving about hunting as well as QM then it's so all-inclusive that it's not meaningful discussion really. And I wasn't agreeing with the article, just stating their conclusion for clarification of your point. I provided several sources from several different disciplines that focused on a clear point.

I don't think it's hairsplitting, I think the wealth of evidence I've provided are all about intuitions that are pervasive in CM and directly contradict much of QM.

 

[atyy]

I don't know what point you're referring to. When Zooby made puzzle-solving about hunting as well as QM then it's so all-inclusive that it's not meaningful discussion really. And I wasn't agreeing with the article, just stating their conclusion for clarification of your point. I provided several sources from several different disciplines that focused on a clear point.

I don't think it's hairsplitting, I think the wealth of evidence I've provided are all about intuitions that are pervasive in CM and directly contradict much of QM.

As I understand, zoobyshoe's (and others') point was that even spear throwing is not intuitive, and that the ability to learn unintuitive things like throwing a stone, a spear, classical mechanics and quantum mechanics could be selected for. Certain aspects of each may be more or less intuitive, and even then the intuitive aspects may vary from person to person, and not be hardwired, let alone specifically selected for, into human beings with any reliability. At this point in my life, I don't consider quantum mechanics more unintuitive than classical mechanics, but I do still feel Newton's first law is unintuitive.

A basic problem with all your sources is that they do not show that the things were not learnt, but were selected for. I agree that the opposite - the ability to learn unintuitive things has been selected for - has not been demonstrated either. But it remains a possibility, and seems to me would undermine Krauss's point.

 

[atyy]

Here for example, is an alternative to Krauss's comments (I realize this is taking them too seriously, but anyway, the whole thread is.)

How about: human beings learn. From an early age, we learn intuitions that are more consonant with some aspects of classical mechanics. Consequently, when we are exposed to quantum mechanics in the Copenhagen interpretation at a later age, some aspects seem unintuitive given the intuitions we learned at an earlier age.

 

[Pythagorean]

I'm just going to summarize my argument here and I'm done. I feel like I've been rehashing old points for a while now. Sometimes it seems like semantics and hair-splitting, but I don't think we're going to advance the conversation past where it is.

Summary

interpreation of OP Krauss: (my opening post in this thread)

I think the basic point of the OP quote is just that determinism and continuity (concepts of classical physics) are extremely intuitive to humans, and have (arguably) been selected for as part of motion prediction and spatial navigation. There probably aren't many predator or prey that behave like quantum particles.

My more formal argument (evidence in post)
https://www.physicsforums.com/showpost.php?p=4607304&postcount=35

P1) Spatial reasoning is selected for (and possibly other underlying aspects of classical physics if you consider the infant physics article as evidence)

P2) This spatial (and physical) intuition underlies the abstract reasoning that makes up classical mechanics (i.e. the the intuition upon which we built classical physics).

P3) many of the intuitive concepts underlying CM are opposite of observations in QM (particles are not localized, they can tunnel through walls, lack of continuity in state transitions, identical particles)

I would also just note that much of the language and perspectives we adopted for classical physics are used in quantum physics. Classical physics is a framework for quantum mechanics, but we had to make major adjustments that violated some of our most "sacred" aspects of classical physics because classical physics is just a fundamental part of our intuition that we think it describes our universe. But it seems to be wrong, and QM seems to be right.

To me, this suggests that our classical physics has more to do with our intuition than it does with reality.

 

[Pythagorean]

As I understand, zoobyshoe's (and others') point was that even spear throwing is not intuitive, and that the ability to learn unintuitive things like throwing a stone, a spear, classical mechanics and quantum mechanics could be selected for. Certain aspects of each may be more or less intuitive, and even then the intuitive aspects may vary from person to person, and not be hardwired, let alone specifically selected for, into human beings with any reliability. At this point in my life, I don't consider quantum mechanics more unintuitive than classical mechanics, but I do still feel Newton's first law is unintuitive.

A basic problem with all your sources is that they do not show that the things were not learnt, but were selected for. I agree that the opposite - the ability to learn unintuitive things has been selected for - has not been demonstrated either. But it remains a possibility, and seems to me would undermine Krauss's point.

