nhaliday + direction   55

Lateralization of brain function - Wikipedia
Language
Language functions such as grammar, vocabulary and literal meaning are typically lateralized to the left hemisphere, especially in right handed individuals.[3] While language production is left-lateralized in up to 90% of right-handers, it is more bilateral, or even right-lateralized, in approximately 50% of left-handers.[4]

Broca's area and Wernicke's area, two areas associated with the production of speech, are located in the left cerebral hemisphere for about 95% of right-handers, but about 70% of left-handers.[5]:69

Auditory and visual processing
The processing of visual and auditory stimuli, spatial manipulation, facial perception, and artistic ability are represented bilaterally.[4] Numerical estimation, comparison and online calculation depend on bilateral parietal regions[6][7] while exact calculation and fact retrieval are associated with left parietal regions, perhaps due to their ties to linguistic processing.[6][7]

...

Depression is linked with a hyperactive right hemisphere, with evidence of selective involvement in "processing negative emotions, pessimistic thoughts and unconstructive thinking styles", as well as vigilance, arousal and self-reflection, and a relatively hypoactive left hemisphere, "specifically involved in processing pleasurable experiences" and "relatively more involved in decision-making processes".

Chaos and Order; the right and left hemispheres: https://orthosphere.wordpress.com/2018/05/23/chaos-and-order-the-right-and-left-hemispheres/
In The Master and His Emissary, Iain McGilchrist writes that a creature like a bird needs two types of consciousness simultaneously. It needs to be able to focus on something specific, such as pecking at food, while it also needs to keep an eye out for predators which requires a more general awareness of environment.

These are quite different activities. The Left Hemisphere (LH) is adapted for a narrow focus. The Right Hemisphere (RH) for the broad. The brains of human beings have the same division of function.

The LH governs the right side of the body, the RH, the left side. With birds, the left eye (RH) looks for predators, the right eye (LH) focuses on food and specifics. Since danger can take many forms and is unpredictable, the RH has to be very open-minded.

The LH is for narrow focus, the explicit, the familiar, the literal, tools, mechanism/machines and the man-made. The broad focus of the RH is necessarily more vague and intuitive and handles the anomalous, novel, metaphorical, the living and organic. The LH is high resolution but narrow, the RH low resolution but broad.

The LH exhibits unrealistic optimism and self-belief. The RH has a tendency towards depression and is much more realistic about a person’s own abilities. LH has trouble following narratives because it has a poor sense of “wholes.” In art it favors flatness, abstract and conceptual art, black and white rather than color, simple geometric shapes and multiple perspectives all shoved together, e.g., cubism. Particularly RH paintings emphasize vistas with great depth of field and thus space and time,[1] emotion, figurative painting and scenes related to the life world. In music, LH likes simple, repetitive rhythms. The RH favors melody, harmony and complex rhythms.

...

Schizophrenia is a disease of extreme LH emphasis. Since empathy is RH and the ability to notice emotional nuance facially, vocally and bodily expressed, schizophrenics tend to be paranoid and are often convinced that the real people they know have been replaced by robotic imposters. This is at least partly because they lose the ability to intuit what other people are thinking and feeling – hence they seem robotic and suspicious.

Oswald Spengler’s The Decline of the West as well as McGilchrist characterize the West as awash in phenomena associated with an extreme LH emphasis. Spengler argues that Western civilization was originally much more RH (to use McGilchrist’s categories) and that all its most significant artistic (in the broadest sense) achievements were triumphs of RH accentuation.

The RH is where novel experiences and the anomalous are processed and where mathematical, and other, problems are solved. The RH is involved with the natural, the unfamiliar, the unique, emotions, the embodied, music, humor, understanding intonation and emotional nuance of speech, the metaphorical, nuance, and social relations. It has very little speech, but the RH is necessary for processing all the nonlinguistic aspects of speaking, including body language. Understanding what someone means by vocal inflection and facial expressions is an intuitive RH process rather than explicit.

...

RH is very much the center of lived experience; of the life world with all its depth and richness. The RH is “the master” from the title of McGilchrist’s book. The LH ought to be no more than the emissary; the valued servant of the RH. However, in the last few centuries, the LH, which has tyrannical tendencies, has tried to become the master. The LH is where the ego is predominantly located. In split brain patients where the LH and the RH are surgically divided (this is done sometimes in the case of epileptic patients) one hand will sometimes fight with the other. In one man’s case, one hand would reach out to hug his wife while the other pushed her away. One hand reached for one shirt, the other another shirt. Or a patient will be driving a car and one hand will try to turn the steering wheel in the opposite direction. In these cases, the “naughty” hand is usually the left hand (RH), while the patient tends to identify herself with the right hand governed by the LH. The two hemispheres have quite different personalities.

The connection between LH and ego can also be seen in the fact that the LH is competitive, contentious, and agonistic. It wants to win. It is the part of you that hates to lose arguments.

Using the metaphor of Chaos and Order, the RH deals with Chaos – the unknown, the unfamiliar, the implicit, the emotional, the dark, danger, mystery. The LH is connected with Order – the known, the familiar, the rule-driven, the explicit, and light of day. Learning something means to take something unfamiliar and making it familiar. Since the RH deals with the novel, it is the problem-solving part. Once understood, the results are dealt with by the LH. When learning a new piece on the piano, the RH is involved. Once mastered, the result becomes a LH affair. The muscle memory developed by repetition is processed by the LH. If errors are made, the activity returns to the RH to figure out what went wrong; the activity is repeated until the correct muscle memory is developed in which case it becomes part of the familiar LH.

Science is an attempt to find Order. It would not be necessary if people lived in an entirely orderly, explicit, known world. The lived context of science implies Chaos. Theories are reductive and simplifying and help to pick out salient features of a phenomenon. They are always partial truths, though some are more partial than others. The alternative to a certain level of reductionism or partialness would be to simply reproduce the world which of course would be both impossible and unproductive. The test for whether a theory is sufficiently non-partial is whether it is fit for purpose and whether it contributes to human flourishing.

...

Analytic philosophers pride themselves on trying to do away with vagueness. To do so, they tend to jettison context which cannot be brought into fine focus. However, in order to understand things and discern their meaning, it is necessary to have the big picture, the overview, as well as the details. There is no point in having details if the subject does not know what they are details of. Such philosophers also tend to leave themselves out of the picture even when what they are thinking about has reflexive implications. John Locke, for instance, tried to banish the RH from reality. All phenomena having to do with subjective experience he deemed unreal and once remarked about metaphors, a RH phenomenon, that they are “perfect cheats.” Analytic philosophers tend to check the logic of the words on the page and not to think about what those words might say about them. The trick is for them to recognize that they and their theories, which exist in minds, are part of reality too.

The RH test for whether someone actually believes something can be found by examining his actions. If he finds that he must regard his own actions as free, and, in order to get along with other people, must also attribute free will to them and treat them as free agents, then he effectively believes in free will – no matter his LH theoretical commitments.

...

We do not know the origin of life. We do not know how or even if consciousness can emerge from matter. We do not know the nature of 96% of the matter of the universe. Clearly all these things exist. They can provide the subject matter of theories but they continue to exist as theorizing ceases or theories change. Not knowing how something is possible is irrelevant to its actual existence. An inability to explain something is ultimately neither here nor there.

If thought begins and ends with the LH, then thinking has no content – content being provided by experience (RH), and skepticism and nihilism ensue. The LH spins its wheels self-referentially, never referring back to experience. Theory assumes such primacy that it will simply outlaw experiences and data inconsistent with it; a profoundly wrong-headed approach.

...

Gödel’s Theorem proves that not everything true can be proven to be true. This means there is an ineradicable role for faith, hope and intuition in every moderately complex human intellectual endeavor. There is no one set of consistent axioms from which all other truths can be derived.

Alan Turing’s proof of the halting problem proves that there is no effective procedure for finding effective procedures. Without a mechanical decision procedure, (LH), when it comes to … [more]
gnon  reflection  books  summary  review  neuro  neuro-nitgrit  things  thinking  metabuch  order-disorder  apollonian-dionysian  bio  examples  near-far  symmetry  homo-hetero  logic  inference  intuition  problem-solving  analytical-holistic  n-factor  europe  the-great-west-whale  occident  alien-character  detail-architecture  art  theory-practice  philosophy  being-becoming  essence-existence  language  psychology  cog-psych  egalitarianism-hierarchy  direction  reason  learning  novelty  science  anglo  anglosphere  coarse-fine  neurons  truth  contradiction  matching  empirical  volo-avolo  curiosity  uncertainty  theos  axioms  intricacy  computation  analogy  essay  rhetoric  deep-materialism  new-religion  knowledge  expert-experience  confidence  biases  optimism  pessimism  realness  whole-partial-many  theory-of-mind  values  competition  reduction  subjective-objective  communication  telos-atelos  ends-means  turing  fiction  increase-decrease  innovation  creative  thick-thin  spengler  multi  ratty  hanson  complex-systems  structure  concrete  abstraction  network-s 
september 2018 by nhaliday
Effects of Education on Political Opinions: An International Study | International Journal of Public Opinion Research | Oxford Academic
Education and Political Party: The Effects of College or Social Class?: https://www.jstor.org/stable/2778029
The impact of education on political ideology: Evidence from European compulsory education reforms: https://www.sciencedirect.com/science/article/pii/S0272775716301704
correlation is with leftism, causal effect is shift to right

