10 ms·

Baseline pupil size related to cognitive ability in proper lighting conditions

61 points by Teever 2y ago

sgt 2y ago
Pupil sizes also vary per race (with blacks having smaller pupils, aboriginals etc probably much smaller, who know). Race is of course a non scientific construct. Now someone might take this and "prove" that cognitive ability for certain groups are less than other groups. This is often why scientists shy away from this kind of thing.
- dotancohen 2y ago
  > Race is of course a non scientific construct. If I can observe that the ancestry of two people have a specific shape nose, certain hair colour range, and a typical range of heights different from the members of two other bloodlines, and then make predictions about how would appear the offspring of both, then how is that not scientific? I am aware that race is a contentious topic for USians, but I don't live in the US, so please assume good intentions and understand that I am asking to understand your viewpoint, not challenge it.
  - huimang 2y ago
    Deciding when features diverge enough to be a difference "race" is entirely arbitrary, and is largely for political reasons not scientific ones. The wikipedia articles on it are actually pretty good reading: https://en.wikipedia.org/wiki/Race_and_society https://en.wikipedia.org/wiki/Race_and_society Reading about historical classifications like the One drop rule shows how laughably arbitrary it is: https://en.wikipedia.org/wiki/One-drop_rule https://en.wikipedia.org/wiki/One-drop_rule
    - PKop 2y ago
      >features You're referencing extremes to argue against the concept entirely which is absurd. DNA can identify groups of people with similar clusters of genes that make up a race with high accuracy. It's tracing the lineage of you and your ancestors which isn't arbitrary, and most people are sufficiently more than a drop of a given race making the delineation quite clear.
      - huimang 2y ago
        Deciding that those "clusters of genes" represent an entirely different race is arbitrary, and it's not "clear" at all. Tracing DNA of ancestors has little to do with that. Please read the articles I linked, they're long but address your concerns.
    - exitb 2y ago
      I was watching the Olympics opening ceremony with my young son and he noticed that, at least in some cases, people from particular countries share a skin color. Was I supposed to tell him that he's mistaken and we indeed don't know why that appears to happen? Yes, races can mix which also mixes their features, making them difficult to singularly classify. But is it necessary to not notice that in some cases larger populations have not mixed for a while and developed a common set of features?
      - scotty79 2y ago
        You should explain to him that when people live in certain places for many generations some adaptations to local environment happen in their bodies. Then you could explain how it's a fairly recent thing that skin of some people got white because of living in relatively low light environment for millenia. As people now have have ability to move freely and freely eat food from around the globe this artifact of being stuck in one place will eventually disappear. But for now we can enjoy how differently people can look while being generally the same.
        dotancohen 2y ago
        > some adaptations to local environment happen in their bodies That is an excellent description of how different races came to diverge, thank you! I especially like that it emphasizes our common ancestry - we are all human.
        gregjor 2y ago
        A good explanation of how and why specific combinations of genes get concentrated in relatively isolated populations. What we call “race” historically got based on superficial features, not analysis of similarities in DNA. It turns out that sometimes those correspond, and sometimes they don’t. Indonesians and Brazilians have similar ranges of skin color (melanin) for the same reason — adaptation to sun exposure — but only distant common ancestors and very different histories.
        2y ago
  - sgt 2y ago
    I mean the categories that have been selected, are absolutely ridiculous. There isn't just one "black", as much as there is one "white". Imagine the differences in two white races at their most extremes: iranians and finns. Or slavs. Or irish. And blacks - are Khoisan black? If they are, they are extremely different from Nigerians, which again is an extremely ethnically diverse country. This is why I seriously dislike the categories selected by politicians and administrators.
    - deleted 2y ago
      [deleted]
    - dotancohen 2y ago
      > I mean the categories that have been selected, are absolutely ridiculous. There isn't just one "black", as much as there is one "white". Alright, so American popular conception of race is incorrect, not the concept of race as a whole. In my country we do not refer to black and white, we use the names that each racial group calls themselves (Beduin, Arab, Ethiopian, Moroccan, etc).
      - jampekka 2y ago
        I think OP's point is that it's arbitrary and context dependent where the line between races is drawn. It also includes non-genetic cultural traits, as in your example. Should a different eye color detemine a race demarcation? Is e.g. religion a factor in detemining a race? The examples you listed are probably better described as ethnic groups, which are not genetically detemined, not necessarily mutually exclusive and quite vaguely defined.
        dotancohen 2y ago
        I probably conflate race and ethnic group. In Hebrew we use the word גזע gez'a for both. What exactly is the difference?
  - jaggederest 2y ago