I'll respond to this since it was made before my announcement, but it seems like semantics and/or strawman really: I didn't say all of these things "were not learned but were selected for". I am saying that spatial reasoning was selected for (and arguably other physical notions) and that they made learning spear throwing easier (P1 leads to P2 in my review above).

Again, the formal definition of intuition "the ability to acquire knowledge without reasoning" (i.e. learn). Zooby's strawman is different than yours. He seems to think I'm saying that "we formulated classical physics without reasoning". Or that "every outcome of classical physics is accurately predicted by human intuition". Further, atyy, your post #66 isn't in conflict with my point. There is no dichotomy between learning and innate: things can be more one or the other or they can be somewhere in between. I believe Yggg and I have come to agreement that they're somewhere in between. Also see "ode to learning" in my linked post above to my formal argument and reread my opening post (also included in my post above).

I could easily be misinterpreting points, too. Maybe if we all take a break and read the thread later we'll be able to read original arguments more clearly without whatever presumptions we have in our heads that cause mis-communication.

Thanks to all for the discussion.

 

[atyy]

I'll respond to this since it was made before my announcement, but it seems like semantics and/or strawman really: I didn't say all of these things "were not learned but were selected for". I am saying that spatial reasoning was selected for (and arguably other physical notions) and that they made learning spear throwing easier (P1 leads to P2 in my review above).

Again, the formal definition of intuition "the ability to acquire knowledge without reasoning" (i.e. learn). Zooby's strawman is different than yours. He seems to think I'm saying that "we formulated classical physics without reasoning". Or that "every outcome of classical physics is accurately predicted by human intuition". Further, atyy, your post #66 isn't in conflict with my point. There is no dichotomy between learning and innate: things can be more one or the other or they can be somewhere in between. I believe Yggg and I have come to agreement that they're somewhere in between. Also see "ode to learning" in my linked post above to my formal argument and reread my opening post (also included in my post above).

I could easily be misinterpreting points, too. Maybe if we all take a break and read the thread later we'll be able to read original arguments more clearly without whatever presumptions we have in our heads that cause mis-communication.

Thanks to all for the discussion.

I'm not really responding to your OP - I'm thinking largely of this post, where the researchers wish to support that some knowledge is innate.

http://munews.missouri.edu/news-rel...uitive-physics”-knowledge-says-mu-researcher/

In the first place, the supposed innate knowledge is very weak. For example http://www.ncbi.nlm.nih.gov/pubmed/11340923 "The results indicated that at this age infants are able to reason about height in occlusion but not containment events. Experiment 3 showed that this latter ability does not emerge until about 7.5 months of age. The marked discrepancy in infants' reasoning about height in occlusion and containment events suggests that infants sort events into distinct categories, and acquire separate rules for each category." I couldn't get that free, but this seems to provide some details http://internal.psychology.illinois.edu/infantlab/articles/baillargeon2004b.pdf.pdf

So in fact, a 2.5 month-old infant's view of the world is very unintuitive to an adult, which would be more like that of a 7.5 month old infant.

Secpnd, there appears to be some controversy, eg. http://www.ncbi.nlm.nih.gov/pubmed/16637762 about what sort of innate knowledge these experiments test. "The authors use the model to simulate a set of influential experiments by R. Baillargeon (1986, 1987a, 1987b) using the well-known "drawbridge" paradigm. The dynamic field model provides a coherent explanation without invoking infant object knowledge."

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2605404/ gives some references which may be interesting to look at "Some researchers claim that the relevant data can be explained without appeal to “initial knowledge†of the world, based on familiarity preferences (e.g. Bogartz et al., 1997; Cohen and Marks, 2002; Haith, 1998). Others have attempted to rebut these arguments, arguing that these interpretations cannot account for the full array of data in each domain (e.g. Baillargeon, 1999; Carey, 2002; Spelke, 1998; Wynn, 2002)."

 

[Enigman]

Okay, I skimmed through the thread...and got lost.
Intuition as defined in #61

"the ability to understand something immediately, without the need for conscious reasoning."
"Intuition provides us with views, understandings, judgements, or beliefs that we cannot in every case empirically verify or rationally justify."

