[HN Gopher] Averaging is a convenient fiction of neuroscience
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Averaging is a convenient fiction of neuroscience
Author : domofutu
Score : 100 points
Date : 2024-09-23 21:41 UTC (1 days ago)
(HTM) web link (www.thetransmitter.org)
(TXT) w3m dump (www.thetransmitter.org)
| glial wrote:
| All models are convenient fictions. I heard a neuroscientist once
| describe averaging as a low-pass filter. People know it hides
| high-frequency dynamics. But unless you have a way to interpret
| the high-frequency signal, it looks an awful lot like noise.
| sroussey wrote:
| I think of summaries as the text equivalent of averaging. Some
| high frequency stuff you don't want to loose in that case are
| things like proper names, specific dates, etc. In the face of
| such signal, you don't want to average it out to a "him" and a
| "Monday".
| datameta wrote:
| That would be a median in your example no? A spurious average
| might be us thinking that the statistical mean word contains
| all vowels except for 'e', and that 'm' is twice as likely as
| the other most likely consonants.
| bitwize wrote:
| That makes a lot of sense. Thank you for this analogy.
|
| We use Conscrewence at work for internal documentation, and
| when I pull a page up it wants to recommend an AI-generated
| summary for me. Uh, no, Atlassian, I'm on this page _because_
| I want _all_ the details!
| heyitsguay wrote:
| My grad school research was with an NIH neuroscience lab
| studying low-level sensory processing that offered a
| fascinating perspective on what's really going on there! At
| least for the first few levels above the sense receptors in
| simpler animal models.
|
| To oversimplify, you can interpret gamma-frequency activity as
| chunking up temporal sensory inputs into windows. The specific
| dynamics between excitatory and inhibitory populations in a
| region of the brain create a gating mechanism where only a
| fraction of the most stimulated excitatory neurons are able to
| fire, and therefore pass along a signal downstream, before
| broadly-tuned inhibitory feedback silences the whole population
| and the next gamma cycle begins. Information is transmitted
| deeper into the brain based on the population-level patterns of
| excitatory activity per brief gamma window, rather than being a
| simple rate encoding over longer periods of time.
|
| Again, this is an oversimplification, not entirely correct,
| fails to take other activity into account etc etc, but I'm
| sharing it as an example of an extant model of brain activity
| that not only doesn't average out high-frequency dynamics, but
| explicitly relies on them in a complex nonlinear fashion to
| model neural activity at the population level at high temporal
| frequency in a natural way. And it's not completely abstract,
| you can relate it to observed population firing patterns in,
| e.g., insect olfactory processing, now the we have the hardware
| to make accurate high-frequency population recordings.
| robwwilliams wrote:
| By "low level" do you mean in the thalamus or cortex or
| something else. Live a citation. I initially thought that
| "low level" meant at the level of receptors and the first few
| synapses. But to the best of my knowledge gamma oscillations
| will not play a roll in the periphery.
|
| It would be great if you had a citation. I have been reading
| Karl Friston's work all day.
| glial wrote:
| Here's an example[1] examining the functional role of gamma
| oscillations in the hippocampus:
|
| [1] https://www.jneurosci.org/content/15/1/47
| jtrueb wrote:
| It is a low-pass filter in the frequency domain with a roll-off
| that is not smooth. I quite like [1] as a quick reference.
|
| https://www.analog.com/media/en/technical-documentation/dsp-...
| etrautmann wrote:
| Not the OP but we're talking about different things here.
| Much of the concern about averaging is about averaging across
| trials. Smoothing a spike train over time isn't really the
| issue that this thread is concerned with, since that's just
| averaging successive samples within some small window.
| datameta wrote:
| In physics the model we choose is based on the scale - as in
| the macro sense all quantum effects average out over the
| several sextillion atoms in, say, a wood screw.
| ggm wrote:
| > _But unless you have a way to interpret the high-frequency
| signal, it looks an awful lot like noise._
|
| In other words, they're looking for their lost keys under the
| lamp-post because it's easier there. If there is a signal in
| the HF, it's not yet understood. This feels like "junk DNA"
| -which is I believe receiving more attention than the name
| suggests.
| JumpCrisscross wrote:
| > _they 're looking for their lost keys under the lamp-post
| because it's easier there_
|
| This is a strange criticism. If you're looking for your keys
| in the dead of night, and there is a lamp post where they
| might be, you _should_ start there.
|
| The streelight effect criticises " _only_ search[ing] for
| something where it is easiest to look " [1]. Not searching
| where it's easiest in all cases.
|
| In this case, we know averaging destroys information. But we
| don't know to what significance. As the author says, "we now
| have the tools we need to find out if averaging is showing us
| something about the brain's signals or is a misleading
| historical accident." That neither confirms nor damns the
| preceding research--it may be that averaging is perfectly
| fine, hides some of the truth that we can now uncover or is
| entirely misleading.
|
| [1] https://en.wikipedia.org/wiki/Streetlight_effect
| ggm wrote:
| Good point.
| etrautmann wrote:
| This is broadly speaking not correct. If you average together a
| bunch of trials with variable timing, then the result can tend
| to wash out higher frequency components (which you might not
| have realized were in the data), but trial averaging is not a
| low pass filter at all. There are some nice methods to recover
| temporal structure that changes across trials prior to
| averaging, like:
|
| https://www.sciencedirect.com/science/article/pii/S089662731...