Greg thinks there are some effects: https://pinboard.in/u:nhaliday/b:5adca8f16265

https://twitter.com/GarettJones/status/964209775419457536
https://archive.is/oFELz
https://archive.is/f1DBF
https://archive.is/5iiqn

http://econlog.econlib.org/archives/2008/12/education_ideol.html

https://twitter.com/pseudoerasmus/status/963451867912130561
https://archive.is/sHI7g
https://archive.is/B5Gdv
https://archive.is/hFERC
https://archive.is/8IUDm
Bryan Caplan has written a very persuasive book suggesting that retention/transfer of learning is very low. how do we know it’s not the same with the “PoMo ethos”
study  polisci  sociology  education  higher-ed  intervention  branches  politics  ideology  world  general-survey  correlation  causation  left-wing  right-wing  phalanges  multi  coalitions  history  mostly-modern  usa  cold-war  europe  EU  natural-experiment  endogenous-exogenous  direction  west-hunter  scitariat  twitter  social  discussion  backup  econotariat  garett-jones  cracker-econ  data  analysis  regression  org:econlib  biodet  behavioral-gen  variance-components  environmental-effects  counter-revolution  strategy  tactics  pseudoE  demographics  race  gender  markets  impetus  roots  explanans  migration  social-norms 
february 2018 by nhaliday
Is the speed of light really constant?
So what if the speed of light isn’t the same when moving toward or away from us? Are there any observable consequences? Not to the limits of observation so far. We know, for example, that any one-way speed of light is independent of the motion of the light source to 2 parts in a billion. We know it has no effect on the color of the light emitted to a few parts in 1020. Aspects such as polarization and interference are also indistinguishable from standard relativity. But that’s not surprising, because you don’t need to assume isotropy for relativity to work. In the 1970s, John Winnie and others showed that all the results of relativity could be modeled with anisotropic light so long as the two-way speed was a constant. The “extra” assumption that the speed of light is a uniform constant doesn’t change the physics, but it does make the mathematics much simpler. Since Einstein’s relativity is the simpler of two equivalent models, it’s the model we use. You could argue that it’s the right one citing Occam’s razor, or you could take Newton’s position that anything untestable isn’t worth arguing over.

SPECIAL RELATIVITY WITHOUT ONE-WAY VELOCITY ASSUMPTIONS:
https://sci-hub.bz/https://www.jstor.org/stable/186029
https://sci-hub.bz/https://www.jstor.org/stable/186671
nibble  scitariat  org:bleg  physics  relativity  electromag  speed  invariance  absolute-relative  curiosity  philosophy  direction  gedanken  axioms  definition  models  experiment  space  science  measurement  volo-avolo  synchrony  uniqueness  multi  pdf  piracy  study  article 
november 2017 by nhaliday
Hyperbolic angle - Wikipedia
A unit circle {\displaystyle x^{2}+y^{2}=1} x^2 + y^2 = 1 has a circular sector with an area half of the circular angle in radians. Analogously, a unit hyperbola {\displaystyle x^{2}-y^{2}=1} {\displaystyle x^{2}-y^{2}=1} has a hyperbolic sector with an area half of the hyperbolic angle.
nibble  math  trivia  wiki  reference  physics  relativity  concept  atoms  geometry  ground-up  characterization  measure  definition  plots  calculation  nitty-gritty  direction  metrics  manifolds 
november 2017 by nhaliday
general relativity - What if the universe is rotating as a whole? - Physics Stack Exchange
To find out whether the universe is rotating, in principle the most straightforward test is to watch the motion of a gyroscope relative to the distant galaxies. If it rotates at an angular velocity -ω relative to them, then the universe is rotating at angular velocity ω. In practice, we do not have mechanical gyroscopes with small enough random and systematic errors to put a very low limit on ω. However, we can use the entire solar system as a kind of gyroscope. Solar-system observations put a model-independent upper limit of 10^-7 radians/year on the rotation,[Clemence 1957] which is an order of magnitude too lax to rule out the Gödel metric.
nibble  q-n-a  overflow  physics  relativity  gedanken  direction  absolute-relative  big-picture  space  experiment  measurement  volo-avolo 
november 2017 by nhaliday
Section 10 Chi-squared goodness-of-fit test.
- pf that chi-squared statistic for Pearson's test (multinomial goodness-of-fit) actually has chi-squared distribution asymptotically
- the gotcha: terms Z_j in sum aren't independent
- solution:
- compute the covariance matrix of the terms to be E[Z_iZ_j] = -sqrt(p_ip_j)
- note that an equivalent way of sampling the Z_j is to take a random standard Gaussian and project onto the plane orthogonal to (sqrt(p_1), sqrt(p_2), ..., sqrt(p_r))
- that is equivalent to just sampling a Gaussian w/ 1 less dimension (hence df=r-1)
QED
pdf  nibble  lecture-notes  mit  stats  hypothesis-testing  acm  probability  methodology  proofs  iidness  distribution  limits  identity  direction  lifts-projections 
october 2017 by nhaliday
Biopolitics | West Hunter
I have said before that no currently popular ideology acknowledges well-established results of behavioral genetics, quantitative genetics, or psychometrics. Or evolutionary psychology.

What if some ideology or political tradition did? what could they do? What problems could they solve, what capabilities would they have?

Various past societies knew a few things along these lines. They knew that there were significant physical and behavioral differences between the sexes, which is forbidden knowledge in modern academia. Some knew that close inbreeding had negative consequences, which knowledge is on its way to the forbidden zone as I speak. Some cultures with wide enough geographical experience had realistic notions of average cognitive differences between populations. Some people had a rough idea about regression to the mean [ in dynasties], and the Ottomans came up with a highly unpleasant solution – the law of fratricide. The Romans, during the Principate, dealt with the same problem through imperial adoption. The Chinese exam system is in part aimed at the same problem.

...

At least some past societies avoided the social patterns leading to the nasty dysgenic trends we are experiencing today, but for the most part that is due to the anthropic principle: if they’d done something else you wouldn’t be reading this. Also to between-group competition: if you fuck your self up when others don’t, you may be well be replaced. Which is still the case.

If you were designing an ideology from scratch you could make use of all of these facts – not that thinking about genetics and selection hands you the solution to every problem, but you’d have more strings to your bow. And, off the top of your head, you’d understand certain trends that are behind the mountains of Estcarp, for our current ruling classes : invisible and unthinkable, That Which Must Not Be Named. .

https://westhunt.wordpress.com/2017/10/08/biopolitics/#comment-96613
“The closest…s the sort of libertarianism promulgated by Charles Murray”
Not very close..
A government that was fully aware of the implications and possibilities of human genetics, one that had the usual kind of state goals [ like persistence and increased power] , would not necessarily be particularly libertarian.

https://westhunt.wordpress.com/2017/10/08/biopolitics/#comment-96797
And giving tax breaks to college-educated liberals to have babies wouldn’t appeal much to Trump voters, methinks.

It might be worth making a reasonably comprehensive of the facts and preferences that a good liberal is supposed to embrace and seem to believe. You would have to be fairly quick about it, before it changes. Then you could evaluate about the social impact of having more of them.

Rise and Fall: https://westhunt.wordpress.com/2018/01/18/rise-and-fall/
Every society selects for something: generally it looks as if the direction of selection pressue is more or less an accident. Although nations and empires in the past could have decided to select men for bravery or intelligence, there’s not much sign that anyone actually did this. I mean, they would have known how, if they’d wanted to, just as they knew how to select for destriers, coursers, and palfreys. It was still possible to know such things in the Middle Ages, because Harvard did not yet exist.

A rising empire needs quality human capital, which implies that at minimum that budding imperial society must not have been strongly dysgenic. At least not in the beginning. But winning changes many things, possibly including selective pressures. Imagine an empire with substantial urbanization, one in which talented guys routinely end up living in cities – cities that were demographic sinks. That might change things. Or try to imagine an empire in which survival challenges are greatly reduced, at least for elites, so that people have nothing to keep their minds off their minds and up worshiping Magna Mater. Imagine that an empire that conquers a rival with interesting local pathogens and brings some of them home. Or one that uses up a lot of its manpower conquering less-talented subjects and importing masses of those losers into the imperial heartland.

If any of those scenarios happened valid, they might eventually result in imperial decline – decline due to decreased biological capital.

Right now this is speculation. If we knew enough about the GWAS hits for intelligence, and had enough ancient DNA, we might be able to observe that rise and fall, just as we see dysgenic trends in contemporary populations. But that won’t happen for a long time. Say, a year.

hmm: https://westhunt.wordpress.com/2018/01/18/rise-and-fall/#comment-100350
“Although nations and empires in the past could have decided to select men for bravery or intelligence, there’s not much sign that anyone actually did this.”

Maybe the Chinese imperial examination could effectively have been a selection for intelligence.
--
Nope. I’ve modelled it: the fraction of winners is far too small to have much effect, while there were likely fitness costs from the arduous preparation. Moreover, there’s a recent
paper [Detecting polygenic adaptation in admixture graphs] that looks for indications of when selection for IQ hit northeast Asia: quite a while ago. Obvious though, since Japan has similar scores without ever having had that kind of examination system.

decline of British Empire and utility of different components: https://westhunt.wordpress.com/2018/01/18/rise-and-fall/#comment-100390
Once upon a time, India was a money maker for the British, mainly because they appropriate Bengali tax revenue, rather than trade. The rest of the Empire was not worth much: it didn’t materially boost British per-capita income or military potential. Silesia was worth more to Germany, conferred more war-making power, than Africa was to Britain.
--
If you get even a little local opposition, a colony won’t pay for itself. I seem to remember that there was some, in Palestine.
--
Angels from on high paid for the Boer War.