    Well, individual variation within what is broadly categorized as "races" exceeds the variation between "races" in aggregate, so the whole idea is nonsense. The vast majority of human genetic diversity is found in people with medium-to-dark skin color. To take an empirical equivalent, imagine if someone gave you two lists of people, one of whom was "tall", and the other was "short". And you measured the tall and short people, and there were people in the "short" group who were taller than average for the "tall" group, and vice versa. Their height as compared by means and standard deviations didn't vary substantially. At that point, your assumption should be that the labeling and grouping was wrong. So too for grouping people by skin color or many other arbitrary groupings like ethnic groups and national origin. That being said, there are groupings of people by genetic traits and things like that do matter - the classic example being broad African-American susceptibility to certain genetic-influenced illnesses like diabetes and heart disease. These are markers that more recent African immigrants don't show, and are likely a result of strong genetic and epigenetic selection for certain kinds of robustness as a result of the historical conditions they were subject to, i.e. slavery, discrimination, and poverty.
    - bun_terminator 2y ago
      Different metrics of variation. Members of races obviously have genetic properties in common.
    - throwaway9917 2y ago
      During the slave trade, most Africans that were brought to the Americas were from a fairly small area in West Africa. These days, African immigrants come from all over Africa. There is more human genetic variation within Africa than in the rest of the world combined. Parsimoniously it could just be that these West Africans were just more disposed to diabetes and heart disease than Africans as a whole.
    - PKop 2y ago
      >so the whole idea is nonsense In the last 11 Olympics, men with Sub-Saharan African ancestry have earned 87 of 88 finalist berths in the 100m dash. Is this random chance or does race correlate with some genetic traits enabling differentiation in physical abilities? >grouping people by skin color or many other arbitrary groupings This isn't arbitrary, when common ancestry and origin impart real world observable differences in a repeatable predictable way. >there are groupings of people by genetic traits and things like that do matter Yea exactly.
  - bnjemian 2y ago
    Here's the thing you may be missing: The complete diversity of human phenotypes (including what is socially discussed as 'race') is almost entirely present on the African continent. If you believe in evolution (and I'm assuming pretty much everyone here does), that makes a whole lot of sense – humans migrated out of Africa millenia ago and, as they moved to different environments, preferential selection for certain traits that already existed within the migrating population(s) occurred. There may be some traits that are beneficial and passed on due to spontaneous mutations post-migration, but they are relatively few and typically present in superficial features (e.g. eye color, hair color).
    - dotancohen 2y ago
      Your argument seems to support the notion of race, not counter it. Italy builds many classes of cars. We still classify them as luxury vehicles, sports vehicles, economy vehicles, etc. even if some parts are interchangable. The Lamborghini Diablo used passenger bus taillights.
  - energy123 2y ago
    We can draw conceptual borders between any two things, that doesn't automatically make those categories "scientific". Something being "scientific" has the implication that is has explanatory usefulness or predictive validity beyond the tautological ability to predict the definitions used to construct the categories. A taxonomy of humans based on statistical clusters of genotypes might be a scientific way to approach race/ethnicity, but subjectively chosen phenotypes is not it.
  - scotty79 2y ago
    One thing you should consider is that genetic diversity is highest between people in Africa. So two Africans who look the same to you might be more genetically different than European from Asian. In this sense race is not really scientific. Because it doesn't reflect general genetic similarity or diversity but rather a very small subset that's intersection of adaptions to local environment and things that are easily visible just by looking at someone.
    - dotancohen 2y ago
      African is not a race, but Haduo and Tigre are. If you are lumping them together into "African", then I agree that _your_ notion of race is wrong. But not the concept as a whole.
      - scotty79 2y ago
        Ask a random passerby if they ever heard about Haduo or Tigre races. Then ask them again if they heard about Black or White race. You can't make general claims based on how you understand the words.
  - Earw0rm 2y ago
    Genetic inheritance is different to the social construct of race ("black","white" etc). Bloodline is best avoided as a concept where humans are concerned, because the human gene pool was and is highly mobile. "Racial purity" is an idiot concept, and to the extent it has been attempted in humans, as with dogs it mostly leads to deformities and genetic diseases. (That Proclaimers song - "... and I would walk 500 miles" - turns out to be an order-of-magnitude underestimate of how far the 99th percentile will walk to get laid - and on a timescale of centuries/millennia, it's the 99th percentile that matters). And remember that in the US (and, for example, South Africa), that social construct extended to become a _legal_ construct used to discriminate against those designated as black. Most of Europe doesn't share that unhappy recent history (although we have our own, of course), it's hard to appreciate just how much more contentious it is in the US than Europe.
  - tidenly 2y ago
    The variance for most traits is higher within races than it is between them. I assume OPs point is the division into categories "black, white, asian, latino" is arbitrary, and you could easily reduce or add more groups as you see fit. Theres nowhere in science you can look that will tell you how many groups there are and where to draw the lines between them - i.e a construct. From an also non-USian.
    - dotancohen 2y ago
      I agree that the pseudo races that you mentioned are quite arbitrary, but I suppose they could be useful terms in a population as the diverse the US. In less mixed contexts such as Ethiopia nobody is "Black" rather they would be called one of the 300 some odd races they have there. Likewise in China - nobody's "Asian" in China, rather they are Han or something. There's probably a whole Venn diagram or tree to describe different races, how far up the tree we go to describe someone pretty much depends on how far away we are from them on that tree. And then there are people of mixed race - we are all human after all.