| UniverseHacker wrote:
| I've become increasingly convinced that the idea of averaging is
| one of the biggest obstacles to understanding things... it
| contains the insidious trap of feeling/sounding "rigorous" and
| "quantitative" while making huge assumptions that are extremely
| inappropriate for most real world situations.
|
| Once I started noticing this I can't stop seeing this almost
| everywhere- almost every news article, scientific paper, etc.
| will make clearly inappropriate inferences about a phenomenon
| based on the exact same mistake of confusing the average for a
| complete description of a distribution, or a more nuanced
| context.
|
| Just a simple common example, is the popular myth that ancient
| people died of old age in their 30s, based on an "average life
| span of ~33 years" or such. In reality the modal life expectancy
| of adults (most common age of death other than 0) has been pretty
| stable in the 70s-80s range for most of human history- the low
| average was almost entirely due to infant mortality.
|
| The above example is a case where thinking in terms of averages
| causes you to grossly misunderstand simple things, in a way that
| would be impossible even with basic common sense in a person that
| had never encountered the idea of math... yet it is a mistake you
| can reliably expect people in modern times to make.
| KK7NIL wrote:
| I think you'd enjoy this video on different types of means and
| their applications: https://youtube.com/watch?v=V1_4nNm8a6w
| mcmoor wrote:
| It's just trying to assume normal distribution when it's not
| normal. Modern science rely so much on that distribution that i
| actually whether they have overestimated its ubiquity just
| because it's so damn convenient to use.
| Jweb_Guru wrote:
| While it is true that not all distributions are normal, many
| distributions are approximately normal (or at least, normal
| in some sensible space that maps onto the actual collected
| data). IMO the amount of ink spilled on the idea that science
| is fundamentally flawed because distributions aren't always
| normal is probably too high (especially among non-
| statisticians), and frankly that's not where statistical
| analyses usually go wrong. A much larger problem (that has
| nothing to do with the ultimate shape of the distribution) is
| stuff like postselecting from a set of plausible models until
| you find one that finds significant results, and claiming
| that was what you intended to measure all along ( _this_ is
| why it 's important to consider stuff like hyperpriors, much
| moreso than lack of normality).
| UniverseHacker wrote:
| Yes, this is the actual issue- assuming a normal distribution
| in cases that are not normally distributed. People also even
| leave off the standard deviation, and seem to be mentally
| thinking of the average as a point rather than considering
| even the "width" of the normal distribution- so the
| overemphasis of the average even causes people to
| misunderstand things that really are normally distributed.
| hinkley wrote:
| Averages are very bad in bimodal distributions.
|
| And that includes issues of public policy, where going left
| sort of works, and going right sort of works, and going in the
| middle sucks for absolutely everyone.
| JumpCrisscross wrote:
| > _Averages are very bad in bimodal distributions_
|
| They're bad with multimodal distributions, generally, as well
| as any random process governed by a distribution with no
| mean, _e.g._ Cauchy [1].
|
| (Neuronal firing appears to be non-Gaussian, possibly
| lognormal [2], which _does_ have a mean [3], but it isn 't
| equal to the simple average.)
|
| [1]
| https://en.wikipedia.org/wiki/Cauchy_distribution#Properties
|
| [2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6633220/
|
| [3] https://en.wikipedia.org/wiki/Log-normal_distribution
| bosma wrote:
| > In reality the modal life expectancy of adults (most common
| age of death other than 0) has been pretty stable in the
| 70s-80s range for most of human history- the low average was
| almost entirely due to infant mortality.
|
| This isn't true: https://ourworldindata.org/its-not-just-about-
| child-mortalit...
| Spooky23 wrote:
| It mostly is. The biggest gains are in childhood. Aldo
| consider that you're looking at figures for England and
| Wales, which isn't necessarily representative.
|
| The largest contribution to improving life expectancy is
| measured by reductions in child mortality. The factors that
| drove those improvements (infection control, improved
| hygienic practices, food quality, regulation of food and drug
| purity, medicine) benefited everyone, but had the biggest
| impact on the old and young. In the 1850s, _8,000_ infants
| died _annually_ from adulterated milk alone.
|
| I think of my own journey. In 1824, 200 year ago Spooky23
| would have died 20 years ago, a half blind cripple. 2024
| Spooky23 is healthy with no back issues and god willing a few
| more decades.
| JumpCrisscross wrote:
| > _It mostly is. The biggest gains are in childhood._
|
| The life expectancy of a 60-year old going from 74.4 to 84,
| or a 70-year old from 79.1 to 85.9, is significant and
| meaningful. Not as much as a newborn's LE going from 41.6
| to 81.1. But far from "pretty stable in the 70s-80s range
| for most of human history."
|
| Also, recent life-expectancy increases have come from adult
| morality reductions [1].
|
| [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3000019/
| UniverseHacker wrote:
| How are "74.4 to 84" and "79.1 to 85.9" "pretty far from"
| the "70s-80s range"?
|
| > adult morality reductions
|
| LOL
| llm_trw wrote:
| From the nice graph at:
| https://ourworldindata.org/images/published/Life-
| expectancy-...
|
| In 1850 a 0 year old would expect to live to 41.6 years. A
| 5 year old would expect to live to 55.2.