You know, someone in the 50’s asked for the numbers – how much various colonies cost and how much they paid.

Turned out that no one had ever asked. The Colonial Office had no idea.
west-hunter  scitariat  discussion  ideas  politics  polisci  sociology  anthropology  cultural-dynamics  social-structure  social-science  evopsych  agri-mindset  pop-diff  kinship  regression-to-mean  anthropic  selection  group-selection  impact  gender  gender-diff  conquest-empire  MENA  history  iron-age  mediterranean  the-classics  china  asia  sinosphere  technocracy  scifi-fantasy  aphorism  alt-inst  recruiting  applications  medieval  early-modern  institutions  broad-econ  biodet  behavioral-gen  gnon  civilization  tradition  leviathan  elite  competition  cocktail  🌞  insight  sapiens  arbitrage  paying-rent  realness  kumbaya-kult  war  slippery-slope  unintended-consequences  deep-materialism  inequality  malthus  dysgenics  multi  murray  poast  speculation  randy-ayndy  authoritarianism  time-preference  patience  long-short-run  leadership  coalitions  ideology  rant  westminster  truth  flux-stasis  new-religion  identity-politics  left-wing  counter-revolution  fertility  signaling  status  darwinian  orwellian  ability-competence  organizing 
october 2017 by nhaliday
Centers of gravity in non-uniform fields - Wikipedia
In physics, a center of gravity of a material body is a point that may be used for a summary description of gravitational interactions. In a uniform gravitational field, the center of mass serves as the center of gravity. This is a very good approximation for smaller bodies near the surface of Earth, so there is no practical need to distinguish "center of gravity" from "center of mass" in most applications, such as engineering and medicine.

In a non-uniform field, gravitational effects such as potential energy, force, and torque can no longer be calculated using the center of mass alone. In particular, a non-uniform gravitational field can produce a torque on an object, even about an axis through the center of mass. The center of gravity seeks to explain this effect. Formally, a center of gravity is an application point of the resultant gravitational force on the body. Such a point may not exist, and if it exists, it is not unique. One can further define a unique center of gravity by approximating the field as either parallel or spherically symmetric.

The concept of a center of gravity as distinct from the center of mass is rarely used in applications, even in celestial mechanics, where non-uniform fields are important. Since the center of gravity depends on the external field, its motion is harder to determine than the motion of the center of mass. The common method to deal with gravitational torques is a field theory.
nibble  wiki  reference  physics  mechanics  intricacy  atoms  expectancy  spatial  direction  ground-up  concept  existence  uniqueness  homo-hetero  gravity  gotchas 
september 2017 by nhaliday
Why is Earth's gravity stronger at the poles? - Physics Stack Exchange
The point is that if we approximate Earth with an oblate ellipsoid, then the surface of Earth is an equipotential surface,11 see e.g. this Phys.SE post.

Now, because the polar radius is smaller than the equatorial radius, the density of equipotential surfaces at the poles must be bigger than at the equator.

Or equivalently, the field strength22 gg at the poles must be bigger than at the equator.
nibble  q-n-a  overflow  physics  mechanics  gravity  earth  space  intricacy  explanation  tidbits  spatial  direction  nitty-gritty  geography 
september 2017 by nhaliday
Does your weight change between the poles and the equator? (Intermediate) - Curious About Astronomy? Ask an Astronomer
You are right, that because of centrifugal force you will weigh a tiny amount less at the Equator than at the poles. Try not to think of centrifugal force as a force though; what's really going on is that objects which are in motion like to go in a straight line and so it takes some force to make them go round in a circle. (Centrifugal force is a fictitious force that shows up in the equations of motion for an object in a rotating reference frame - such as on Earth's Equator.)

So some of the force of gravity (centripetal force) is being used to make you go around in a circle at the Equator (instead of flying off into space) while at the pole this is not needed. The centripetal acceleration at the Equator is given by four times pi squared times the radius of the Earth divided by the period of rotation squared (4×π2×R/T2). Earth's period of rotation is a sidereal day (86164.1 seconds, slightly less than 24 hours), and the equatorial radius of the Earth is about 6378 km. This means that the centripetal acceleration at the Equator is about 0.03 m/s2 (metres per second squared). Compare this to the acceleration due to gravity which is about 9.8 m/s2 and you can see how tiny an effect this is - you would weigh about 0.3% less at the equator than at the poles!

There is an additional effect due to the oblateness of the Earth. The Earth is not exactly spherical but rather is a little bit like a "squashed" sphere (technically, an oblate spheroid), with the radius at the Equator slightly larger than the radius at the poles. (This shape can be explained by the effect of centrifugal acceleration on the material that makes up the Earth, exactly as described above.) This has the effect of slightly increasing your weight at the poles (since you are close to the centre of the Earth and the gravitational force depends on distance) and slightly decreasing it at the equator.

Taking into account both of the above effects, the gravitational acceleration is 9.78 m/s2 at the equator and 9.83 m/s2 at the poles, so you weigh about 0.5% more at the poles than at the equator.
nibble  q-n-a  org:edu  popsci  physics  mechanics  gravity  direction  absolute-relative  homo-hetero  earth  space  data  spatial  org:junk  marginal  explanation  geography 
september 2017 by nhaliday
Gimbal lock - Wikipedia
Gimbal lock is the loss of one degree of freedom in a three-dimensional, three-gimbal mechanism that occurs when the axes of two of the three gimbals are driven into a parallel configuration, "locking" the system into rotation in a degenerate two-dimensional space.

The word lock is misleading: no gimbal is restrained. All three gimbals can still rotate freely about their respective axes of suspension. Nevertheless, because of the parallel orientation of two of the gimbals' axes there is no gimbal available to accommodate rotation along one axis.

https://blender.stackexchange.com/questions/469/could-someone-please-explain-gimbal-lock
https://computergraphics.stackexchange.com/questions/4436/how-to-achieve-gimbal-lock-with-euler-angles
Now this is where most people stop thinking about the issue and move on with their life. They just conclude that Euler angles are somehow broken. This is also where a lot of misunderstandings happen so it's worth investigating the matter slightly further than what causes gimbal lock.

It is important to understand that this is only problematic if you interpolate in Euler angles**! In a real physical gimbal this is given - you have no other choice. In computer graphics you have many other choices, from normalized matrix, axis angle or quaternion interpolation. Gimbal lock has a much more dramatic implication to designing control systems than it has to 3d graphics. Which is why a mechanical engineer for example will have a very different take on gimbal locking.

You don't have to give up using Euler angles to get rid of gimbal locking, just stop interpolating values in Euler angles. Of course, this means that you can now no longer drive a rotation by doing direct manipulation of one of the channels. But as long as you key the 3 angles simultaneously you have no problems and you can internally convert your interpolation target to something that has less problems.

Using Euler angles is just simply more intuitive to think in most cases. And indeed Euler never claimed it was good for interpolating but just that it can model all possible space orientations. So Euler angles are just fine for setting orientations like they were meant to do. Also incidentally Euler angles have the benefit of being able to model multi turn rotations which will not happen sanely for the other representations.
nibble  dirty-hands  physics  mechanics  robotics  degrees-of-freedom  measurement  gotchas  volo-avolo  duplication  wiki  reference  multi  q-n-a  stackex  graphics  spatial  direction  dimensionality  sky 
september 2017 by nhaliday
rotational dynamics - Why do non-rigid bodies try to increase their moment of inertia? - Physics Stack Exchange
This happens to isolated rotating system that is not a rigid body.

Inside such a body (for example, steel chain in free fall) the parts move relatively to each other and there is internal friction that dissipates kinetic energy of the system, while angular momentum is conserved. The dissipation goes on until the parts stop moving with respect to each other, so body rotates as a rigid body, even if it is not rigid by constitution.

The rotating state of the body that has the lowest kinetic energy for given angular momentum is that in which the body has the greatest moment of inertia (with respect to center of mass). For example, a long chain thrown into free fall will twist and turn until it is all straight and rotating as rigid body.

...

If LL is constant (net torque of external forces acting on the system is zero) and the constitution and initial conditions allow it, the system's dissipation will work to diminish energy until it has the minimum value, which happens for maximum IaIa possible.
nibble  q-n-a  overflow  physics  mechanics  tidbits  spatial  rigidity  flexibility  invariance  direction  stylized-facts  dynamical  volo-avolo  street-fighting  yoga 
august 2017 by nhaliday
Tidal locking - Wikipedia
The Moon's rotation and orbital periods are tidally locked with each other, so no matter when the Moon is observed from Earth the same hemisphere of the Moon is always seen. The far side of the Moon was not seen until 1959, when photographs of most of the far side were transmitted from the Soviet spacecraft Luna 3.[12]

never actually thought about this
nibble  wiki  reference  space  mechanics  gravity  navigation  explanation  flux-stasis  marginal  volo-avolo  spatial  direction  invariance  physics  flexibility  rigidity  time  identity  phase-transition  being-becoming 
august 2017 by nhaliday
Dadly adaptations | West Hunter
If we understood how this works, we might find that individuals and populations vary in their propensity to show paternal care ( for genetic reasons). I would guess that paternal care was ancestral in modern humans, but it’s easy enough to lose something like this when selective pressures no longer favor it. Wolves have paternal care, but dogs have lost it.