- bnjemian 2y ago
  I don't know if this is true – that pupil sizes vary meaningfully between races and folks from Africa and Aboriginal populations in Australia have smaller pupils – but it may make sense. Those are both relatively sunny places; Northern latitudes are less so. Greater dilation (or dynamic range around the dilation), more light, possibly improving certain aspects of vision in low light. Of course, the inverse may also hold – less ability for pupils to constrict in very sunny places would be problematic too. And yet, I say this knowing that hypotheses derived from first principles and uninformed of biological context tend to be very low mileage in the biological sciences. Biology is rarely so simple.
- gwervc 2y ago
  > Race is of course a non scientific construct. For a non scientific concept it's surprising very highly predictive. Somehow, when I was living in Japan, every Japanese could guess I was a foreigner without me saying anything! For some strange reason that also happened to my Nigerian friend. I wish science could investigate this phenomenon and give it a name...
  - gregjor 2y ago
    We do have a name for it: foreigner. Meaning not from around here, and ancestors not from around here either. In a homogenous population like Japanese the distinction seems trivial to observe. In Europe or the USA, with more heterogenous populations “foreigners” get harder to identify, and race gets based on superficial features rather than heritage. More than one stupid American politician has called out Spanish or Chinese speakers as foreigners even though their ancestors go as far back in the US as most caucasians. I once worked with a Nigerian woman who bristled and complained when our HR manager referred to her as “African American,” the politically correct term. Yetunde insisted on Nigerian, wanting no association with African Americans. Not the same race to her. That people around the world have very different definitions and boundaries when it comes to “race” tells you that it’s a social construct. [Before someone corrects me, I know Japanese doesn’t really describe a homogenous population or ancestry from a handful of ancient ancestors. Japanese only seem homogenous relative to the US and Europe. I live in east Asia among people who don’t see other “Asians” as members of the same race.]
csydas 2y ago
Maybe I am just not familiar enough with the subject to get the point, but this article doesn't really seem to focus on their actual claim but instead it's about explaining why no one else could reproduce their findings? I'm also still very confused on what the actual relationship is purported to be, at least based on this article. How did they determine cognitive ability here? I'm extremely wary of claims like the title, especially this one, as it seems like something children on a playground would say and use to bully each other, and certainly I imagine that many people will use it to justify being awful to others that are perceived to be "lesser" because of the rather outrageous title of the article, the article which I still really don't get how they're even making these connections to draw such a conclusion.
- ggm 2y ago
  "Focus on the actual claim" I see what you did there
- tgv 2y ago
  > How did they determine cognitive ability here? A few tests, among which specific memory tests. However, the memory tests didn't correlate, they claim only "fluid intelligence" correlates (even though they've also claimed the two are correlated). Fluid intelligence was measured "with the Raven’s Advanced Progressive Matrices, letter sets, and number series." The problem, for me, is that there is nothing to relate intelligence (fluid or otherwise) and pupil size. Without something plausible linking the two, this is just meaningless. And of course they rely on NHST statistics and a whole raft of modeling techniques, which is enough to call the whole article in doubt. I dare say they used very visual tasks, which may be harder for people with small pupils under less than optimal lighting conditions.
  - zrm 2y ago
    > The problem, for me, is that there is nothing to relate intelligence (fluid or otherwise) and pupil size. Without something plausible linking the two, this is just meaningless. Catecholamines: https://en.wikipedia.org/wiki/Catecholamine https://en.wikipedia.org/wiki/Catecholamine They're both neurotransmitters and vasoconstrictors, but the latter effect is reversed in the pupils, so they dilate your pupils. If you're low on catecholamines then your working memory is impaired and your pupils will be smaller. This is why amphetamine dilates your pupils and is prescribed to treat ADHD.
renewiltord 2y ago
This suspiciously seems like how cars that have yellow brake calipers go faster.
- dotancohen 2y ago
  That is mimicry of what was once an actual indicator. Brembo brakes calipers were famously coloured, and those were added by people who modify their cars to go faster. Mimicry won. As with many other metrics, once something becomes a metric it no longer accurately measures what it was intended to measure.
  - WWLink 2y ago
    The brembos on our cadillac are silver, and by modern standards it definitely is not a fast car lol. It sure stops nicely though.
    - dotancohen 2y ago
      Might I guess that your Cadillac is a relatively heavy luxury vehicle, and thus another class of vehicle that requires improved braking ability?
smokel 2y ago
Before you check yourself in the mirror, note that the article suggests that your pupil size should be larger for improved intelligence, not smaller, which is probably, but not scientifically "proven" to align with cunningness and shrewdness.
fraboniface 2y ago
This could explain why we naturally perceive and talk about an empty gaze or intelligent eyes. We all have a sense that someone's eyes somehow give a clue about their intelligence. Perhaps we're just inconsciously looking at pupil size.
- colordrops 2y ago