|
| If we waved a magic wand and let all infants survive past
| childhood with nothing else changed in 1850 life expectancy
| would still be 27 years lower than it is today. Or put
| another way you'd have the same life expectancy as someone
| in South Sudan or Somalia.
| Spooky23 wrote:
| Sounds like we mostly agree, save some pedantry.
|
| Nobody waved a wand. The contaminated milk that killed
| infants killed adults too - alcohol and milk were
| alternatives to unsafe water. Public health, medicine and
| other factors improved things.
|
| We don't really have great stats from before the 19th
| century. Was 1850 a nadir in life expectancy? I'm not
| sure - but I suspect it varied by region and rural/urban
| conditions. 1750 NYC wasn't as gross as 1850.
| llm_trw wrote:
| >Sounds like we mostly agree, save some pedantry.
|
| If by pedantry you mean that I'm not ignoring the cause
| of 70% of the improvement in life expectancy in the last
| 200 years then sure.
| Jweb_Guru wrote:
| Indeed, this conversation is a good illustration of the
| damage that Bayesian statistics have done to the
| "educated" populace. Not that they're inherently bad--
| it's just a different statistical approach, and it's
| generally good not to assume a universal background, that
| everything is normal, etc.--but by telling people it's
| fine to question statistical conclusions because the
| distribution might be different, it liberates certain
| people from ever having to actually change their minds
| based on new information, because they can just posit a
| different distribution that satisfies their own biases.
| UniverseHacker wrote:
| I realize this is a bit of a "no true Scotsman" but what
| you are talking about is a gross misuse of Bayesianism-
| where your own biases are incorrectly treated as
| extremely strong evidence.
|
| I am partial to using unform priors over all
| possibilities, and then just adding in the actual
| evidence for which you can actually quantify its
| quality/strength. Your "prior" for a new situation is
| constructed by applying the data you already had
| previously to a uniform prior- not by fabricating it from
| whole cloth via your biases. In practice this may be
| impossible for humans to do in their heads, but computers
| certainly can!
| UniverseHacker wrote:
| What I was saying is in reference to this study, which
| suggests a modal life span of about 72 years of age in the
| paleolithic: https://onlinelibrary.wiley.com/doi/10.1111/j.17
| 28-4457.2007...
| usednoise4sale wrote:
| Our world in data pushes a clear agenda, and it isn't really
| to be trusted.
|
| Consider: https://ourworldindata.org/child-mortality-in-the-
| past
|
| From this article: "Researchers also collected data about
| hunter-gatherer societies. The 17 different societies include
| paleolithic and modern-day hunter-gatherers and the mortality
| rate was high in all of them. On average, 49% of all children
| died.[5]"
|
| This is cited as coming from: https://www.sciencedirect.com/s
| cience/article/abs/pii/S10905...
|
| Which categorically states: "Unfortunately there simply is
| not enough direct paleodemographic archaeological data to
| make definite claims about the global patterns of infant and
| child mortality rates of our Paleolithic hunter-gatherer
| ancestors."
|
| The author of the Our World in Data piece seemingly
| intentionally conflates the proxy with actual archaeological
| evidence of the actual child mortality rates. Given the clear
| warning in the cited article about making definite claims, I
| cannot read the deception any other way.
|
| After seeing this error, I do not know how you could possibly
| trust anything they have to say on the matter.
| llm_trw wrote:
| >In reality the modal life expectancy of adults (most common
| age of death other than 0) has been pretty stable in the
| 70s-80s range for most of human history- the low average was
| almost entirely due to infant mortality.
|
| This is even wronger than what you critique.
|
| For every period in history that we have good data for people
| had a half-life - a period in which you'd expect half of all
| people to die:
| https://batintheattic.blogspot.com/2011/07/medieval-populati...
|
| For example in medieval Germany it looked something like:
| | Age | Half-life | | 0-10 | 10 | |
| 10-20 | 40 | | 20-40 | 20 | |
| 40-80 | 10 |
|
| It's called a population pyramid not a population column for a
| reason.
|
| The exact age varies by location, but even if we ignore
| everyone under 10, half of all people left would still die
| before they are 40.
| JumpCrisscross wrote:
| > _if we ignore everyone under 10, half of all people left
| would still die before they are 40_
|
| Wouldn't it be 50 since the half-life is an interval?
| llm_trw wrote:
| No, the half life for age 10-20 is much higher than that
| for 20-40 and the exponential function is non-linear.
| UniverseHacker wrote:
| What you said in no way conflicts with what I said. For
| example, if people have dangerous lives in a way that is
| unconnected to age they will tend to not live long, yet the
| modal life expectancy due to the additional mortality of
| actual old age can still be quite old.
|
| What I was saying is in reference to this study I read long
| ago, which suggests a modal life span of about 72 years of
| age in the paleolithic: https://onlinelibrary.wiley.com/doi/1
| 0.1111/j.1728-4457.2007...
| llm_trw wrote:
| >What you said in no way conflicts with what I said.
|
| Neither would a world with 88 people with the following
| death schedule. | Age | Deaths/Year |
| |---------+-------------| | 0 to 5 | 2 |
| | 5 to 70 | 1 | | 70 | 3 |
|
| I'm sure that the 3 people who make it to 70 are very happy
| they are in the highest mode of the distribution. The 85
| who did not may have something to say about how meaningful
| using the mode of a distribution is.