This could have something to do with better health in married men. High testosterone levels aren’t cost-free.

It’s possible that various modern environmental factors interfere with the triggers for dadliness. That would hardly be surprising, since we don’t really know how they work.

All this has a number of interesting social implications. Let’s see how many of them you guys can spot.

Poles in the Tent: https://westhunt.wordpress.com/2013/07/09/poles-in-the-tent/
I’m considering a different question: what was the impact of men’s contribution on their children’s survival and fitness? That’s not quite the same as the number of calories contributed. Food is not a single undifferentiated quantity: it’s a category, including a number of different kinds that can’t be freely substituted for each other. Proteins, fats, and carbohydrates can all serve as fuel, but you need protein to build tissue. And amino acids, the building blocks of proteins, are not all fungible. Some we can’t synthesize (essential amino acids) others can only be synthesized from a limited set of precursors, etc. Edible plants often have suboptimal mixes of amino acids ( too many Qs, not enough Us) , but I’ve never heard of this being a problem with meat. Then you have to consider essential fatty acids, vitamins, and trace elements.

In principle, if high-quality protein were the long pole in the tent, male provisioning of meat, which we see in chimpanzees, might matter quite a bit more than you would think from the number of calories alone. I’m not say that is necessarily the case, but it might be, and it’s worth checking out.

Sexual selection vs job specialization: https://westhunt.wordpress.com/2017/10/02/sexual-selection-vs-job-specialization/
Pretty much every species is subject to sexual selection: heritable characteristics that lead to more mates or better mates can be favored by natural selection. Typically, sexual selection favors different strategies in males and females. Generally, males can gain fitness with increased mating opportunities, while females gain more from high-quality mates or mates that confer resources. Since the variance in reproduction is usually greater in males than females, sexual selection is usually stronger in males, although it exists and is significant in both sexes.

Usually, though, males and females of a given species have very similar ways of making a living. A male deer and a female deer both eat grass or arugula or whatever. Sexual selection may drive them to evolve in different directions, but finding something to eat mostly drives them in the same direction.

Humans are an exception. In the long past, men hunted and women gathered. The mix varied: in Arctic regions, men produce almost all the food (while women made and repaired gear, as well as raising children). In groups like the Bushmen, women produced most of the calories, but done rightly you would count more than calories: if most of the local plants had low protein or low-quality protein (wrong amino acid mix), meat from hunting could be important out of proportion to its caloric value.

This has been going for a long time, so there must have been selection for traits that aided provisioning ability in each sex. Those job-related selective pressures probably changed with time. For example, male strength may have become less valuable when the Bushmen developed poison arrows.

I was looking for an intelligent discussion of this question – but I ran into this and couldn’t force myself to read further: ” It should not simply be assumed that the exclusion of women from hunting rests upon “natural” physiological differences. ”

God give me strength.

https://westhunt.wordpress.com/2017/10/02/sexual-selection-vs-job-specialization/#comment-96323
What does Greg think about the “plows vs hoes” theory? (As seen here, although Sarah Constantin didn’t invent it.)

The claim is that some societies adopted farming (Europe, the Middle East, Asia) while some societies adopted horticulture (Oceana, sub-Saharan Africa, various primitive peoples) and that this had an affect on gender relations.

Basically: farming is backbreaking work, which favours males, giving them a lot of social capital. You end up with a patriarchal kind of society, where the men do stuff and the women are mostly valuable for raising offspring.

...

It’s kinda true, in places. There is a connection I haven’t seen explicated: the ‘hoe culture” has to have some factor keeping population density low, so that labor is scarcer than land. Tropical diseases like malaria might be part of that. Then again, crops like yams don’t store well, better to keep them in the ground until eating. That means it’s hard to tax people – easy with grain bins. No taxes -> no State – > high local violence. At times, VD may also help limit density, cf Africa’s ‘sterility belt’.

I am not a Moron: https://westhunt.wordpress.com/2017/11/03/i-am-not-a-moron/
So said Augustin Fuentes on Twitter, a few days ago. He’s the same guy that said “Genes don’t do anything by themselves; epigenetics and complex metabolic and developmental systems are at play in how bodies work. The roundworm C. elegans has about 20,000 genes while humans have about 23,000 genes, yet it is pretty obvious that humans are more than 15-percent more complex than roundworms. So while genes matter, they are only a small part of the whole evolutionary picture. Focusing just on DNA won’t get you anywhere.”

Fuentes was claiming that we don’t really know that, back in prehistory, men did most of the hunting while women gathered.

...

Someone (Will@Evolving _Moloch) criticized this as a good candidate for the most misleading paragraph ever written. The folly of youth! When you’ve been around as long as I have, sonny, you will realize how hard it is to set records for stupidity.

Fuente’s para is multidimensional crap, of course. People used to hunt animals like red deer, or bison, or eland: sometimes mammoths or rhinos. Big animals. Back in the day, our ancestors used stabbing spears, which go back at least half a million years. Stand-off weapons like atlatls, or bows, or JSOW, are relatively recent. Hunters took big risks & suffered frequent injuries. Men are almost twice as strong as women, particularly in upper-body strength, which is what matters in spear-chucking. They’re also faster, which can be very important which your ambush fails.
So men did the hunting. This isn’t complicated.

Which contemporary hunter-gather societies followed this pattern, had men do almost all of the big-game hunting? All of them.

...

Look, feminists aren’t happy with human nature, the one that actually exists and is the product of long-term evolutionary pressures. Too bad for them. When they say stuff like “It should not simply be assumed that the exclusion of women from hunting rests upon “natural” physiological differences. “, they just sound like fools.. ‘natural physiological differences” exist. They’re as obvious a punch in the kisser.

Suppose you wanted to construct a society with effective sexual equality – which is probably just a mistake, but suppose it. The most effective approach would surely entail knowing and taking into account how the world actually ticks. You’d be better off understanding that about 6,000 genes (out of 20,000) show significant expression differences between the sexes, than by pretending that we’re all the same. You would to make it so: by hook or by crook, by state force and genetic engineering.

Similarly, if you want to minimize war, pretending that people aren’t warlike is a poor start – about as sensible as fighting forest fires by pretending that trees aren’t flammable.

My advice to Augustin Fuentes, about not being a moron: show, don’t tell.

https://westhunt.wordpress.com/2017/11/03/i-am-not-a-moron/#comment-97721
Since DNA is the enduring part, the part that gets transmitted from one generation to the next, the part that contains the instructions/program that determine development and specify everything – he’s wrong. Stupid, like you. Well, to be fair, ignorant as well: there are technical aspects of genetics that Agustin Fuentes is unlikely to know anything about, things that are almost never covered in the typical education of an anthropologist. I doubt if he knows what a Fisher wave is, or anything about selfish genetic elements, or coalescent theory, or for that matter the breeder’s equation.

There are a number of complex technical subjects, things that at least some people understand: those people can do stuff that the man in the street can’t. In most cases, amateurs don’t jump in and pretend to know what’s going on. For example you don’t hear much concerning amateur opinions concerning detonation physics or group theory. But they’re happy to have opinions about natural selection, even though they know fuck-all about it.

https://twitter.com/FinchesofDarwin/status/922924692389818368
https://archive.is/AcBgh
"Significantly fewer females are present at hunts than males...females tend to appear at the hunting site once the capture has been made..."

“Women in Tech”: https://bloodyshovel.wordpress.com/2017/10/26/women-in-tech/
west-hunter  scitariat  discussion  ideas  pop-diff  biodet  behavioral-gen  endocrine  parenting  life-history  speculation  time-preference  temperance  health  counter-revolution  rot  zeitgeist  environmental-effects  science-anxiety  legacy  incentives  sapiens  multi  farmers-and-foragers  food  gender  gender-diff  intricacy  dimensionality  agriculture  selection  symmetry  comparison  leviathan  cultural-dynamics  peace-violence  taxes  broad-econ  microfoundations  africa  europe  asia  MENA  world  developing-world  🌞  order-disorder  population  density  scale  stylized-facts  cocktail  anthropology  roots  parasites-microbiome  phalanges  things  analogy  direction  rant  EEA  evopsych  is-ought  attaq  data  genetics  genomics  war  people  track-record  poast  population-genetics  selfish-gene  magnitude  twitter  social  commentary  backup  quotes  gnon  right-wing  aphorism  sv  tech  identity-politics  envy  allodium  outcome-risk  hari-seldon 
june 2017 by nhaliday
[1705.03394] That is not dead which can eternal lie: the aestivation hypothesis for resolving Fermi's paradox
If a civilization wants to maximize computation it appears rational to aestivate until the far future in order to exploit the low temperature environment: this can produce a 10^30 multiplier of achievable computation. We hence suggest the "aestivation hypothesis": the reason we are not observing manifestations of alien civilizations is that they are currently (mostly) inactive, patiently waiting for future cosmic eras. This paper analyzes the assumptions going into the hypothesis and how physical law and observational evidence constrain the motivations of aliens compatible with the hypothesis.