  My experience is it's more about how the eyes are used, e.g. what is being looked at, how focused they are on something, or when they intentionally unfocus their eyes, and the subtle rapid movements that indicate thought. Pupil size may factor in as well though.
  - tdullien 2y ago
    My father had a brain hemorrhage 2 years ago and now dementia. Watching the only video I have of him pre accident, there is a very marked difference in eye movements.
lokimedes 2y ago
Tangential reflection: Little known fact: SMILE eye surgery only allows pupils up to a fixed diameter. Kind of like car seats are also designed for a standard height individual. Interesting non-linear effects arise in low-light conditions when pupils dilate beyond the 6 mm maximum. Apparently being intelligent (and likely needing eye correction from all that reading) as well as tall, is no fun combination. The hard life of a multi-variate outlier in the world of average ergonomics.
- WWLink 2y ago
  lol the plus side is not needing the awful eye dialation eye drops when you see the optometrist!
- kwhitefoot 2y ago
  > likely needing eye correction from all that reading Is reading actually proven to cause short sightedness? I read everything I could lay my hands on from the age of four. From age ten I read at at least two hundred pages a day until I was in my thirties. I still don't need glasses at the age of nearly sixty nine. I realize that this is only one data point but I also know a lot of people who do need glasses and most of them are not and never have been avid readers. But I spent a large amount of time out of doors tramping the fields, especially in the summer. I still do spend at least an hour out of doors every day.
  - matthewdgreen 2y ago
    Apparently two hours per day of outdoor time for children has a huge impact [1]. Taiwan even has a government program to promote this among schoolkids. [1] https://www.npr.org/sections/health-shots/2024/05/13/1250555639/kids-eyesight-myopia-near-sighted-nearsightedness-outdoor-play https://www.npr.org/sections/health-shots/2024/05/13/1250555...
tom_j7 2y ago
[dead]
deleted 2y ago
[deleted]
m00x 2y ago
Fluid intelligence tests are already incredibly unreliable, and this study isn't particularly well done. It's an interesting concept, but I don't feel like the authors defend the hypothesis very well.
- dmichulke 2y ago
  I have difficulties finding anything related to, e.g., CFT and unreliability. Can you suggest an article or overview where this is discussed?
- dimask 2y ago
  What is not well done in this study?
  - michaelt 2y ago
    Running your intelligence study in the college's psychology building, paying participants in course credits? Calling Raven's Progressive Matrices, a measure of "reasoning about novel problems" when it's far from novel in psychology, and most of your test subjects are psychology students?
    - Y_Y 2y ago
      See also: https://rationalwiki.org/wiki/WEIRD https://rationalwiki.org/wiki/WEIRD By the way, I think they mean that Raven's Matrices test (somehow) for an ability to reason about problems that are new to the test subject, not that the test itself is new.
    - bitshiftfaced 2y ago
      I bet computer science majors have more of an "unfair" advantage than psych majors. It was hard not to notice how many of the patterns match bit manipulation rules such as not and xor.
- scotty79 2y ago
  What's unreliable about them? I thought that's one of the easiest things in psychology to repeatably measure.
amarant 2y ago
I wish I could go back in time and show this study to all those cops who stopped me and asked why my pupils were so large when I was a teenager. They suspected I was high (which where I live is illegal, even if you only have it in your blood). I'm just intelligent, thankyouverymuch!
- hyperhello 2y ago
  Same here, living in Southern California in the late nineties and being stopped all the time with that crap. But eventually you stop respecting the police and your real intelligence catches up with your perceived amount.
- jozvolskyef 2y ago
  I don't have much experience with the police, but almost every drug dealer gets excited the instant we make eye contact.
dartharva 2y ago
Needs a (2021) tag in the title. Also, F** ScienceDirect: https://sci-hub.se/https://doi.org/10.1016/j.cognition.2021.104643 https://sci-hub.se/https://doi.org/10.1016/j.cognition.2021....
water9 2y ago
People who take Drugs like heroin Have really small pupils whereas people that take drugs like cocaine have very large pupils. It might not necessarily be fluid intelligence at play but rather Stimulation and adequate sleep biasing the results
- Earw0rm 2y ago
  This. Pupil size correlates with stimulation level, which in turn correlates with attention and performance. And it's not a simple one-way street - drugs of course have an effect (caffeine, for a start) - but psychological factors also come into play - someone who is more able to activate their attention in response to a task will likely show a physiological response. Your pupils will "pop" in response to both pleasant (sexually attractive person) and unpleasant (unexpected large tax bill) tasks or stimuli, but the amount by which they do so is going to vary from one pair of (background conditions, situation) to the next.
Simon_ORourke 2y ago
Pupil size maybe, but those poor unfortunate folks with eyes spaced too closely together unfairly appear to be cognitively challenged. Like my former CEO, looked dumb, folks instinctively underestimated him and he always came out on top in deals.
nis0s 2y ago
This relates to the idea that vision loss can also impact brain function https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8739068/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8739068/ I think the underlying mechanism is related to neuron activation in the brain itself because it’s possible that more visual stimulation, regardless of being involved in the task at hand, helps with cognitive functioning in some manner. There are some interesting questions remaining to explore here, like would direct neuron stimulation bypass the pupil size role.
thro1 2y ago
preprint pdf: https://osf.io/pvz24/download/ https://osf.io/pvz24/download/ poster.pdf: https://osf.io/qhjpm https://osf.io/qhjpm