| UniverseHacker wrote:
| It's the right thing to use in this specific context not
| because it is explaining the full picture better than the
| average, but because it distorts the picture in a
| different way: the modal age being high is incompatible
| with the incorrect assumption people are making when
| seeing a low average life span- that people in ancient
| times basically never made it to an old age in their 70s
| or older. People then jump from that to the idea that
| people were dying of old age much younger, which isn't
| accurate... they were mostly dying of things unrelated to
| aging, and few were making it to old age- but healthy
| active people in their 80s and older did exist even in
| ancient times, and are mostly more common now because our
| lives are safer.
|
| Deeper than that, I think there is a modern tendency to
| want to believe false claims about how awful life was in
| the past, and how much better we have it now... so there
| are a large number of such myths that are nearly
| ubiquitous but not accurate. Not to say that many aren't
| also accurate, just that the inaccurate ones go largely
| unquestioned.
|
| Modern times are very different from most of human
| history- better in many ways and worse in many others. If
| we romanticize how perfect the present is, we then lose
| the ability to make things still better.
| llm_trw wrote:
| >because it distorts the picture in a different way: the
| modal age being high is incompatible with the incorrect
| assumption people are making when seeing a low average
| life span- that people in ancient times basically never
| made it to an old age in their 70s or older.
|
| I literally proved by demonstration why having a
| distribution with an absolute mode in the extreme most
| value means that 97% of people still died younger than
| that. There is nothing wrong with the assumption that
| basically no one made it to 70 because less than 0.5% of
| people actually did for any period where we have records.
|
| >Deeper than that, I think there is a modern tendency to
| want to believe false claims about how awful life was in
| the past, and how much better we have it now... so there
| are a large number of such myths that are nearly
| ubiquitous but not accurate. Not to say that many aren't
| also accurate, just that the inaccurate ones go largely
| unquestioned.
|
| Again, you're wronger than the people who hold that view.
| I'm not sure what you're arguing against at this point
| other than sophistry.
| UniverseHacker wrote:
| Neither of us are wrong per se- we are saying different
| things that are fully compatible with one another, but
| are both incomplete. However, I am using a biased model
| on purpose while aware of its limitations, and you seem
| to be confusing yours with reality, which is why mine
| seems "wrong" to you- because my model is specifically
| being used to show where yours does not fit reality.
| Looking at mode alone is pretty useless other than to
| make this one point, I think it is important to emphasize
| that I do not think it is somehow better than the
| improper use of averages I was criticizing, or that it
| should be generally used in the same way averages
| generally are.
|
| What I am saying is important to me because I'm
| interested specifically in what health and life were like
| for those few people that made it to old age in ancient
| times - to see how it might provide ideas to improve our
| health today. For example, I have found that I need a
| huge amount of exercise and natural light or else I feel
| fatigued and depressed... I felt I "should not" need
| this, until I realized not getting this is some sort of
| anomaly in human history- and there is no reason to
| expect everyone to be able to handle low levels of light
| and activity.
|
| Reading about "evolutionary medicine" theorizing was so
| fascinating it led me to get my doctorate and become an
| academic PI, although my research is not really in that
| area these days, I still find it interesting and useful
| as a hypothesis generator and not "anti science" as
| another person on here accused me of.
| UniverseHacker wrote:
| I wanted to add- in general if you make a simple
| calculation or model of some real phenomena, such as
| taking the mean, median, or mode of a real set of data-
| and the conclusions you then draw from each are
| fundamentally incompatible, then you made a mistake
| somewhere in drawing those conclusions.
|
| The replies to my original comment are basically mostly
| people making this same category of mistake and arguing
| which is "correct" - the average or the mode of the same
| distribution. Unfortunately, I chose a really bad example
| where people already hold strong almost religious or
| political opinions, rather than something generic that
| just illustrates the math.
| authorfly wrote:
| The paper he linked though isn't a distribution where the
| age 72 is a special modal number. The paper suggests
| 68-78 is the adaptive lifespan for some small
| communities.
| wodenokoto wrote:
| Parent is talking about mode, so the most common number.
| Let's build a distribution that satisfy both.
|
| Oldest age is set 80, mode is set to 75. We start by
| distribution one percentage point to each age. Then add an
| extra to the mode and all the remaining to zero.
|
| We now have a distribution where the most common age of
| death, other than zero be in 70-80, and more than half the
| population die before they reach 40.
| SkyBelow wrote:
| Is there an issue with how the data is grouped? At 19.9, you
| have a 50% chance of living to 59.9. But less than a season
| later at 20.1, you now only have a 50% chance o living to
| 40.1. How can the former be right if the latter is right?
|
| The growth in life expectancy from surviving early childhood
| makes sense, but the decline in life expectancy for crossing
| 20 feels too sharp.
| Mistletoe wrote:
| I was at the Denver museum's mummy exhibit and disturbed to see
| that they said the lady died at 30, a "normal age for death in
| those times". You would think a museum should know better.
|
| https://aeon.co/ideas/think-everyone-died-young-in-ancient-s...
| orwin wrote:
| Half the people died before 40 in the middle ages,
| discounting pre-5 mortality. I would assume it is lower for
| female, as first pregnancies had a 10% mortality rate (this
| rate increased after the middle age, until germ theory), and
| following ones carried a 2-5% mortality rates.
| UniverseHacker wrote:
| Great article that pretty well explains the situation with
| modern vs ancient life expectancy.