http://aleph.se/andart2/space/the-aestivation-hypothesis-popular-outline-and-faq/

simpler explanation (just different math for Drake equation):
Dissolving the Fermi Paradox: http://www.jodrellbank.manchester.ac.uk/media/eps/jodrell-bank-centre-for-astrophysics/news-and-events/2017/uksrn-slides/Anders-Sandberg---Dissolving-Fermi-Paradox-UKSRN.pdf
http://marginalrevolution.com/marginalrevolution/2017/07/fermi-paradox-resolved.html
Overall the argument is that point estimates should not be shoved into a Drake equation and then multiplied by each, as that requires excess certainty and masks much of the ambiguity of our knowledge about the distributions. Instead, a Bayesian approach should be used, after which the fate of humanity looks much better. Here is one part of the presentation:

Life Versus Dark Energy: How An Advanced Civilization Could Resist the Accelerating Expansion of the Universe: https://arxiv.org/abs/1806.05203
The presence of dark energy in our universe is causing space to expand at an accelerating rate. As a result, over the next approximately 100 billion years, all stars residing beyond the Local Group will fall beyond the cosmic horizon and become not only unobservable, but entirely inaccessible, thus limiting how much energy could one day be extracted from them. Here, we consider the likely response of a highly advanced civilization to this situation. In particular, we argue that in order to maximize its access to useable energy, a sufficiently advanced civilization would chose to expand rapidly outward, build Dyson Spheres or similar structures around encountered stars, and use the energy that is harnessed to accelerate those stars away from the approaching horizon and toward the center of the civilization. We find that such efforts will be most effective for stars with masses in the range of M∼(0.2−1)M⊙, and could lead to the harvesting of stars within a region extending out to several tens of Mpc in radius, potentially increasing the total amount of energy that is available to a future civilization by a factor of several thousand. We also discuss the observable signatures of a civilization elsewhere in the universe that is currently in this state of stellar harvesting.
preprint  study  essay  article  bostrom  ratty  anthropic  philosophy  space  xenobio  computation  physics  interdisciplinary  ideas  hmm  cocktail  temperature  thermo  information-theory  bits  🔬  threat-modeling  time  scale  insight  multi  commentary  liner-notes  pdf  slides  error  probability  ML-MAP-E  composition-decomposition  econotariat  marginal-rev  fermi  risk  org:mat  questions  paradox  intricacy  multiplicative  calculation  street-fighting  methodology  distribution  expectancy  moments  bayesian  priors-posteriors  nibble  measurement  existence  technology  geoengineering  magnitude  spatial  density  spreading  civilization  energy-resources  phys-energy  measure  direction  speculation  structure 
may 2017 by nhaliday
Deming regression - Wikipedia
Deming regression. The red lines show the error in both x and y. This is different from the traditional least squares method which measures error parallel to the y axis. The case shown, with deviations measured perpendicularly, arises when errors in x and y have equal variances.

https://en.wikipedia.org/wiki/Errors-in-variables_models
stats  data-science  regression  methodology  direction  noise-structure  wiki  reference  nibble  multi 
may 2017 by nhaliday
Typos | West Hunter
In a simple model, a given mutant has an equilibrium frequency μ/s, when μ is the mutation rate from good to bad alleles and s is the size of the selective disadvantage. To estimate the total impact of mutation at that locus, you multiply the frequency by the expected harm, s: which means that the fitness decrease (from effects at that locus) is just μ, the mutation rate. If we assume that these fitness effects are multiplicative, the total fitness decrease (also called ‘mutational load’) is approximately 1 – exp(-U), when U is where U=Σ2μ, the total number of new harmful mutations per diploid individual.

https://westhunt.wordpress.com/2012/10/17/more-to-go-wrong/

https://westhunt.wordpress.com/2012/07/13/sanctuary/
interesting, suggestive comment on Africa:
https://westhunt.wordpress.com/2012/07/13/sanctuary/#comment-3671
https://westhunt.wordpress.com/2012/07/14/too-darn-hot/
http://infoproc.blogspot.com/2012/07/rare-variants-and-human-genetic.html
https://westhunt.wordpress.com/2012/07/18/changes-in-attitudes/
https://westhunt.wordpress.com/2012/08/24/men-and-macaques/
I have reason to believe that few people understand genetic load very well, probably for self-referential reasons, but better explanations are possible.

One key point is that the amount of neutral variation is determined by the long-term mutational rate and population history, while the amount of deleterious variation [genetic load] is set by the selective pressures and the prevailing mutation rate over a much shorter time scale. For example, if you consider the class of mutations that reduce fitness by 1%, what matters is the past few thousand years, not the past few tens or hundreds of of thousands of years.

...

So, assuming that African populations have more neutral variation than non-African populations (which is well-established), what do we expect to see when we compare the levels of probably-damaging mutations in those two populations? If the Africans and non-Africans had experienced essentially similar mutation rates and selective pressures over the past few thousand years, we would expect to see the same levels of probably-damaging mutations. Bottlenecks that happened at the last glacial maximum or in the expansion out of Africa are irrelevant – too long ago to matter.

But we don’t. The amount of rare synonymous stuff is about 22% higher in Africans. The amount of rare nonsynonymous stuff (usually at least slightly deleterious) is 20.6% higher. The number of rare variants predicted to be more deleterious is ~21.6% higher. The amount of stuff predicted to be even more deleterious is ~27% higher. The number of harmful looking loss-of-function mutations (yet more deleterious) is 25% higher.

It looks as if the excess grows as the severity of the mutations increases. There is a scenario in which this is possible: the mutation rate in Africa has increased recently. Not yesterday, but, say, over the past few thousand years.

...

What is the most likely cause of such variations in the mutation rate? Right now, I’d say differences in average paternal age. We know that modest differences (~5 years) in average paternal age can easily generate ~20% differences in the mutation rate. Such between-population differences in mutation rates seem quite plausible, particularly since the Neolithic.
https://westhunt.wordpress.com/2016/04/10/bugs-versus-drift/
more recent: https://westhunt.wordpress.com/2017/06/06/happy-families-are-all-alike-every-unhappy-family-is-unhappy-in-its-own-way/#comment-92491
Probably not, but the question is complex: depends on the shape of the deleterious mutational spectrum [which we don’t know], ancient and recent demography, paternal age, and the extent of truncation selection in the population.
west-hunter  scitariat  discussion  bio  sapiens  biodet  evolution  mutation  genetics  genetic-load  population-genetics  nibble  stylized-facts  methodology  models  equilibrium  iq  neuro  neuro-nitgrit  epidemiology  selection  malthus  temperature  enhancement  CRISPR  genomics  behavioral-gen  multi  poast  africa  roots  pop-diff  ideas  gedanken  paternal-age  🌞  environment  speculation  gene-drift  longevity  immune  disease  parasites-microbiome  scifi-fantasy  europe  asia  race  migration  hsu  study  summary  commentary  shift  the-great-west-whale  nordic  intelligence  eden  long-short-run  debate  hmm  idk  explanans  comparison  structure  occident  mediterranean  geography  within-group  correlation  direction  volo-avolo  demographics  age-generation  measurement  data  applicability-prereqs  aging 
may 2017 by nhaliday
Reversal of the Gender Gap in Education, Motherhood, and Women as Main Earners in Europe | European Sociological Review | Oxford Academic
The Reversal of the Gender Gap in Education and
Female Breadwinners in Europe: http://www.familiesandsocieties.eu/wp-content/uploads/2015/01/WP26KlesmentVanBavel.pdf

A Record Share of Men Are “Marrying Up” Educationally: https://ifstudies.org/blog/a-record-share-of-men-are-marrying-up-educationally
Even though overall, wives have more education than their spouses today, men are still the primary provider in a majority of marriages. In 2015, more than 7-in-10 married men (73%) had a higher income than their spouse, although the share was down from 91% in 1960. During the same period, the share of married women who out-earned their spouses rose from 6% to 25%.

A Gender Reversal On Career Aspirations: http://www.pewsocialtrends.org/2012/04/19/a-gender-reversal-on-career-aspirations/
study  sociology  wonkish  demographics  europe  data  education  compensation  money  class  social-structure  gender  labor  trends  science-anxiety  life-history  dysgenics  social-norms  multi  pdf  rot  assortative-mating  news  org:ngo  time-series  dignity  poll  career  hmm  org:data  values  :/  current-events  direction  chart 
april 2017 by nhaliday
Lecture 11
In which we prove that the Edmonds-Karp algorithm for maximum flow is a strongly polynomial time algorithm, and we begin to talk about the push-relabel approach.
pdf  lecture-notes  exposition  optimization  algorithms  linear-programming  graphs  stanford  luca-trevisan  nibble  direction  stock-flow  tcs  constraint-satisfaction  tcstariat 
january 2017 by nhaliday
soft question - Thinking and Explaining - MathOverflow
- good question from Bill Thurston
- great answers by Terry Tao, fedja, Minhyong Kim, gowers, etc.