61 points by Teever 2y ago

sgt 2y ago

Pupil sizes also vary per race (with blacks having smaller pupils, aboriginals etc probably much smaller, who know). Race is of course a non scientific construct. Now someone might take this and "prove" that cognitive ability for certain groups are less than other groups. This is often why scientists shy away from this kind of thing.

dotancohen 2y ago
> Race is of course a non scientific construct. If I can observe that the ancestry of two people have a specific shape nose, certain hair colour range, and a typical range of heights different from the members of two other bloodlines, and then make predictions about how would appear the offspring of both, then how is that not scientific? I am aware that race is a contentious topic for USians, but I don't live in the US, so please assume good intentions and understand that I am asking to understand your viewpoint, not challenge it.
- huimang 2y ago
  Deciding when features diverge enough to be a difference "race" is entirely arbitrary, and is largely for political reasons not scientific ones. The wikipedia articles on it are actually pretty good reading: https://en.wikipedia.org/wiki/Race_and_society https://en.wikipedia.org/wiki/Race_and_society Reading about historical classifications like the One drop rule shows how laughably arbitrary it is: https://en.wikipedia.org/wiki/One-drop_rule https://en.wikipedia.org/wiki/One-drop_rule
  - PKop 2y ago
    >features You're referencing extremes to argue against the concept entirely which is absurd. DNA can identify groups of people with similar clusters of genes that make up a race with high accuracy. It's tracing the lineage of you and your ancestors which isn't arbitrary, and most people are sufficiently more than a drop of a given race making the delineation quite clear.
    - huimang 2y ago
      Deciding that those "clusters of genes" represent an entirely different race is arbitrary, and it's not "clear" at all. Tracing DNA of ancestors has little to do with that. Please read the articles I linked, they're long but address your concerns.
  - exitb 2y ago
    I was watching the Olympics opening ceremony with my young son and he noticed that, at least in some cases, people from particular countries share a skin color. Was I supposed to tell him that he's mistaken and we indeed don't know why that appears to happen? Yes, races can mix which also mixes their features, making them difficult to singularly classify. But is it necessary to not notice that in some cases larger populations have not mixed for a while and developed a common set of features?
    - scotty79 2y ago
      You should explain to him that when people live in certain places for many generations some adaptations to local environment happen in their bodies. Then you could explain how it's a fairly recent thing that skin of some people got white because of living in relatively low light environment for millenia. As people now have have ability to move freely and freely eat food from around the globe this artifact of being stuck in one place will eventually disappear. But for now we can enjoy how differently people can look while being generally the same.
      - dotancohen 2y ago
        > some adaptations to local environment happen in their bodies That is an excellent description of how different races came to diverge, thank you! I especially like that it emphasizes our common ancestry - we are all human.
        gregjor 2y ago
        A good explanation of how and why specific combinations of genes get concentrated in relatively isolated populations. What we call “race” historically got based on superficial features, not analysis of similarities in DNA. It turns out that sometimes those correspond, and sometimes they don’t. Indonesians and Brazilians have similar ranges of skin color (melanin) for the same reason — adaptation to sun exposure — but only distant common ancestors and very different histories.
        2y ago
- sgt 2y ago
  I mean the categories that have been selected, are absolutely ridiculous. There isn't just one "black", as much as there is one "white". Imagine the differences in two white races at their most extremes: iranians and finns. Or slavs. Or irish. And blacks - are Khoisan black? If they are, they are extremely different from Nigerians, which again is an extremely ethnically diverse country. This is why I seriously dislike the categories selected by politicians and administrators.
  - deleted 2y ago
    [deleted]
  - dotancohen 2y ago
    > I mean the categories that have been selected, are absolutely ridiculous. There isn't just one "black", as much as there is one "white". Alright, so American popular conception of race is incorrect, not the concept of race as a whole. In my country we do not refer to black and white, we use the names that each racial group calls themselves (Beduin, Arab, Ethiopian, Moroccan, etc).
    - jampekka 2y ago
      I think OP's point is that it's arbitrary and context dependent where the line between races is drawn. It also includes non-genetic cultural traits, as in your example. Should a different eye color detemine a race demarcation? Is e.g. religion a factor in detemining a race? The examples you listed are probably better described as ethnic groups, which are not genetically detemined, not necessarily mutually exclusive and quite vaguely defined.
      - dotancohen 2y ago
        I probably conflate race and ethnic group. In Hebrew we use the word גזע gez'a for both. What exactly is the difference?
- jaggederest 2y ago
  Well, individual variation within what is broadly categorized as "races" exceeds the variation between "races" in aggregate, so the whole idea is nonsense. The vast majority of human genetic diversity is found in people with medium-to-dark skin color. To take an empirical equivalent, imagine if someone gave you two lists of people, one of whom was "tall", and the other was "short". And you measured the tall and short people, and there were people in the "short" group who were taller than average for the "tall" group, and vice versa. Their height as compared by means and standard deviations didn't vary substantially. At that point, your assumption should be that the labeling and grouping was wrong. So too for grouping people by skin color or many other arbitrary groupings like ethnic groups and national origin. That being said, there are groupings of people by genetic traits and things like that do matter - the classic example being broad African-American susceptibility to certain genetic-influenced illnesses like diabetes and heart disease. These are markers that more recent African immigrants don't show, and are likely a result of strong genetic and epigenetic selection for certain kinds of robustness as a result of the historical conditions they were subject to, i.e. slavery, discrimination, and poverty.
  - bun_terminator 2y ago
    Different metrics of variation. Members of races obviously have genetic properties in common.
  - throwaway9917 2y ago
    During the slave trade, most Africans that were brought to the Americas were from a fairly small area in West Africa. These days, African immigrants come from all over Africa. There is more human genetic variation within Africa than in the rest of the world combined. Parsimoniously it could just be that these West Africans were just more disposed to diabetes and heart disease than Africans as a whole.