| ddfs123 wrote:
| > In reality the modal life expectancy of adults (most common
| age of death other than 0) has been pretty stable in the
| 70s-80s range for most of human history-
|
| I am pretty sure this is wrong. East Asian cultures celebrate
| 60th birthday as becoming very elderly, and if you live to the
| 70s it's almost as if you achieved Buddhahood.
| JumpCrisscross wrote:
| Your beef appears to be with simple averages, not averaging
| _per se_.
|
| The average for life expectancy is the mean of the Gompertz
| distribution [1]. Specifically, one that is "left skewed and
| with a flattened slope for ages under 50 years for men and 60
| years for women," which proceeds to become "more right skewed
| and leptokurtic" as age increases [2].
|
| So a simple average in the <55 domain would underestimate the
| mean while in the >55 domain it would overestimate it. Which is
| almost comically problematic when comparing ancient societies
| that had a median age below that level to modern ones above it.
|
| > _the modal life expectancy of adults (most common age of
| death other than 0) has been pretty stable in the 70s-80s range
| for most of human history_
|
| Not quite. 63 in 1900 to 83 in 2000 (in Sweden). Bigger
| differences when you go further back.
|
| [1] https://en.wikipedia.org/wiki/Gompertz_distribution
|
| [2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2652977/
|
| [3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3000019/
| _Figure 1_
| UniverseHacker wrote:
| What I was saying is in reference to this study, which
| suggests a modal life span of about 72 years of age in the
| paleolithic: https://onlinelibrary.wiley.com/doi/10.1111/j.17
| 28-4457.2007...
|
| Life spans were abnormally short in medieval Europe, even
| compared to ancient humans.
| dalmo3 wrote:
| I came to the same realisation about a decade ago, after being
| a "science" enthusiast growing up. As you said once you see it
| you can't unsee it. Most of science is just a scam. The
| exceptions are those fields backed up by real world
| engineering. All of social and most of biological sciences are
| worse than useless, they are outright dangerous.
| hifromwork wrote:
| >Most of science is just a scam
|
| Most of the scientists are not scammers. So if you believe
| that all science disciplines other than engineering are
| wrong[1], you should use another word that doesn't suggest
| researcher malice.
|
| [1]Which is a very strong statement, because you claim to be
| an expert in all science disciplines at once.
| zmgsabst wrote:
| I think there's clear evidence that a sizable portion of
| "science" is indeed a scam for prestige and funding.
|
| https://en.wikipedia.org/wiki/Replication_crisis
| tourmalinetaco wrote:
| At minimum the social and even a fair bit of medical
| science are scams, as they rarely have enough evidence to
| definitively draw claims due to a mixture of flawed
| methodology, small sample sizes, and lack of additional
| studies to reinforce their claims. See for instance the
| claim every man makes at some point, that "going braless
| makes breasts perkier". Small sample size that isn't
| indicative of all breast sizes/shapes, few if any studies
| supporting their findings. At least with engineering
| experimentation is far easier, can be extrapolated, and can
| even be simulated reliably.
|
| And no, one does not claim to be "an expert in all
| disciplines at once" by pointing out the objective fact
| that we lack concrete data in a lot of fields.
| UniverseHacker wrote:
| I think you are overreaching with that. Science at its core
| is curious and open minded problem solving combined with an
| anti-authoritarian skepticism- you accept things once you can
| understand and confirm them for yourself. Ideally, it is also
| Bayesian- e.g. considering all of the evidence, even weak
| evidence like personal anecdotes, while correctly keeping
| track of how strong or weak each bit of evidence really is.
|
| You have the courage to trust what you understand deeply even
| if other powerful authorities disagree- and take the
| responsibility to make sure you do actually understand deeply
| (the conspiracy theory crowd is missing the second bit). As a
| practicing academic scientist, I feel like the vast majority
| of my colleagues with research focused academic careers also
| see it this way.
|
| Nearly everything called "science" in popular culture
| (including school science classes, pop science books, etc.)
| is actually a sort of dogmatic religion that idolizes
| science. One of the weirdest things for me, is coming on here
| and when I share the type of creative thinking that actually
| leads scientists to new hypotheses, I am insulted and accused
| of being an "idiot" or "anti-science" by mostly career
| programmers for whom science is a religion, and not a
| creative process. When they talk to a scientist, they see
| someone that doesn't align with their fixed dogmatic views,
| and label it as basically the opposite of what they are
| actually encountering- real science looks like
| "pseudoscience" to them. These people would even attack
| someone like Isaac Newton as an idiot for daring to discuss
| something new that seems "weird" and idolize, e.g. a medical
| doctor repeating some old official stance from an institution
| that has been thoroughly disproven by new research.
| ants_everywhere wrote:
| Yeah it's a common mistake, but this is like intro to stats
| stuff. It's not some big secret that if you summarize a
| distribution with a single number then you've lost information.
|
| > I've become increasingly convinced that the idea of averaging
| is one of the biggest obstacles to understanding things.
|
| I'd counter that it's easily one of the biggest assistants in
| understanding things. The Central Limit Theorem in particular
| has been enormously influential. Without averaging statistical
| mechanics and thermodynamics would have been impossible and
| with them would go the industrial revolution.
|
| What you're noticing is one kind of mistake caused by lack of
| literacy in science. There are many many more similar mistakes.
| The solution isn't _less_ literacy.