Terry Tao:
- symmetry as blurring/vibrating/wobbling, scale invariance
- anthropomorphization, adversarial perspective for estimates/inequalities/quantifiers, spending/economy

fedja walks through his though-process from another answer

Minhyong Kim: anthropology of mathematical philosophizing

Per Vognsen: normality as isotropy
comment: conjugate subgroup gHg^-1 ~ "H but somewhere else in G"

gowers: hidden things in basic mathematics/arithmetic
comment by Ryan Budney: x sin(x) via x -> (x, sin(x)), (x, y) -> xy
I kinda get what he's talking about but needed to use Mathematica to get the initial visualization down.
To remind myself later:
- xy can be easily visualized by juxtaposing the two parabolae x^2 and -x^2 diagonally
- x sin(x) can be visualized along that surface by moving your finger along the line (x, 0) but adding some oscillations in y direction according to sin(x)
q-n-a  soft-question  big-list  intuition  communication  teaching  math  thinking  writing  thurston  lens  overflow  synthesis  hi-order-bits  👳  insight  meta:math  clarity  nibble  giants  cartoons  gowers  mathtariat  better-explained  stories  the-trenches  problem-solving  homogeneity  symmetry  fedja  examples  philosophy  big-picture  vague  isotropy  reflection  spatial  ground-up  visual-understanding  polynomials  dimensionality  math.GR  worrydream  scholar  🎓  neurons  metabuch  yoga  retrofit  mental-math  metameta  wisdom  wordlessness  oscillation  operational  adversarial  quantifiers-sums  exposition  explanation  tricki  concrete  s:***  manifolds  invariance  dynamical  info-dynamics  cool  direction 
january 2017 by nhaliday
gt.geometric topology - Intuitive crutches for higher dimensional thinking - MathOverflow
Terry Tao:
I can't help you much with high-dimensional topology - it's not my field, and I've not picked up the various tricks topologists use to get a grip on the subject - but when dealing with the geometry of high-dimensional (or infinite-dimensional) vector spaces such as R^n, there are plenty of ways to conceptualise these spaces that do not require visualising more than three dimensions directly.

For instance, one can view a high-dimensional vector space as a state space for a system with many degrees of freedom. A megapixel image, for instance, is a point in a million-dimensional vector space; by varying the image, one can explore the space, and various subsets of this space correspond to various classes of images.

One can similarly interpret sound waves, a box of gases, an ecosystem, a voting population, a stream of digital data, trials of random variables, the results of a statistical survey, a probabilistic strategy in a two-player game, and many other concrete objects as states in a high-dimensional vector space, and various basic concepts such as convexity, distance, linearity, change of variables, orthogonality, or inner product can have very natural meanings in some of these models (though not in all).

It can take a bit of both theory and practice to merge one's intuition for these things with one's spatial intuition for vectors and vector spaces, but it can be done eventually (much as after one has enough exposure to measure theory, one can start merging one's intuition regarding cardinality, mass, length, volume, probability, cost, charge, and any number of other "real-life" measures).

For instance, the fact that most of the mass of a unit ball in high dimensions lurks near the boundary of the ball can be interpreted as a manifestation of the law of large numbers, using the interpretation of a high-dimensional vector space as the state space for a large number of trials of a random variable.

More generally, many facts about low-dimensional projections or slices of high-dimensional objects can be viewed from a probabilistic, statistical, or signal processing perspective.

Scott Aaronson:
Here are some of the crutches I've relied on. (Admittedly, my crutches are probably much more useful for theoretical computer science, combinatorics, and probability than they are for geometry, topology, or physics. On a related note, I personally have a much easier time thinking about R^n than about, say, R^4 or R^5!)

1. If you're trying to visualize some 4D phenomenon P, first think of a related 3D phenomenon P', and then imagine yourself as a 2D being who's trying to visualize P'. The advantage is that, unlike with the 4D vs. 3D case, you yourself can easily switch between the 3D and 2D perspectives, and can therefore get a sense of exactly what information is being lost when you drop a dimension. (You could call this the "Flatland trick," after the most famous literary work to rely on it.)
2. As someone else mentioned, discretize! Instead of thinking about R^n, think about the Boolean hypercube {0,1}^n, which is finite and usually easier to get intuition about. (When working on problems, I often find myself drawing {0,1}^4 on a sheet of paper by drawing two copies of {0,1}^3 and then connecting the corresponding vertices.)
3. Instead of thinking about a subset S⊆R^n, think about its characteristic function f:R^n→{0,1}. I don't know why that trivial perspective switch makes such a big difference, but it does ... maybe because it shifts your attention to the process of computing f, and makes you forget about the hopeless task of visualizing S!
4. One of the central facts about R^n is that, while it has "room" for only n orthogonal vectors, it has room for exp⁡(n) almost-orthogonal vectors. Internalize that one fact, and so many other properties of R^n (for example, that the n-sphere resembles a "ball with spikes sticking out," as someone mentioned before) will suddenly seem non-mysterious. In turn, one way to internalize the fact that R^n has so many almost-orthogonal vectors is to internalize Shannon's theorem that there exist good error-correcting codes.
5. To get a feel for some high-dimensional object, ask questions about the behavior of a process that takes place on that object. For example: if I drop a ball here, which local minimum will it settle into? How long does this random walk on {0,1}^n take to mix?

Gil Kalai:
This is a slightly different point, but Vitali Milman, who works in high-dimensional convexity, likes to draw high-dimensional convex bodies in a non-convex way. This is to convey the point that if you take the convex hull of a few points on the unit sphere of R^n, then for large n very little of the measure of the convex body is anywhere near the corners, so in a certain sense the body is a bit like a small sphere with long thin "spikes".
q-n-a  intuition  math  visual-understanding  list  discussion  thurston  tidbits  aaronson  tcs  geometry  problem-solving  yoga  👳  big-list  metabuch  tcstariat  gowers  mathtariat  acm  overflow  soft-question  levers  dimensionality  hi-order-bits  insight  synthesis  thinking  models  cartoons  coding-theory  information-theory  probability  concentration-of-measure  magnitude  linear-algebra  boolean-analysis  analogy  arrows  lifts-projections  measure  markov  sampling  shannon  conceptual-vocab  nibble  degrees-of-freedom  worrydream  neurons  retrofit  oscillation  paradox  novelty  tricki  concrete  high-dimension  s:***  manifolds  direction  curvature  convexity-curvature 
december 2016 by nhaliday
Psychological comments: Does Age make us sage or sag?
Khan on Twitter: "figure on right from @tuckerdrob lab is depressing (the knowledge plateau). do i read in vain??? https://t.co/DZzBD8onEv": https://twitter.com/razibkhan/status/809439911627493377
- reasoning rises then declines after age ~20
- knowledge plateaus by age 35-40
- different interpretation provided by study authors w/ another graph (renewal)
- study (can't find the exact graph anywhere): http://www.iapsych.com/wj3ewok/LinkedDocuments/McArdle2002.pdf

School’s out: https://westhunt.wordpress.com/2016/12/29/schools-out/
I saw a note by Razib Khan, in which he mentioned that psychometric research suggests that people plateau in their knowledge base as adults. I could believe it. But I’m not sure it’s true in my case. One might estimate total adult knowledge in terms of BS equivalents…

Age-related IQ decline is reduced markedly after adjustment for the Flynn effect: https://www.ncbi.nlm.nih.gov/m/pubmed/20349385/
Twenty-year-olds outperform 70-year-olds by as much as 2.3 standard deviations (35 IQ points) on subtests of the Wechsler Adult Intelligence Scale (WAIS). We show that most of the difference can be attributed to an intergenerational rise in IQ known as the Flynn effect.

...

For these verbal subtests, the Flynn effect masked a modest increase in ability as individuals grow older.

Predictors of ageing-related decline across multiple cognitive functions: http://www.sciencedirect.com/science/article/pii/S0160289616302707
Cognitive ageing is likely a process with few large-effect predictors

A strong link between speed of visual discrimination and cognitive ageing: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4123160/
Results showed a moderate correlation (r = 0.460) between inspection time performance and intelligence, and a strong correlation between change in inspection time and change in intelligence from 70 to 76 (r = 0.779). These results support the processing speed theory of cognitive ageing. They go beyond cross-sectional correlation to show that cognitive change is accompanied by changes in basic visual information processing as we age.
albion  psychology  cog-psych  psychometrics  aging  iq  objektbuch  long-term  longitudinal  study  summary  variance-components  scitariat  multi  gnxp  learning  metabuch  twitter  social  discussion  pic  data  planning  tradeoffs  flux-stasis  volo-avolo  west-hunter  studying  knowledge  age-generation  flexibility  rigidity  plots  manifolds  universalism-particularism  being-becoming  essence-existence  intelligence  stock-flow  large-factor  psych-architecture  visuo  correlation  time  speed  short-circuit  roots  flynn  trends  dysgenics  language  explanans  direction  chart 
december 2016 by nhaliday
Diamond on domestication | West Hunter
Jared Diamond, in discussing animal domestication, claims that the local availability of species with the right qualities for domestication was key, rather than anything special about the biology or culture of the humans living there. In some cases that may be true: there aren’t many large mammals left in Australia, and they’re all marsupials anyway. Stupid marsupials. He claims that since Africans and Amerindians were happy to adopt Eurasian domesticated animals when they became available, it must be that that suitable local animals just didn’t exist. But that’s a non sequitur: making use of an already-domesticated species is not at all the same thing as the original act of domestication. That’s like equating using a cell phone with inventing one. He also says that people have had only mixed success in recent domestication attempts – but the big problem there is that a newly domesticated species doesn’t just have to be good, it has to be better than already-existing domestic animals.

...

In fact, in my mind the real question is not why various peoples didn’t domesticate animals that we know were domesticable, but rather how anyone ever managed to domesticate the aurochs. At least twice. Imagine a longhorn on roids: they were big and aggressive, favorites in the Roman arena.