  - PKop 2y ago
    >so the whole idea is nonsense In the last 11 Olympics, men with Sub-Saharan African ancestry have earned 87 of 88 finalist berths in the 100m dash. Is this random chance or does race correlate with some genetic traits enabling differentiation in physical abilities? >grouping people by skin color or many other arbitrary groupings This isn't arbitrary, when common ancestry and origin impart real world observable differences in a repeatable predictable way. >there are groupings of people by genetic traits and things like that do matter Yea exactly.
- bnjemian 2y ago
  Here's the thing you may be missing: The complete diversity of human phenotypes (including what is socially discussed as 'race') is almost entirely present on the African continent. If you believe in evolution (and I'm assuming pretty much everyone here does), that makes a whole lot of sense – humans migrated out of Africa millenia ago and, as they moved to different environments, preferential selection for certain traits that already existed within the migrating population(s) occurred. There may be some traits that are beneficial and passed on due to spontaneous mutations post-migration, but they are relatively few and typically present in superficial features (e.g. eye color, hair color).
  - dotancohen 2y ago
    Your argument seems to support the notion of race, not counter it. Italy builds many classes of cars. We still classify them as luxury vehicles, sports vehicles, economy vehicles, etc. even if some parts are interchangable. The Lamborghini Diablo used passenger bus taillights.
- energy123 2y ago
  We can draw conceptual borders between any two things, that doesn't automatically make those categories "scientific". Something being "scientific" has the implication that is has explanatory usefulness or predictive validity beyond the tautological ability to predict the definitions used to construct the categories. A taxonomy of humans based on statistical clusters of genotypes might be a scientific way to approach race/ethnicity, but subjectively chosen phenotypes is not it.
- scotty79 2y ago
  One thing you should consider is that genetic diversity is highest between people in Africa. So two Africans who look the same to you might be more genetically different than European from Asian. In this sense race is not really scientific. Because it doesn't reflect general genetic similarity or diversity but rather a very small subset that's intersection of adaptions to local environment and things that are easily visible just by looking at someone.
  - dotancohen 2y ago
    African is not a race, but Haduo and Tigre are. If you are lumping them together into "African", then I agree that _your_ notion of race is wrong. But not the concept as a whole.
    - scotty79 2y ago
      Ask a random passerby if they ever heard about Haduo or Tigre races. Then ask them again if they heard about Black or White race. You can't make general claims based on how you understand the words.
- Earw0rm 2y ago
  Genetic inheritance is different to the social construct of race ("black","white" etc). Bloodline is best avoided as a concept where humans are concerned, because the human gene pool was and is highly mobile. "Racial purity" is an idiot concept, and to the extent it has been attempted in humans, as with dogs it mostly leads to deformities and genetic diseases. (That Proclaimers song - "... and I would walk 500 miles" - turns out to be an order-of-magnitude underestimate of how far the 99th percentile will walk to get laid - and on a timescale of centuries/millennia, it's the 99th percentile that matters). And remember that in the US (and, for example, South Africa), that social construct extended to become a _legal_ construct used to discriminate against those designated as black. Most of Europe doesn't share that unhappy recent history (although we have our own, of course), it's hard to appreciate just how much more contentious it is in the US than Europe.
- tidenly 2y ago
  The variance for most traits is higher within races than it is between them. I assume OPs point is the division into categories "black, white, asian, latino" is arbitrary, and you could easily reduce or add more groups as you see fit. Theres nowhere in science you can look that will tell you how many groups there are and where to draw the lines between them - i.e a construct. From an also non-USian.
  - dotancohen 2y ago
    I agree that the pseudo races that you mentioned are quite arbitrary, but I suppose they could be useful terms in a population as the diverse the US. In less mixed contexts such as Ethiopia nobody is "Black" rather they would be called one of the 300 some odd races they have there. Likewise in China - nobody's "Asian" in China, rather they are Han or something. There's probably a whole Venn diagram or tree to describe different races, how far up the tree we go to describe someone pretty much depends on how far away we are from them on that tree. And then there are people of mixed race - we are all human after all.
bnjemian 2y ago
I don't know if this is true – that pupil sizes vary meaningfully between races and folks from Africa and Aboriginal populations in Australia have smaller pupils – but it may make sense. Those are both relatively sunny places; Northern latitudes are less so. Greater dilation (or dynamic range around the dilation), more light, possibly improving certain aspects of vision in low light. Of course, the inverse may also hold – less ability for pupils to constrict in very sunny places would be problematic too. And yet, I say this knowing that hypotheses derived from first principles and uninformed of biological context tend to be very low mileage in the biological sciences. Biology is rarely so simple.
gwervc 2y ago
> Race is of course a non scientific construct. For a non scientific concept it's surprising very highly predictive. Somehow, when I was living in Japan, every Japanese could guess I was a foreigner without me saying anything! For some strange reason that also happened to my Nigerian friend. I wish science could investigate this phenomenon and give it a name...
- gregjor 2y ago
  We do have a name for it: foreigner. Meaning not from around here, and ancestors not from around here either. In a homogenous population like Japanese the distinction seems trivial to observe. In Europe or the USA, with more heterogenous populations “foreigners” get harder to identify, and race gets based on superficial features rather than heritage. More than one stupid American politician has called out Spanish or Chinese speakers as foreigners even though their ancestors go as far back in the US as most caucasians. I once worked with a Nigerian woman who bristled and complained when our HR manager referred to her as “African American,” the politically correct term. Yetunde insisted on Nigerian, wanting no association with African Americans. Not the same race to her. That people around the world have very different definitions and boundaries when it comes to “race” tells you that it’s a social construct. [Before someone corrects me, I know Japanese doesn’t really describe a homogenous population or ancestry from a handful of ancient ancestors. Japanese only seem homogenous relative to the US and Europe. I live in east Asia among people who don’t see other “Asians” as members of the same race.]

csydas 2y ago

Maybe I am just not familiar enough with the subject to get the point, but this article doesn't really seem to focus on their actual claim but instead it's about explaining why no one else could reproduce their findings? I'm also still very confused on what the actual relationship is purported to be, at least based on this article. How did they determine cognitive ability here? I'm extremely wary of claims like the title, especially this one, as it seems like something children on a playground would say and use to bully each other, and certainly I imagine that many people will use it to justify being awful to others that are perceived to be "lesser" because of the rather outrageous title of the article, the article which I still really don't get how they're even making these connections to draw such a conclusion.

ggm 2y ago
"Focus on the actual claim" I see what you did there
tgv 2y ago
> How did they determine cognitive ability here? A few tests, among which specific memory tests. However, the memory tests didn't correlate, they claim only "fluid intelligence" correlates (even though they've also claimed the two are correlated). Fluid intelligence was measured "with the Raven’s Advanced Progressive Matrices, letter sets, and number series." The problem, for me, is that there is nothing to relate intelligence (fluid or otherwise) and pupil size. Without something plausible linking the two, this is just meaningless. And of course they rely on NHST statistics and a whole raft of modeling techniques, which is enough to call the whole article in doubt. I dare say they used very visual tasks, which may be harder for people with small pupils under less than optimal lighting conditions.
- zrm 2y ago
  > The problem, for me, is that there is nothing to relate intelligence (fluid or otherwise) and pupil size. Without something plausible linking the two, this is just meaningless. Catecholamines: https://en.wikipedia.org/wiki/Catecholamine https://en.wikipedia.org/wiki/Catecholamine They're both neurotransmitters and vasoconstrictors, but the latter effect is reversed in the pupils, so they dilate your pupils. If you're low on catecholamines then your working memory is impaired and your pupils will be smaller. This is why amphetamine dilates your pupils and is prescribed to treat ADHD.

renewiltord 2y ago

This suspiciously seems like how cars that have yellow brake calipers go faster.

dotancohen 2y ago
That is mimicry of what was once an actual indicator. Brembo brakes calipers were famously coloured, and those were added by people who modify their cars to go faster. Mimicry won. As with many other metrics, once something becomes a metric it no longer accurately measures what it was intended to measure.
- WWLink 2y ago
  The brembos on our cadillac are silver, and by modern standards it definitely is not a fast car lol. It sure stops nicely though.
  - dotancohen 2y ago
    Might I guess that your Cadillac is a relatively heavy luxury vehicle, and thus another class of vehicle that requires improved braking ability?

smokel 2y ago

Before you check yourself in the mirror, note that the article suggests that your pupil size should be larger for improved intelligence, not smaller, which is probably, but not scientifically "proven" to align with cunningness and shrewdness.

fraboniface 2y ago

This could explain why we naturally perceive and talk about an empty gaze or intelligent eyes. We all have a sense that someone's eyes somehow give a clue about their intelligence. Perhaps we're just inconsciously looking at pupil size.

colordrops 2y ago
My experience is it's more about how the eyes are used, e.g. what is being looked at, how focused they are on something, or when they intentionally unfocus their eyes, and the subtle rapid movements that indicate thought. Pupil size may factor in as well though.
- tdullien 2y ago
  My father had a brain hemorrhage 2 years ago and now dementia. Watching the only video I have of him pre accident, there is a very marked difference in eye movements.

lokimedes 2y ago

Tangential reflection: Little known fact: SMILE eye surgery only allows pupils up to a fixed diameter. Kind of like car seats are also designed for a standard height individual. Interesting non-linear effects arise in low-light conditions when pupils dilate beyond the 6 mm maximum. Apparently being intelligent (and likely needing eye correction from all that reading) as well as tall, is no fun combination. The hard life of a multi-variate outlier in the world of average ergonomics.

WWLink 2y ago
lol the plus side is not needing the awful eye dialation eye drops when you see the optometrist!
kwhitefoot 2y ago
> likely needing eye correction from all that reading Is reading actually proven to cause short sightedness? I read everything I could lay my hands on from the age of four. From age ten I read at at least two hundred pages a day until I was in my thirties. I still don't need glasses at the age of nearly sixty nine. I realize that this is only one data point but I also know a lot of people who do need glasses and most of them are not and never have been avid readers. But I spent a large amount of time out of doors tramping the fields, especially in the summer. I still do spend at least an hour out of doors every day.
- matthewdgreen 2y ago
  Apparently two hours per day of outdoor time for children has a huge impact [1]. Taiwan even has a government program to promote this among schoolkids. [1] https://www.npr.org/sections/health-shots/2024/05/13/1250555639/kids-eyesight-myopia-near-sighted-nearsightedness-outdoor-play https://www.npr.org/sections/health-shots/2024/05/13/1250555...

tom_j7 2y ago

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m00x 2y ago

Fluid intelligence tests are already incredibly unreliable, and this study isn't particularly well done. It's an interesting concept, but I don't feel like the authors defend the hypothesis very well.

dmichulke 2y ago
I have difficulties finding anything related to, e.g., CFT and unreliability. Can you suggest an article or overview where this is discussed?
dimask 2y ago
What is not well done in this study?
- michaelt 2y ago
  Running your intelligence study in the college's psychology building, paying participants in course credits? Calling Raven's Progressive Matrices, a measure of "reasoning about novel problems" when it's far from novel in psychology, and most of your test subjects are psychology students?
  - Y_Y 2y ago
    See also: https://rationalwiki.org/wiki/WEIRD https://rationalwiki.org/wiki/WEIRD By the way, I think they mean that Raven's Matrices test (somehow) for an ability to reason about problems that are new to the test subject, not that the test itself is new.
  - bitshiftfaced 2y ago
    I bet computer science majors have more of an "unfair" advantage than psych majors. It was hard not to notice how many of the patterns match bit manipulation rules such as not and xor.
scotty79 2y ago
What's unreliable about them? I thought that's one of the easiest things in psychology to repeatably measure.

amarant 2y ago

I wish I could go back in time and show this study to all those cops who stopped me and asked why my pupils were so large when I was a teenager. They suspected I was high (which where I live is illegal, even if you only have it in your blood). I'm just intelligent, thankyouverymuch!

hyperhello 2y ago
Same here, living in Southern California in the late nineties and being stopped all the time with that crap. But eventually you stop respecting the police and your real intelligence catches up with your perceived amount.
jozvolskyef 2y ago
I don't have much experience with the police, but almost every drug dealer gets excited the instant we make eye contact.

dartharva 2y ago

Needs a (2021) tag in the title. Also, F** ScienceDirect: https://sci-hub.se/https://doi.org/10.1016/j.cognition.2021.104643 https://sci-hub.se/https://doi.org/10.1016/j.cognition.2021....

water9 2y ago

People who take Drugs like heroin Have really small pupils whereas people that take drugs like cocaine have very large pupils. It might not necessarily be fluid intelligence at play but rather Stimulation and adequate sleep biasing the results

Earw0rm 2y ago
This. Pupil size correlates with stimulation level, which in turn correlates with attention and performance. And it's not a simple one-way street - drugs of course have an effect (caffeine, for a start) - but psychological factors also come into play - someone who is more able to activate their attention in response to a task will likely show a physiological response. Your pupils will "pop" in response to both pleasant (sexually attractive person) and unpleasant (unexpected large tax bill) tasks or stimuli, but the amount by which they do so is going to vary from one pair of (background conditions, situation) to the next.

Simon_ORourke 2y ago

Pupil size maybe, but those poor unfortunate folks with eyes spaced too closely together unfairly appear to be cognitively challenged. Like my former CEO, looked dumb, folks instinctively underestimated him and he always came out on top in deals.

nis0s 2y ago

This relates to the idea that vision loss can also impact brain function https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8739068/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8739068/ I think the underlying mechanism is related to neuron activation in the brain itself because it’s possible that more visual stimulation, regardless of being involved in the task at hand, helps with cognitive functioning in some manner. There are some interesting questions remaining to explore here, like would direct neuron stimulation bypass the pupil size role.

thro1 2y ago

preprint pdf: https://osf.io/pvz24/download/ https://osf.io/pvz24/download/ poster.pdf: https://osf.io/qhjpm https://osf.io/qhjpm