A few questions :
----
1. Does the definition necessarily preclude prior knowledge and or experience?
2. Given enough knowledge and experience in a subject matter would one become more intuitive with regard to that?
(- If yes, the experience we have with classical mechanic approximations is much greater than QM which means Classical mechanics or at least its basic applications are more intuitive than of QM)
---
Coming back to the absent OP's question-

We evolved as human beings a few million years ago on the Savanna in Africa and we evolved to escape tigers, or lions, or predators. You know, how to throw a rock or a spear or how to find a cave and we didn't evolve to understand quantum mechanics.

Assuming 'evolve to' means 'evolutionarily selected for'
---
I don't think that the understanding QM has ever been a factor in evolution so yes, as far as the bare-bones go it seems justified.
Extrapolating it however to all problem solving involved would be foolish. Evolution has enabled us to acquire the intelligence to understand QM. (#23Ygg)
In #25

The intuition we (and most mammals) start with allowed us to track prey and avoid predators, to know our bodies position in space, to predict trajectories, to judge depth so we don't walk off cliffs. We have great spatial intuition in the classical physics sense. These are readily available for throwing a rock or spear [...]

'Intuition we start with'
-that's a bit vague. Do you mean that its innate ? Anyway the citations given in #35 seem to refer to spatial reasoning rather than intuition, innate or otherwise.

QM concepts like nonlocality, indistinguishability, superposition of states... intuition for such concepts wouldn't have had any usefulness in reproduction in the 99.9% of human history.

Sit-coms tell me that it is a liability to one's reproductive prospects...

 

[zoobyshoe]

Zooby's strawman is different than yours. He seems to think I'm saying that "we formulated classical physics without reasoning". Or that "every outcome of classical physics is accurately predicted by human intuition".

Everything you've said indicates you think it was much easier than I know it actually was, and that QM was much harder than it actually was.

 

[Ygggdrasil]

To try to summarive my current views on the subject:
1) The human brain has evolved mechanisms for spatial reasoning and pattern recognition, but is not born with the physical intuitions dicussed in the "Physics for Infants" article posted by Pythagorean (#40).
2) The physical intuitions come about by the interaction of the spatial reasoning and pattern recognition mechanisms with a world that obeys the laws of classical mechanics (i.e. via learning). This seems to be supported by some of the evidence posted by atyy suggesting that these intuitions develop over time (#69).

One reason I favor this model is by analogy to the way our visual processing circuitry develops. While it might make sense for the way our eyes are wired to the brain to be pre-determined by genetics, the wiring actually occurs in response to simulation of the eyes by the environment (as shown by the classic monocular deprivation experiments done by Hubel and Wiesel). Of course, certain genetic factors influence the process (for example, certain neurotrophic factors define a specific critical period during which the wiring can occur), but this is a nice example that clearly demonstrates how neural circuitry develops in response an individual's experiences.

Of course, this model essentially specifies the inevitable development of physical intuition because no infant will experience a world not governed by classical mechanics. So, in this sense, you can say physical intuitions are pre-determined. Of course, it would be interesting (but highly unethical) to test whether raising an infant in some virtual reality that presents different physical laws could alter the learned physical intuitions of the child or whether the infant still develops innate physical intuitions consistent with the real world. Perhaps such experiments might be possible using virutal reality systems for studying mice (for example http://www.nature.com/nature/journal/v461/n7266/full/nature08499.html).

 

[atyy]

To try to summarive my current views on the subject:
1) The human brain has evolved mechanisms for spatial reasoning and pattern recognition, but is not born with the physical intuitions dicussed in the "Physics for Infants" article posted by Pythagorean (#40).
2) The physical intuitions come about by the interaction of the spatial reasoning and pattern recognition mechanisms with a world that obeys the laws of classical mechanics (i.e. via learning). This seems to be supported by some of the evidence posted by atyy suggesting that these intuitions develop over time (#69).

One reason I favor this model is by analogy to the way our visual processing circuitry develops. While it might make sense for the way our eyes are wired to the brain to be pre-determined by genetics, the wiring actually occurs in response to simulation of the eyes by the environment (as shown by the classic monocular deprivation experiments done by Hubel and Wiesel). Of course, certain genetic factors influence the process (for example, certain neurotrophic factors define a specific critical period during which the wiring can occur), but this is a nice example that clearly demonstrates how neural circuitry develops in response an individual's experiences.