Let me throw out an idea originated by an old friend, Ivy Smith. Consider mice, cats, and toxoplasma. Toxoplasma is a protozoan with a two stage life cycle: one in an intermediate host (mice and rats, among others) and a definitive host (some feline). Toxoplasma only reproduces sexually in the definitive host, and it ‘wants’ to end up there. It manipulates the behavior of the intermediate host in ways that increase the probability of transmission to the definitive host. For one thing, it makes mice like the smell of cat urine, which elicits fear in uninfected mice. In fact, it seems that toxoplasma-infected mice are sexually excited by cat urine. How weird – a parasite rechanneling sexual interest…

The idea is that at least some individual aurochs were not as hostile and fearful of humans as they ought to have been, because they were being manipulated by some parasite. The parasite might have caused a general reduction of fear or aggression without infecting or aiming at humans – or, maybe, humans really were the definitive host, and the parasite knew exactly what it was doing. The beef tape worm – which we originally acquired from lions or hyenas back in Africa a couple of million years ago – might have gained from making infected bovines quiet, passive, maybe even overly friendly in the presence of humans. This would have made domestication a hell of a lot easier.

Parenthetically, such host manipulation may play a really important ecological role. For all we know, if canids and felids had to rely purely on their own abilities, they’d starve.

The beef tape worm may not have made it through Beringia. More generally, there were probably no parasites in the Americas that had some large mammal as intermediate host and Amerindians as the traditional definite host. Amerindians simply hadn’t been there very long. Domesticating bison may have too hard for unaided humans, back in the day.

https://westhunt.wordpress.com/2017/08/02/i-will-reread-and-review-jared-diamonds-book-guns-germs-and-steel/
https://westhunt.wordpress.com/category/ggs/
https://westhunt.wordpress.com/2017/08/03/why-the-aurochs-could-not-be-domesticated/
https://westhunt.wordpress.com/2017/08/04/buffalo-gourds-and-josephson-junctions/
Every technique is in competition with rival techniques. This inhibits the development of new techniques, even if they have high potential in the long run. To succeed, they have to beat out existing techniques in the short run.

For example, there are potential advantages for superconducting electronics for computing, but CMOS keeps improving. It’s a moving target: it’s not enough to be good, or interesting, you have to be better. Soon, not in 50 years. This is particularly difficult considering the enormous amount of resources currently invested in improving semiconductor computing technology.

In the same way, one successful domestication tends to inhibit other domestications. Several crops were domesticated in the eastern United States, but with the advent of maize and beans, most were abandoned. Maybe if those Amerindians had continued to selectively breed sumpweed for a few thousand years, it would have been competitive: but nobody is that crazy. Pretty crazy, but not that crazy.

https://westhunt.wordpress.com/2013/08/26/the-masters-of-the-future/
In Guns, Germs, and Steel, Jared Diamond argues that all human groups have equal mental capabilities – except for the inhabitants of New Guinea, who are clearly smarter than the human norm.

If this is the case, there’s money to be made. Good performance in a lot of high-paying jobs requires intelligence above some fairly high threshold. Such people are scarce [outside of New Guinea], and that means that their labor is expensive. The fraction of individuals above a high threshold increases dramatically with a higher mean, and since people in PNG don’t have high incomes, there is a fantastic arbitrage opportunity here. You could locate some of the many geniuses that must exist in PNG, rapidly and inexpensively teach them high-tech skills (which they would learn easily, since they’re geniuses, natch), apply for H1B visas, and them resell them to the highest Silicon Valley bidder. This wouldn’t last, of course – these guys would not stay peons forever. They’d be generating their own start-ups in a few years, founding hedge funds, dominating the Vegas poker tournaments, etc. Some, less materialistic, would become grandmasters, win Fields medals, or write seminal books about the attractions of cannibalism. Still, you could make a lot of money in the short run, and if you were careful to build good relationships with your employees, they might let you in on the ground floor of an IPO later.

Poul Anderson, always a visionary, foresaw this. A character in one his books put it thusly:” I am a racist – a dedicated, fanatical racist – who maintains, and can scientifically prove, that his own race is inferior. The only true humans on earth, my friends, the main line of evolution, the masters of the future, are the lordly Melanesians. ”

Of course that character was feigning insanity, but still.

https://westhunt.wordpress.com/2014/12/04/world-without-stars/#comment-63613
https://westhunt.wordpress.com/2017/08/08/png-data/
PNG = Papua New Guinea
https://westhunt.wordpress.com/2017/08/14/png-uber-alles/
https://westhunt.wordpress.com/2017/08/16/persistence/
https://westhunt.wordpress.com/2017/08/18/something-changed/
https://westhunt.wordpress.com/2017/08/21/psychometrics/
https://westhunt.wordpress.com/2017/08/22/regional-change/
https://westhunt.wordpress.com/2017/08/26/domesticated-animals-and-human-disease/
https://westhunt.wordpress.com/2017/08/29/not-without-honor/

final review:
Guns, Germs, and Steel revisited: https://westhunt.wordpress.com/2017/09/04/guns-germs-and-steel-revisited/

https://westhunt.wordpress.com/2017/09/04/guns-germs-and-steel-revisited/#comment-95596
He never says he was willing to wave the point, so how do you know that?

Next, europeans and Chinese ( northeast Asians) test smarter than anyone else. Noticeably so. And they act it, more or less. kinda sorta. More complicated mistakes.

https://westhunt.wordpress.com/2017/09/04/guns-germs-and-steel-revisited/#comment-95761
lower genetic diversity in Amerindians+possibility that fast mutating viruses might adapt to their host and hit relatives harder
west-hunter  technology  antiquity  sapiens  nature  speculation  parasites-microbiome  🌞  farmers-and-foragers  domestication  scitariat  ideas  questions  toxo-gondii  multi  books  review  critique  africa  agriculture  agri-mindset  long-short-run  incentives  info-dynamics  group-selection  gwern  india  asia  red-queen  pop-diff  poast  aphorism  developing-world  oceans  arbitrage  race  scifi-fantasy  psychometrics  psychology  cog-psych  iq  intelligence  psych-architecture  paying-rent  realness  disease  scale  civilization  population  density  prudence  marginal  novelty  earth  direction  geography  path-dependence  china  europe  immune  spreading  diversity  galor-like  genetics  genomics  alt-inst  competition  capitalism  cost-benefit  tradeoffs  big-peeps  sex  sexuality 
november 2016 by nhaliday
Divorce and children’s long-term outcomes | VOX, CEPR’s Policy Portal
It has been widely demonstrated that parental divorce is associated with negative outcomes for affected children. However, the degree of causality in this relationship is not as clear. This column tackles this problem by using the level of gender integration in fathers’ workplaces as an instrument for divorce. The results suggest a causal link between divorce and worse economic outcomes that persists into early adulthood.
http://ftp.iza.org/dp9928.pdf

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3904543/
The literature on father absence is frequently criticized for its use of cross-sectional data and methods that fail to take account of possible omitted variable bias and reverse causality. We review studies that have responded to this critique by employing a variety of innovative research designs to identify the causal effect of father absence, including studies using lagged dependent variable models, growth curve models, individual fixed effects models, sibling fixed effects models, natural experiments, and propensity score matching models. Our assessment is that studies using more rigorous designs continue to find negative effects of father absence on offspring well-being, although the magnitude of these effects is smaller than what is found using traditional cross-sectional designs. The evidence is strongest and most consistent for outcomes such as high school graduation, children’s social-emotional adjustment, and adult mental health.

Genetics, the Rearing Environment, and the Intergenerational Transmission of Divorce: A Swedish National Adoption Study: http://journals.sagepub.com/doi/abs/10.1177/0956797617734864
There was stronger resemblance to lived-with mothers, providing indirect evidence of rearing-environment influences on the intergenerational transmission of divorce. The heritability of divorce assessed across generations was 0.13. We attempted to replicate our findings using within-generation data from adoptive and biological siblings (ns = 8,523–53,097). Adoptees resembled their biological, not adoptive, siblings in their history of divorce. Thus, there was consistent evidence that genetic factors contributed to the intergenerational transmission of divorce but weaker evidence for a rearing-environment effect of divorce. Within-generation data from siblings supported these conclusions.

The Long-Term Effects of Legalizing Divorce on Children: http://onlinelibrary.wiley.com/doi/10.1111/obes.12200/abstract
We find that women who grew up under legal divorce have lower earnings and income and worse health as adults compared with women who grew up under illegal divorce. These negative effects are not found for men.