| ithkuil wrote:
| > The solution isn't less literacy.
|
| This.
|
| It's interesting how a common instinct to seeing problems is
| way too often to "destroy and rebuild" instead of "correct
| and improve". "Institutions have failed us?" A) "Let's burn
| them down" vs B) "Let's have better institutions, keep what's
| good, fix what's bad"
|
| I get it that sometimes, rarely, it's impossible to improve
| something because it's soo rotten and entrenched that you
| literally have to destroy and rebuild from scratch, but it's
| almost never the case.
| UniverseHacker wrote:
| > this is like intro to stats stuff
|
| Amazing how the replies to my initial comment range from
| angrily calling me an idiot for saying something so obviously
| and egregiously wrong, to claiming it is so trivial and
| obvious that I should not have needed to mention it.
|
| > The solution isn't less literacy.
|
| Indeed, I can see how what I wrote could be taken that way, I
| also don't think so. The problem is combining an inadequate
| amount of literacy, with an almost religious belief in its
| absolute correctness, e.g. scientism.
| ants_everywhere wrote:
| To clarify, I'm not saying that it's trivial or obvious,
| just that it's fundamental. Just like derivatives aren't
| trivial or obvious but everyone who has taken Intro to
| Calculus knows about them.
|
| > "e.g. scientism"
|
| Isn't this just an anti-science term adopted by religious
| people and postmodernists?
| UniverseHacker wrote:
| > Isn't this just an anti-science term adopted by
| religious people and postmodernists?
|
| Not at all, as a scientist, I find scientism to be very
| common and the biggest obstacle to the general public
| understanding science- more so than religious people and
| postmodernists which are at least openly anti-science,
| rather than just confused about what it is. It is a
| fanatical religious like belief in the correctness,
| completeness, and finality of "what science has already
| discovered" and an aggressive dismissal of e.g. things
| like creative though experiments or anecdotal
| observations that question current understanding. To
| people practicing scientism, the regular practice of
| actual science looks like heresy and pseudo-science and
| they would get angry if they were present, e.g. when
| Isaac Newton or Charles Darwin first mentioned their now
| accepted but once controversial ideas. They will say
| things like you don't know (and shouldn't think or talk
| about) anything until it is confirmed in a large study-
| without considering how scientists come up with the
| designs and ideas (and funding) for such studies in the
| first place.
|
| Science in popular media and schools is taught as a bunch
| of authoritarian facts to memorize and believe without
| deeply and intuitively understanding, rather than a
| creative process of trying to deeply understanding and
| question things for yourself. When I mention something
| interesting or counter-intuitive I encountered in my
| professional research, or something interesting I have
| been thinking about recently- especially among young
| intelligent "skeptical and science loving" non-scientist
| programmers on this forum, I am often met with angry
| derision, because the process of talking about and
| exploring weird ideas- e.g. the actual how the sausage is
| made by working scientists, is seen as extremely
| unacceptable if it conflicts with what they heard in
| school, media, etc. I've mentioned things I've personally
| discovered on here- and been called an idiot and sent the
| wikipedia link for a field I've studied for decades, and
| is actually citing _my_ older papers and work, by someone
| that only heard the field existed when they read my
| comment.
|
| The pseudo-science conspiracy theory people ironically
| get the creative independent thinking part more right
| than the "Scientism-ists", but then miss the important
| second part of actually taking the responsibility to
| deeply understand for yourself, and critically question
| things.
|
| There is something very wrong with science education when
| the people that say they love it, respond negatively when
| they encounter the real thing- and this can be fixed by
| redesigning science education. As an academic PI I don't
| teach regular classes, but put students directly in the
| lab working on a new problem nobody has solved before,
| where they can't look up the answer, and then mentor them
| 1 on 1 if they get really stuck. I then have them
| actually write it up and submit it to a real peer
| reviewed journal.
| domofutu wrote:
| Averages can definitely oversimplify things, especially in
| neuroscience where outliers often tell the real story. Taleb
| touches on this in Antifragile--focusing too much on the
| average can make us miss what's happening at the edges, where
| the most interesting things are. Instead of leaning on
| averages, we might get more insight by paying attention to the
| extremes, where the real nuances are hiding.
| UniverseHacker wrote:
| Yes, I like Taleb's suggestion of considering a "fat tailed"
| Cauchy distribution- as to not assume extreme outliers can't
| exist
| UniverseHacker wrote:
| @ flagged aaron695:
|
| > The brutal reality is you don't have the IQ to understand
| averages or statistics like most people.
|
| > Most of our ancestors lucky enough to made it to 45 years old
| in human history did not make it to 70.
|
| > Using mode is misleading with "age", and you quickly showed
| you didn't understand 'the con' when you accidently tried to
| apply it.
|
| > This is a political, the "past was wonderful fantasy" which
| is anti-science. It's used by the Woke for instance."
|
| In this case I am using an equally "wrong" model on purpose
| while being well aware of its limitations, just to make a
| specific point. It highlights a point where people are doing
| exactly what you are accusing me of- romanticizing the present,
| and not understanding the reality of how it actually differs
| from the past. E.g. what are the actual reasons people had
| shorter life spans in the past, and what their lives were
| actually like. One should not forget the limitations of such a
| simple model, which was basically my point in the first place.
|
| I am fascinated by "evolutionary medicine" and using such ideas
| as a hypothesis generator to figure out ways to treat "modern
| diseases of civilization." I am in no way romanticizing the
| past, but trying to understand the specifics, to better figure
| out how to develop more effective modern day medical
| treatments, not to return to the past. In truth I despise
| political thinking altogether, and like to look at mechanisms
| and biological details.
|
| Your post smacks of "scientism" which is incompatible with
| actual practice of science. The very idea that a certain line
| of thinking or theorizing is "anti science" or should be taboo
| for political reasons is itself incompatible with creative open
| minded problem solving.
|
| I can see it was a mistake to use this specific example for
| discussing the problem with averages- ironically because it is
| so accurate. Since so many people on here hold the exact
| misunderstanding I was criticizing, they are getting angry and
| insulting me instead of my intent, which was to explain a
| phenomenon and have this click as a simple example of it. A
| less charged example, where people don't have strong opinions
| already would have been better.
| throw_pm23 wrote:
| I've heard this argument a million times, but I am very
| skeptical: where would the reliable data on infant mortality in
| ancient times come from? (so that it would allow us to compute
| precise values of average lifespan). All we have from those
| times are a few bone samples and a few anecdotes preserved in
| fragments.
|
| I'm not saying anything for or against the ~33 years claim,
| just that I doubt that it comes from a precise estimate of
| expected lifespan at birth.
| achierius wrote:
| > All we have from those times are a few bone samples and a
| few anecdotes preserved in fragments.
|
| This is the bit that you're missing: antiquity is generally
| considered to extend all the way into the 500-600s AD, with
| the Roman empire dominating its center and 'late antiquity'
| covering the whole early period of the Byzantine empire. This
| means that even just in Europe we have extensive documents
| (e.g. in the Christian era, baptism and burial records), as
| well as a wealth of burial evidence from which to extrapolate
| lifespans. If you look into the sources for Rome you'll find
| Egypt in particular come up a lot, which isn't an accident:
| the dry climate and extensive use of papyrus means that the
| region preserved far more records (and bodies) than any other
| part of the empire.
| nosianu wrote:
| In a Gresham College video lecture about microbial disease
| (if only I remembered the title...) the lecturing professor
| briefly mentions that in Victorian Britain life expectancy
| was actually "higher than today" when you exclude children
| and women (who had a great risk of death during pregnancy and
| birth).
|
| https://www.gresham.ac.uk/watch-now/return-microbes-how-
| infe...
|
| The video has a text with the words.
|
| Look for
|
| > _So, your life expectancy at five, in England, as a male,
| in 1870 was slightly longer than it is now, which is an
| extraordinary statistic, slightly shorter then if you were a
| female._
|
| 1870s Britain is not "ancient", but as far as medicine is
| concerned much closer to that than to modern times. What
| medicine there was wasn't even available to most people. They
| were pretty good with "physical" things like broken bones by
| then, but anything concerning microbes probably wasn't much
| better than what was done a thousand years earlier.
|
| Obviously, as you point out, we don't _have_ statistics from
| ancient times, only some hints, but that is the same for
| people making the claim about the short average life spans
| (without the little detail about infant and women mortality).
|
| There also is the question of how meaningful it is to average
| over vastly different sections of the population (what you
| did and how you lived and what you ate, access to good water,
| hygiene), or times of famine or war.
|
| Some related discussion, reddit, but the heavily moderated
| AskHistorians subreddit: https://www.reddit.com/r/AskHistoria
| ns/comments/12o4py/what_...
|
| There we see the lower life expectancy of early agricultural
| societies vs. hunter-gatherers (ignoring their high number of
| deaths due to violence).
|
| I think all of this also serves to illustrate OPs point about
| the problem of averages :-) There's just too much important
| information that is lost.
| bell-cot wrote:
| > In reality the modal life expectancy of adults (most common
| age of death other than 0) has been pretty stable in the
| 70s-80s range for most of human history- the low average was
| almost entirely due to infant mortality.
|
| Until the last few-ish generations, pregnancy and childbirth
| have been leading causes of death for women in those in-between
| decades of their lives.
|
| (And obviously War and Famine, too, for both genders.)
| KK7NIL wrote:
| Very interesting how measurement limitations drive scientific
| consensus.
|
| The author portrays this as a major flaw in neuroscience, but it
| seems like a natural consequence of Newton's flaming laser sword;
| why theorize about something that you can't directly measure?
| robwwilliams wrote:
| Great note Mark. I agree. Action potentials are noisy beasts but
| much may be hidden in spike time coding that is obscured by
| averaging.
|
| There is an even lower level problem that deserves more thought.
| What timebase do we use to average, or not. There is no handy
| oscillator or clock embedded in the cortex or thalamus that
| allows a neuron or module or us to declare "these events are
| synchronous and in phase".
|
| Our notions of external wall-clock time have been reified and
| then causally imposed on brain activity. Since most higher order
| cognitive decisions take more than 20 to 200 milliseconds of wall
| clock time it is presumptuous to assume any neuron is necessarily
| working in a single network or module. There could be dozens or
| hundreds of temporally semi-independent modules spread out over
| wall clock-time that still manage to produce the right motor
| output.
| RaftPeople wrote:
| > _There is no handy oscillator or clock embedded in the cortex
| or thalamus that allows a neuron or module or us to declare
| "these events are synchronous and in phase"._
|
| Brains waves drive synchronization of groups of neurons, lower
| frequencies broader, higher frequencies more localized.
| robwwilliams wrote:
| That is uncertain. They must be a product of underlying
| processes, but the mechanisms are still opaque.
|
| Gamma oscillations only run at about 40 Hz. That is not fast
| enough to clock neuronal computations or integrations in the
| 1 to 10 msec range.
|
| Oscillations may have role in binding at larger scales. And
| when we use the word "synchronize" we generally seem to mean
| "given wall-clock time".
|
| Two neural events separated by 20 msec can be functionally
| coherent but may neither be in a particular phase relation or
| concurrent from an observer's wall-clock perspective.
| Neuronal activity may not care about the observer's timebase.
| hinkley wrote:
| There's an old case study from aerospace that shows up sometimes
| in UX discussions, where the US military tried to design an
| airplane that fit the 'average' pilot and found that they made a
| plane that was not comfortable for _any_ pilots. They had to go
| back in and add margins to a bunch of things, so they were
| adjustable within some number of std deviations of 'average'.
| stonethrowaway wrote:
| They used those original average measurements to design seats
| for passengers instead.
| robertclaus wrote:
| As a computer scientist, I was blown away the first time my
| friend explained to me that his research focused on the timing of
| neuron spikes, not their magnitude. After talking about it for a
| while I realized that machine learning neural networks are much
| closer to simple early models of how neuron's work (averages and
| all), not how neuron's actually signal. Makes sense when you
| consider how the latest LLM models have almost as many parameters
| as we have neurons, but we still seem pretty far from AGI.
| dilawar wrote:
| In many, perhaps most, signalling pathways, amplitude doesn't
| matter much (it does at log-scale). Given how well we control
| temperature and therefore rate of the reaction, it makes sense
| to use timing to fight off the noise.
| llm_trw wrote:
| Put another way, there is a reason why FM radio sounds much
| better than AM radio.
|
| https://www.youtube.com/watch?v=AzvxefRDT84
| lamename wrote:
| Yes and no. An alternate perspective is that the output of each
| neuron in an artificial neural net is analogous to an F-I curve
| in a real neuron (spike frequency-input DC current curve). In
| this way, different neurons have different slopes and
| intercepts in their FI curves, just as a network of ANN neurons
| effectively have their activation functions tweaked after
| applying weights.
|
| I usually only say this to other neuroscientists who have a
| background in electrophysiology. The analogy isn't perfect, and
| is unnecessary to understand what ANNs are doing, but the
| analogy still stands.
| Nahtnah wrote:
| Eh, the analogy is farrr from perfect. You're basically
| assuming you can reduce neurons to LTI systems. Which you
| obviously very much cannot.
| giardini wrote:
| LTI=Linear Time Invariant
|
| https://en.wikipedia.org/wiki/Linear_time-invariant_system
| ithkuil wrote:
| An elephant brain has 3 times as many neurons as a human.
|
| They are pretty smart animals but so are dogs who have way less
| neurons. The point here being that the number of neurons is
| just one of the many factors that determines intelligence
| (general or not)
| smokel wrote:
| Even among humans with roughly similar neuron counts, there
| are notable examples of individuals displaying extreme
| stupidity.
| ithkuil wrote:
| To further complicate matters, some forms of stupidity are
| not the lack of intelligence but the consequence of other
| cognitive processes that may (or would) otherwise useful in
| social animals because they reinforce group bonds and have
| a role in group identity definition. Not all those
| processes are well adapted to the modern society.
| Ey7NFZ3P0nzAe wrote:
| 80% of human neurons are actually in the cerebellum and are
| not related to consciousness at all
| yberreby wrote:
| > the latest LLM models have almost as many parameters as we
| have neurons
|
| I often see this take, but the apt comparison is between
| parameter and _synapse_ count, not _neuron_ count. You should
| be counting hidden units rather than weights if you want to
| compare to neuron counts.
| markhahn wrote:
| I think you should compare synapse and weight counts if you
| want a measure of the network's state/capacity. If you want
| something closer to its compute power, compare neurons and
| hidden units.
| Bjartr wrote:
| To expand on that, as a point of comparison, a single neuron
| can have thousands of synaptic connections. So we're still a
| few orders of magnitude out from modeling NNs that have a
| degree of connectivity similar to the brain, even though the
| synapse counts are comparable.
| lamename wrote:
| There's even an artist that made this point: Cartoon Neuron
|
| https://www.redbubble.com/shop/ap/6229477
|
| https://x.com/Cartoon_Neuron
| personjerry wrote:
| Reminds me of "When U.S. air force discovered the flaw of
| averages" [0]
|
| [0]: https://www.thestar.com/news/insight/when-u-s-air-force-
| disc...
| richrichie wrote:
| There are even bigger problems. For example, the common "this
| region lights up more if this is done" type of fMRI studies are
| suspect because what the fMRI tool does may have no bearing to
| actual brain function. I read a book by a neuroscientist
| lamenting the abuses of fMRI in papers a while ago.
| Unfortunately, unable to locate the reference.
| 1659447091 wrote:
| Somewhat related book on how the concept of average can be
| misleading and/or detrimental, The End of Average
|
| https://search.worldcat.org/title/The-end-of-average-:-how-w...
| ithkuil wrote:
| There are three kinds of lies: lies, damned lies, and fake
| quotes.
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