Of course, this model essentially specifies the inevitable development of physical intuition because no infant will experience a world not governed by classical mechanics. So, in this sense, you can say physical intuitions are pre-determined. Of course, it would be interesting (but highly unethical) to test whether raising an infant in some virtual reality that presents different physical laws could alter the learned physical intuitions of the child or whether the infant still develops innate physical intuitions consistent with the real world. Perhaps such experiments might be possible using virutal reality systems for studying mice (for example http://www.nature.com/nature/journal/v461/n7266/full/nature08499.html).

I'm not sure the experiment in humans would be unethical. In the Copenhagen* interpretation, the world is always divided into classical and quantum, so classical reality is needed for quantum mechanics. Since only a part of the world needs to be quantum, I think one need not remove all classical reality to see if one can raise an infant to find quantum-like phenomena intuitive by 2.5 months of age. Perhaps one could raise some infants in the presence of quantum billiards http://www.physics.princeton.edu/~steinh/ph115/TompkinsQuantumBilliards.pdf

*By Copenhagen, I just mean some workaday interpretation like that in Landau and Lifshitz's quantum mechanics textbook. Also, I personally don't think quantum mechanics is unintuitive - unless we adopt many-worlds)

Incidentally, Wang and Baillargeon seem to have some arguments against the suggestion I made in #69, which Ygggdrasil quotes above, that the data suggest that infants' intuitions change over time. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3351384/

 

[zoobyshoe]

I agree that the opposite - the ability to learn unintuitive things has been selected for - has not been demonstrated either. But it remains a possibility, and seems to me would undermine Krauss's point.

What would be the possible alternatives to it's having been selected for?


I'm also thinking now I disagree that we evolved to escape predators. Of all the wildlife on the Savannah, I think Lucy would have been the easiest target. As a lion, I'd pick a hominid over a gazelle any day.

 

[Simon Bridge]

There is a grey area in what gets "selected" ... a trait may be a side-effect of something else being directly selected. The side effect turns out to be easy to pass on so comes to dominate a population. Was that selected for? Perhaps we could say that it is indirectly selected for?

Certainly part of our evolution would have involved predator escape and avoidance.
That is pretty much the case for everything alive.

You have to be careful about your metric. Individual humans are pretty vulnerable in the wild - but we evolved as social animals and a bunch of humans can be quite formidable. If chasing a herd of gazelles quickly reveals a weaker one while chasing humans gets rocks thrown at you, which do you pick?

However, there are quite a lot of things affecting evolution.
If we accept that big brains got emphasized as a secondary sexual characteristic - as in peacocks tails - then you need to be able to show them off ... just having a bighead is no guarantee of lots of brains.
So you get jokes, puns, art, ... inventiveness (display inventions)... inquisitiveness (find stuff out)... and the ability to grok stuff others don't. That would include the ability to learn un- and counter-intuitive things.

Perhaps the ability to learn something counter-intuitive is a form of display behavior.
Teaching - sharing information - could also be a form of preening.

Note: in animals with sexual-selected characteristics, the male tends to have the display form and the female the discrimination form or the trait. Peacocks have the big tails and the ability to stand them up while females have the ability to assess who has the best tail. For big brains as the trait - this means that female humans need to be intelligent too - to judge who has the best brain and who's just a nut - but their intelligence needs to be of a different kind: more critical.

But that's if we accept the premise - and would be an alternative to direct selection.
It would be tricky to demonstrate.

Everything is indirectly selected for - but then the term stops meaning anything.

 

[atyy]

What would be the possible alternatives to it's having been selected for?I'm also thinking now I disagree that we evolved to escape predators. Of all the wildlife on the Savannah, I think Lucy would have been the easiest target. As a lion, I'd pick a hominid over a gazelle any day.

By "selected for" I and most people usually mean "natural selection". So maybe the ability to learn unintuitive things came from random drift or sexual selection.

Also, along the lines of Simon Bridge's post above this one, it could be a spandrel. Actually, that seems to be Coyne's reading of Pinker's proposal. http://whyevolutionistrue.wordpress.com/2010/05/31/did-humans-evolve-to-fill-a-cognitive-niche/ On a quick reading of http://www.pnas.org/content/early/2010/05/04/0914630107.full.pdf+html , I'm not sure Coyne is right on that point. Pinker writes "In this conception, the brain’s ability to carry out metaphorical abstraction did not evolve to coin metaphors in language, but to multiply the opportunities for cognitive inference in domains other than those for which a cognitive model was originally adapted." which seems pretty close to what you and Ygggdrasil have been suggesting.

 

[zoobyshoe]

It seems that, whichever mechanism accounts for the origin of a new trait, it being advantageous to reproduction would assure it getting passed on and reinforced and successive generations would exhibit the new trait more and more.

"Puzzle-solving," which is certainly a manifestation of intelligence (a word some might find less vague, more acceptable to discuss as a heritable thing), is such that we have literally taken over the planet and are now, without question, the most successful life form. I can't see anyone mounting a credible argument for puzzle-solving not being advantageous.

On the point of us not being hardwired for anything in particular at birth, merely possessed of a massive amount of plastic neurons that could be taught a huge variety of things, I would suspect that the important selection was for those flexible neurons. That would have been made in relatively primitive creatures that are long gone, but which had the advantage over whatever came before them of being able to learn to change according to the demands of their environment. A creature born completely hardwired, if such ever existed, would inevitably be foiled by slight changes and could only exist in a really stable environment.

So, the greater the ability to learn, the greater the options for everything necessary: escape, finding food, finding a mate, etc. The advantage humans have wouldn't be puzzle-solving per se, but the comparatively much more massive capacity for it. All kinds of animals are obviously puzzle solving. Our difference is we do it much better.

What do you think?

 

[zoobyshoe]

You have to be careful about your metric. Individual humans are pretty vulnerable in the wild - but we evolved as social animals and a bunch of humans can be quite formidable. If chasing a herd of gazelles quickly reveals a weaker one while chasing humans gets rocks thrown at you, which do you pick?

This is a good point. However, lions and cheetahs usually hunt in pairs or groups of three (if we can believe Cat Diary on Animal Planet). Lucy's people were pretty small compared to modern Africans, and Lucy's predators were a lot larger than modern lions, wolves, etc.

Now, pygmies kill elephants by being clever. They are forest dwellers and the elephants generally stick to well worn elephant trails. The pygmies pull entire logs up into the trees, and drop them on the elephants as they pass beneath. In this way, they avoid putting themselves in too much danger.

So, maybe it's conceivable hominids were clever enough to engineer ways to lure and kill the local population of predators, creating a tentative safe zone around their camps. In any event, I just don't see them thriving if every food foraging expedition meant a life or death encounter with predators. As far as I know, apes never live anywhere where they aren't the biggest thing around. The fact hominids could walk upright and run never struck me as all they'd need to leave the forest and live out in the open.

 

[Enigman]

It seems that, whichever mechanism accounts for the origin of a new trait, it being advantageous to reproduction would assure it getting passed on and reinforced and successive generations would exhibit the new trait more and more.

No not necessarily...genetic drift can get rid of some traits just due to chance alone.

 

[zoobyshoe]

No not necessarily...genetic drift can get rid of some traits just due to chance alone.

So, you're suggesting something like this might happen:

A new and advantageous trait appears in a population. But, before those with the trait can fully supplant those without, some freak accident kills off all those with the trait. (?)

 

[Enigman]

So, you're suggesting something like this might happen:

A new and advantageous trait appears in a population. But, before those with the trait can fully supplant those without, some freak accident kills off all those with the trait. (?)

Yes, anything random that would stop the traits from being passed on. From freak accidents to bad luck in finding a mate to linkage with an allele which is disadvantageous.
(I grow wings and get smashed with an airplane or go celibate or appearance of wings comes with disappearance of my brains...no kids, no winged humans.)
EDIT: I think linkage with other alleles is genetic draft rather than drift.

 

[zoobyshoe]

Yes, anything random that would stop the traits from being passed on. From freak accidents to bad luck in finding a mate to linkage with an allele which is disadvantageous.
(I grow wings and get smashed with an airplane or go celibate or appearance of wings comes with disappearance of my brains...no kids, no winged humans.)
EDIT: I think linkage with other alleles is genetic draft rather than drift.

OK, that could happen. Barring that, are there other important obstacles to a really advantageous trait becoming more and more prevalent in succeeding generations?

 

[zoobyshoe]

By "selected for" I and most people usually mean "natural selection". So maybe the ability to learn unintuitive things came from random drift or sexual selection.

The wiki describes sexual selection as a "mode" of natural selection. For whatever that's worth.

Also, along the lines of Simon Bridge's post above this one, it could be a spandrel.

If this were the case then we'd have a situation where a spandrel seems to have taken off on its own right and eclipsed the thing it was originally a mere byproduct of. The original thing could remain as important as it originally was, but the spandrel would outclass it. Sort of thing.

 

[atyy]

The wiki describes sexual selection as a "mode" of natural selection. For whatever that's worth.

Yes, I realize some say that, eg. http://evolution.berkeley.edu/evosite/evo101/IIIE3Sexualselection.shtml[/URL] . A different point of view is presented in [url]http://www.nature.com/scitable/knowledge/library/sexual-selection-13255240[/url] .

[quote="zoobyshoe, post: 4611334"]If this were the case then we'd have a situation where a spandrel seems to have taken off on its own right and eclipsed the thing it was originally a mere byproduct of. The original thing could remain as important as it originally was, but the spandrel would outclass it. Sort of thing.[/QUOTE]

The basic idea you have seems reasonable to me, of course - I was brainwashed by my parents to believe that plasticity can do anything:p And yes, it does seem an "advantageous" trait that could be "selected for". In [url]http://whyevolutionistrue.wordpress.com/2013/07/07/a-defense-of-evolutionary-psychology-mostly-by-steve-pinker/[/url] Coyne makes, I think, a point very similar to yours ""developmental plasticity" does not stand as a dichotomous alternative to "evolved features." Our developmental plasticity is to a large extent the product of evolution: our ability to learn language, our tendency to defer to authorities when we’re children, our learned socialization—those are all features almost certainly instilled into our brains by natural selection as a way to promote behavioral flexibility in that most flexible of mammals. " But to make it scientific, I would usually ask for a mathematical framework and definition of the terms (that may be a bit much), and predictions which could test and potentially falsify the theory.

Incidentally, it's not obvious to me human beings are the most successful species. How about cockroaches?

 

[zoobyshoe]

Yes, I realize some say that, eg. http://evolution.berkeley.edu/evosite/evo101/IIIE3Sexualselection.shtml[/URL] . A different point of view is presented in [url]http://www.nature.com/scitable/knowledge/library/sexual-selection-13255240[/url] .[/QUOTE]
I'd have to agree with the former. I don't see an important difference between a percentage of the population with certain traits dying out because they can't hack the physical environment or dying out because other members of their own sex prevent their access to the opposite, or because the opposite sex won't have them. All these things are equally "natural," I'd say. Not that it isn't important to observe the differences between one mechanism and the other. In the same way, drift and spandrels strike me as "natural." If I were writing up the terminology, I'd say there were 4 distinct modes of Natural Selection.
[QUOTE]But to make it scientific, I would usually ask for a mathematical framework and definition of the terms (that may be a bit much), and predictions which could test and potentially falsify the theory.[/QUOTE]
Dude, I'm like, doing "Intuitive Biology" here. What's not scientific?
[QUOTE]Incidentally, it's not obvious to me human beings are the most successful species. How about cockroaches?[/QUOTE]
Cockroaches didn't land on the moon. More than any other species we have the ability to shape our environment to make up for the fact we're not suited to it, and even sustain it in miniature in remote outposts: space, antarctica, the middle of the ocean. If the cockroach environment shifts outside the cockroach parameters, they're toast. As Ygggdrasil pointed out, human babies are quite delicate for years. In the last 4.0 X 10[SUP]4[/SUP] years we've pretty much reshaped the world to make it comfortable for human babies. And, among other things, we've killed a lot of cockroaches to do that.

You could argue that's only a short term glitch in the millions of years of cockroach history and you might be right. They could be the tortoise and we the hare in that regard. What I see as our real evolutionary lottery win is the comparatively massive magnitude of our consciousness. A thing which makes the statement, "We didn't evolve to understand QM," fundamentally wrong.

 

[Simon Bridge]

It seems that, whichever mechanism accounts for the origin of a new trait, it being advantageous to reproduction would assure it getting passed on and reinforced and successive generations would exhibit the new trait more and more.

Nothing is assured. The only way a trait is assured of surviving is if it certain of being passed on - such "traits" need not even be expressed for this to happen.

"Puzzle-solving," which is certainly a manifestation of intelligence (a word some might find less vague, more acceptable to discuss as a heritable thing), is such that we have literally taken over the planet and are now, without question, the most successful life form. I can't see anyone mounting a credible argument for puzzle-solving not being advantageous.

It's the amount of puzzle-solving ability in humans that causes comment - even other species notice that humans can be good to have around (or bad - depends). If this level of puzzle solving were so advantageous, then everyone would have it - cats, dogs, birds ... so why not if there is no intrinsic disadvantage to be balanced?

On the point of us not being hardwired for anything in particular at birth, merely possessed of a massive amount of plastic neurons that could be taught a huge variety of things, I would suspect that the important selection was for those flexible neurons. That would have been made in relatively primitive creatures that are long gone, but which had the advantage over whatever came before them of being able to learn to change according to the demands of their environment. A creature born completely hardwired, if such ever existed, would inevitably be foiled by slight changes and could only exist in a really stable environment.

Plankton seem to survive pretty well. When you are done feeling good about being smart - compare biomass for different species and see who is the most successful at long term survival. Insects (some) seem to have done much better so far without the big brains.

So, the greater the ability to learn, the greater the options for everything necessary: escape, finding food, finding a mate, etc. The advantage humans have wouldn't be puzzle-solving per se, but the comparatively much more massive capacity for it. All kinds of animals are obviously puzzle solving. Our difference is we do it much better.

One big thing in the puzzle-solving ability's favor is the ability to recognize other good puzzle-solvers.
This is why the sexual selection idea is so popular.

Peacock's tails hinder it's ability to escape predators and efficiently utilize food - but peacocks have them anyway. Oversize brains may not be that useless but the big-brain animals have been pretty unusual one so far.

We have not been around any where near long enough to know if these great lumps of grey meat we carry about are anything like the sort of advantage we like to think they are. They may kill us off yet.

 

[atyy]

I'd have to agree with the former. I don't see an important difference between a percentage of the population with certain traits dying out because they can't hack the physical environment or dying out because other members of their own sex prevent their access to the opposite, or because the opposite sex won't have them. All these things are equally "natural," I'd say. Not that it isn't important to observe the differences between one mechanism and the other. In the same way, drift and spandrels strike me as "natural." If I were writing up the terminology, I'd say there were 4 distinct modes of Natural Selection.

OK, I'm not sure this is completely correct, but let me try to explain the other viewpoint. If one says a peacock's tail is naturally selected for, then it is advantageous only in the sense of conferring reproductive fitness. However, there we have implicitly defined "advantageous" as "that which confers reproductive fitness", so the theory predicts nothing since we have just said that that which confers reproductive fitness confers reproductive fitness. So in general, "advantageous" in the theory of natural selection must be defined in some other way, for example, "advantageous" may be defined as that which confers long life. If we define "advantageous" in this way, since the peacock's tail makes the peacock's life shorter by attracting predators (I made that up, but let's focus on the concept here), then the peacock's tail is a disadvantage. Natural selection explains advantageous, not disadvantageous features, and hence does not explain the peacock's tail.

 

[zoobyshoe]

Nothing is assured. The only way a trait is assured of surviving is if it certain of being passed on - such "traits" need not even be expressed for this to happen.

What I understand people to be saying is that, barring genetic drift, traits will get passed on.

It's the amount of puzzle-solving ability in humans that causes comment - even other species notice that humans can be good to have around (or bad - depends). If this level of puzzle solving were so advantageous, then everyone would have it - cats, dogs, birds ... so why not if there is no intrinsic disadvantage to be balanced?

I'm assuming we won the lottery: one of the 4 change mechanisms boosted our capacity and it got passed on. The same just didn't happen to happen in cats, dogs, birds, at least never to the degree it did in humans.

Plankton seem to survive pretty well. When you are done feeling good about being smart - compare biomass for different species and see who is the most successful at long term survival. Insects (some) seem to have done much better so far without the big brains.

And atty mentioned cockroaches. In these two cases "success" would be a measure of their longevity as species, as you said. I am thinking of humans as the most successful in that we have the greatest ability to mitigate our own suffering. Most of our puzzle solving is to that end, and is made possible by the fact we're the most conscious. By which I mean, we have the best view of all scales, from macro to micro, and from past to present. And, so, we're the most able to ponder future consequences. Regardless, plankton and cockroaches might actually be happier.

One big thing in the puzzle-solving ability's favor is the ability to recognize other good puzzle-solvers.
This is why the sexual selection idea is so popular.

That makes sense. It also makes sense that it was selected as a response to a shift in environment. It's the ultimate quick change, all-environment solution. If you're not fit for the winter cold, kill a bear and wear it's coat. If you can't find a cave for your band, make an artificial one from whatever's around, even snow! If your band gets pushed to the equator, take off the bear skin and go naked. Anyway, it's conceivable to me it was selected by both mechanisms, one reinforcing the other.

We have not been around any where near long enough to know if these great lumps of grey meat we carry about are anything like the sort of advantage we like to think they are. They may kill us off yet.

I was wondering when someone would bring that up.

I think it's some sort of recognized cycle where predators become so successful they exhaust their prey supply, precipitating their own doom. The predator population dwindles almost to extinction, then the prey species recovers, and so do the predators. I'm sure you've heard of that.

That's different than us poisoning ourselves with radiation or chemicals, but if we don't kill everyone, there's a good chance will recover for another trip round the circuit. (The thing I'm currently most worried about is the super-germs we're creating by misuse of antibiotics.)

 

[zoobyshoe]

OK, I'm not sure this is completely correct, but let me try to explain the other viewpoint. If one says a peacock's tail is naturally selected for, then it is advantageous only in the sense of conferring reproductive fitness. However, there we have implicitly defined "advantageous" as "that which confers reproductive fitness", so the theory predicts nothing since we have just said that that which confers reproductive fitness confers reproductive fitness. So in general, "advantageous" in the theory of natural selection must be defined in some other way, for example, "advantageous" may be defined as that which confers long life. If we define "advantageous" in this way, since the peacock's tail makes the peacock's life shorter by attracting predators (I made that up, but let's focus on the concept here), then the peacock's tail is a disadvantage. Natural selection explains advantageous, not disadvantageous features, and hence does not explain the peacock's tail.

That's awfully byzantine. I wonder if the whole thing couldn't be simplified somehow.

 

[Simon Bridge]

OK, I'm not sure this is completely correct, but let me try to explain the other viewpoint. If one says a peacock's tail is naturally selected for, then it is advantageous only in the sense of conferring reproductive fitness. However, there we have implicitly defined "advantageous" as "that which confers reproductive fitness", so the theory predicts nothing since we have just said that that which confers reproductive fitness confers reproductive fitness. So in general, "advantageous" in the theory of natural selection must be defined in some other way, for example, "advantageous" may be defined as that which confers long life. If we define "advantageous" in this way, since the peacock's tail makes the peacock's life shorter by attracting predators (I made that up, but let's focus on the concept here), then the peacock's tail is a disadvantage. Natural selection explains advantageous, not disadvantageous features, and hence does not explain the peacock's tail.

Done well right up to the last sentence.
Natural selection best explains disadvantageous traits ... either that or a capricious and randomly cruel Designer.

It is us who defined "advantageous" - Nature does not care if an individual or a species lives or dies.

We don't need to define "advantageous" in relation to Natural selection.
You have to reference underlying mechanisms if you want things to stop sounding circular.
There are many ways a trait we would think of as disadvantageous to the organism to get favorably passed on. But when you look at it from the top down, it is hard to see the rules.
It's like cellular automata.