Father Absence and Reproductive Strategy: An Evolutionary Perspective: http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1037&context=anthropologyfacpub
interesting fact: father-absent childhood raises verbal and lowers math/spatial aptitude

Relation of Type and Onset of Father Absence to Cognitive Development: http://sci-hub.tw/http://www.jstor.org/stable/1127548
gender  causation  study  parenting  regularizer  long-term  developmental  environmental-effects  biodet  natural-experiment  confounding  sociology  org:ngo  intervention  endo-exo  multi  pdf  gender-diff  article  life-history  white-paper  meta-analysis  survey  education  labor  stress  psychiatry  dignity  endogenous-exogenous  sib-study  behavioral-gen  europe  nordic  psychology  social-psych  roots  variance-components  genetics  science-anxiety  chart  branches  cost-benefit  institutions  social-structure  health  demographics  compensation  policy  law  control  west-hunter  scitariat  anthropology  evopsych  sex  sexuality  rot  coming-apart  social-norms  stylized-facts  correlation  🌞  tradeoffs  class  sapiens  speculation  iq  language  spatial  psych-architecture  history  mostly-modern  data  comparison  personality  things  world-war  direction  cultural-dynamics  usa  higher-ed  harvard  phalanges  piracy  gnosis-logos  dirty-hands  embodied  the-world-is-just-atoms  cog-psych  intelligence 
august 2016 by nhaliday

bundles : abstractsp

related tags

:/  aaronson  ability-competence  absolute-relative  abstraction  academia  accuracy  acm  acmtariat  aDNA  adversarial  advice  africa  age-generation  aging  agri-mindset  agriculture  ai  albion  algorithms  alien-character  alignment  allodium  alt-inst  altruism  analogy  analysis  analytical-holistic  anglo  anglosphere  anthropic  anthropology  antidemos  antiquity  aphorism  apollonian-dionysian  applicability-prereqs  applications  arbitrage  arrows  art  article  asia  assortative-mating  atoms  attaq  attention  authoritarianism  axelrod  axioms  backup  bare-hands  bayesian  behavioral-gen  being-becoming  being-right  ben-recht  best-practices  better-explained  biases  big-list  big-peeps  big-picture  big-surf  bio  biodet  biophysical-econ  bits  blowhards  boltzmann  books  boolean-analysis  bostrom  bounded-cognition  brain-scan  branches  britain  broad-econ  calculation  canon  capitalism  career  cartoons  causation  characterization  chart  cheatsheet  checklists  china  christianity  civil-liberty  civilization  clarity  class  class-warfare  coalitions  coarse-fine  cocktail  coding-theory  cog-psych  cohesion  cold-war  coming-apart  commentary  communication  communism  comparison  compensation  competition  complement-substitute  complex-systems  composition-decomposition  compressed-sensing  computation  concentration-of-measure  concept  conceptual-vocab  concrete  conference  confidence  confounding  conquest-empire  consilience  constraint-satisfaction  context  contradiction  control  convexity-curvature  cool  cooperate-defect  coordination  correlation  cost-benefit  counter-revolution  courage  cracker-econ  creative  crime  criminology  CRISPR  critique  crooked  cultural-dynamics  culture  curiosity  current-events  curvature  cybernetics  cycles  cynicism-idealism  dark-arts  darwinian  data  data-science  database  death  debate  decision-making  deep-learning  deep-materialism  defense  definite-planning  definition  degrees-of-freedom  democracy  demographics  dennett  density  detail-architecture  developing-world  developmental  dignity  dimensionality  direct-indirect  direction  dirty-hands  discussion  disease  distribution  diversity  domestication  duplication  duty  dynamical  dysgenics  early-modern  earth  eastern-europe  ecology  economics  econotariat  eden  eden-heaven  education  EEA  egalitarianism-hierarchy  EGT  elections  electromag  elite  embeddings  embodied  empirical  ems  endo-exo  endocrine  endogenous-exogenous  ends-means  energy-resources  enhancement  enlightenment-renaissance-restoration-reformation  environment  environmental-effects  envy  epidemiology  equilibrium  error  essay  essence-existence  estimate  ethics  EU  europe  evolution  evopsych  examples  existence  exocortex  expansionism  expectancy  experiment  expert-experience  explanans  explanation  explore-exploit  exposition  farmers-and-foragers  fashun  features  fedja  fermi  fertility  fiction  field-study  fire  flexibility  flux-stasis  flynn  food  foreign-policy  formal-values  forms-instances  frontier  futurism  gallic  galor-like  garett-jones  gavisti  gedanken  gender  gender-diff  gene-drift  general-survey  generalization  generative  genetic-correlation  genetic-load  genetics  genomics  geoengineering  geography  geometry  germanic  giants  gibbon  gnon  gnosis-logos  gnxp  god-man-beast-victim  good-evil  gotchas  government  gowers  graphics  graphs  gravity  ground-up  group-selection  growth-econ  GWAS  gwern  hanson  hari-seldon  harvard  health  heuristic  hi-order-bits  hidden-motives  high-dimension  higher-ed  history  hive-mind  hmm  homo-hetero  homogeneity  honor  hsu  human-capital  humanity  humility  hypocrisy  hypothesis-testing  ideas  identity  identity-politics  ideology  idk  iidness  illusion  immune  impact  impetus  impro  incentives  increase-decrease  india  individualism-collectivism  industrial-org  inequality  inference  info-dynamics  infographic  information-theory  inner-product  innovation  insight  institutions  integrity  intel  intelligence  interdisciplinary  interests  intervention  intricacy  intuition  invariance  iq  iron-age  is-ought  isotropy  iteration-recursion  japan  jargon  kinship  knowledge  korea  kumbaya-kult  labor  language  large-factor  latent-variables  law  leadership  learning  learning-theory  lecture-notes  lectures  left-wing  legacy  lens  letters  levers  leviathan  lexical  life-history  lifts-projections  limits  linear-algebra  linear-programming  linearity  liner-notes  list  literature  logic  long-short-run  long-term  longevity  longitudinal  luca-trevisan  machiavelli  machine-learning  magnitude  malthus  manifolds  marginal  marginal-rev  markets  markov  martingale  matching  math  math.CA  math.CO  math.FA  math.GR  math.MG  mathtariat  matrix-factorization  meaningness  measure  measurement  mechanics  medicine  medieval  mediterranean  MENA  mental-math  meta-analysis  meta:math  meta:prediction  metabolic  metabuch  metameta  methodology  metric-space  metrics  microfoundations  migration  military  mit  ML-MAP-E  model-organism  models  moloch  moments  money  morality  mostly-modern  multi  multiplicative  murray  mutation  myth  n-factor  nationalism-globalism  natural-experiment  nature  navigation  near-far  network-structure  neuro  neuro-nitgrit  neurons  new-religion  news  nibble  nietzschean  nitty-gritty  nlp  noise-structure  nonlinearity  nordic  norms  novelty  number  objektbuch  occident  oceans  off-convex  open-problems  operational  optimism  optimization  order-disorder  orders  ORFE  org:bleg  org:data  org:econlib  org:edu  org:junk  org:mag  org:mat  org:med  org:nat  org:ngo  org:sci  organizing  orient  orwellian  oscillation  outcome-risk  overflow  paganism  paradox  parasites-microbiome  parenting  parsimony  paternal-age  path-dependence  patience  paying-rent  pdf  peace-violence  people  personality  pessimism  phalanges  phase-transition  philosophy  phys-energy  physics  pic  piracy  planning  play  plots  poast  policy  polisci  politics  poll  polynomials  pop-diff  popsci  population  population-genetics  power  pragmatic  pre-ww2  prediction  predictive-processing  preprint  priors-posteriors  privacy  probabilistic-method  probability  problem-solving  proofs  properties  property-rights  prudence  pseudoE  psych-architecture  psychiatry  psychology  psychometrics  public-goodish  q-n-a  QTL  quality  quantifiers-sums  questions  quotes  race  random  randy-ayndy  rant  rat-pack  rationality  ratty  realness  realpolitik  reason  recent-selection  recruiting  red-queen  reduction  reference  reflection  regression  regression-to-mean  regularization  regularizer  relativity  relaxation  religion  research  responsibility  retention  retrofit  review  revolution  rhetoric  right-wing  rigidity  rigor  rindermann-thompson  risk  robotics  robust  roots  rot  russia  s-factor  s:***  sampling  sanctity-degradation  sanjeev-arora  sapiens  scale  scholar  science  science-anxiety  scifi-fantasy  scitariat  search  sebastien-bubeck  selection  selfish-gene  separation  sex  sexuality  shannon  shift  short-circuit  sib-study  signal-noise  signaling  similarity  singularity  sinosphere  sky  slides  slippery-slope  social  social-choice  social-norms  social-psych  social-science  social-structure  sociology  socs-and-mops  soft-question  space  sparsity  spatial  spearhead  speculation  speed  speedometer  spengler  spock  spreading  stackex  stanford  stat-mech  state-of-art  stats  status  stereotypes  stochastic-processes  stock-flow  stories  strategy  straussian  street-fighting  stress  structure  study  studying  stylized-facts  subjective-objective  summary  survey  sv  symmetry  synchrony  synthesis  tactics  tails  talks  taxes  tcs  tcstariat  teaching  tech  technocracy  technology  telos-atelos  temperance  temperature  the-bones  the-classics  the-devil  the-great-west-whale  the-self  the-trenches  the-world-is-just-atoms  theory-of-mind  theory-practice  theos  thermo  thick-thin  things  thinking  threat-modeling  thurston  tidbits  tightness  time  time-preference  time-series  tip-of-tongue  tools  top-n  toxo-gondii  toys  track-record  tradeoffs  tradition  trees  trends  tribalism  tricki  tricks  trivia  truth  turing  twitter  uncertainty  unintended-consequences  uniqueness  universalism-particularism  urban-rural  us-them  usa  utopia-dystopia  vague  values  variance-components  video  virtu  visual-understanding  visuo  vitality  volo-avolo  war  wealth  wealth-of-nations  weird  west-hunter  westminster  white-paper  whole-partial-many  wiki  wire-guided  wisdom  within-group  within-without  wonkish  wordlessness  world  world-war  wormholes  worrydream  writing  xenobio  yoga  zeitgeist  🌞  🎓  👳  🔬  🤖 

Copy this bookmark:



description:


tags: