4 ms·

It blows me away that people can see things like this and still deny any genetic basis for certain cognitive features in humans.

wizzwizz4 5y ago
Humans haven't had multiple generations of selective breeding to select for particular cognitive traits. We have, however, had: • Sunburn / vitamin D deficiency • Oxygen deprivation at high altitudes • Free diving which have had obvious effects on certain human populations. But mentally, we're all pretty much just human, same as any other; variation is massive, yes, but it can be pretty big between siblings. Seeing “sheep dog breeds have a herding instinct” doesn't tell you much about humans. When people try to argue a “genetic basis” for a particular trait, they're usually just trying to justify racism.
- newfriend 5y ago
  Exactly. Different populations of humans vary wildly by almost every physical trait, such as height, build, bone structure, skin, hair type, eye color, muscle fiber. But when it comes to the brain, we are all exactly the same.
  - sudosysgen 5y ago
    Muscle fiber variations across humans are pretty small. They're really only very noticeable as far as the extremes, or in quite small populations. Similarly, hair types are barely different. But to tell you a story, the village my ancestors lived in for centuries had people with smooth blond hair and people like me with extremely stiff black hair. Same for eye color. Anyways, I digress, these are generally single-gene variations which is why you will find most of the variation in most populations. Height and build is an interesting one. For most of history heights were very similar across populations. Actually, the only exception we know of were Anglo-Saxon settlers, and some peoples in South-East Asia. This suggests that people even in extremely remote places had incredibly similar evolutionary pressures that led to almost identical heights. But nowadays, the specificities of the impact on a changing diet are different [https://www.tandfonline.com/doi/abs/10.1080/20780389.2012.657489 https://www.tandfonline.com/doi/abs/10.1080/20780389.2012.65...]. Skin is really the biggest one, because Vitamin-D deficiency and skin cancer are huge evolutionary pressures. But as we've seen, otherwise it's pretty clear humans evolved in broadly similar environments and found very similar tradeoffs. This is especially true for intelligence where the biggest load for intelligence was social interactions, and where social structures are very similar.
- kokanator 5y ago
  I know people don't want to admit to genetic impacts on cognition but there have been pressures over many generations for these traits and those pressures have been different all over the world. Take the example of a genetic lineage living in a jungle where it is necessary to know the difference, availability, dietary qualities, medicinal aspects of thousands of plants. Not to mention predatory dangers, snake dangers, environmental dangers, etc. In this case, the individual with high aptitudes for memorization, categorization and pattern matching would survive at a substantially higher rate than those with lower aptitudes. Remember, a small band does not have the resources to support low producing members so they would not be artificially perpetuated.
  - wizzwizz4 5y ago
    No; the individual with high aptitudes for memorisation, categorisation and pattern-matching would become the local healing expert, likely apprenticed to whoever was best at it before. Everyone else would focus primarily on the predatory and environmental dangers, plus their own specialisms (and, you know, everything else). Remember: we live in a society. So did our ancestors. Intelligence is a pretty general skill; all sorts of different selection pressures push it up, not least of all interpersonal politics; in a band of well-to-do humans who have elders, long-term survival is probably common enough that the dating scene has a higher impact on reproductive fitness than raw survival skill.
    - kokanator 5y ago
      >in a band of well-to-do humans... Very sincere question. From my understanding, most bands were not well to do and specialization wasn't so common until recent history ( agrarian ages ). So in these instances wouldn't cognitive abilities be more generally valuable? Also, if you were a gathering type and needed to survive for a week away from your group the cognitive skills to recognize resources, weather, threats, etc as well as navigate back to your group would require a certain aptitude. Those without the aptitude would simply not return. Correct?
      - wizzwizz4 5y ago
- wearywanderer 5y ago
  > Oxygen deprivation at high altitudes This is actually three examples in one. Tibetans, Andeans, and Ethiopians each have their own unique version of this adaptation.
  - wizzwizz4 5y ago
    Same with the skin tone one; skin tone tells you (roughly) the latitude where a population was recently, but (as adaptions go) a population's skin tone changes pretty quickly.
sudosysgen 5y ago
Have humans been bred for hundreds of generations for extremely specific tasks? No? Then there is no reason to assume differential cognitive features in humans. Humans have by and large evolved in extremely similar cognitive environments where the most complex cognitive tasks were associated to social functions and as far as we can tell these are extremely similar for 99% of human evolutionary history across all groups.
- KhoomeiK 5y ago
  It's impossible that cross-cultural variations in societal structure or environment imparted a selection bias acting upon certain cognitive traits that would explain the observed disparities we see in modern data?
  - sudosysgen 5y ago
    Which ones? For the vast majority of human history societal structures were incredibly similar. And you can observe any societal structure in any general geographic area, more or less, controlling for very low population densities. So no, I don't see it. Similarly, I don't see what kinds of environmental factors would have a huge impact of cognitive load. For the vast majority of human history they are staggeringly similar and less of a factor than social structure.
    - KhoomeiK 5y ago
      You don't need hundreds of thousands of years to have meaningful shifts in allelic distribution. 10,000 years of agriculture is more than enough to select for height, lactase persistence, and more [1]. I don't think it's a far shot to conjecture a relationship between certain modes of civilization and cognitive features that they select for. I can't point to conclusive empirical evidence for this but my problem is just with people making the study of these issues taboo and denying the scientific possibility. [1] https://www.sciencedaily.com/releases/2015/11/151123202631.htm https://www.sciencedaily.com/releases/2015/11/151123202631.h...
      - 5y ago

wizzwizz4 5y ago

Humans haven't had multiple generations of selective breeding to select for particular cognitive traits. We have, however, had: • Sunburn / vitamin D deficiency • Oxygen deprivation at high altitudes • Free diving which have had obvious effects on certain human populations. But mentally, we're all pretty much just human, same as any other; variation is massive, yes, but it can be pretty big between siblings. Seeing “sheep dog breeds have a herding instinct” doesn't tell you much about humans. When people try to argue a “genetic basis” for a particular trait, they're usually just trying to justify racism.

newfriend 5y ago
Exactly. Different populations of humans vary wildly by almost every physical trait, such as height, build, bone structure, skin, hair type, eye color, muscle fiber. But when it comes to the brain, we are all exactly the same.
- sudosysgen 5y ago
  Muscle fiber variations across humans are pretty small. They're really only very noticeable as far as the extremes, or in quite small populations. Similarly, hair types are barely different. But to tell you a story, the village my ancestors lived in for centuries had people with smooth blond hair and people like me with extremely stiff black hair. Same for eye color. Anyways, I digress, these are generally single-gene variations which is why you will find most of the variation in most populations. Height and build is an interesting one. For most of history heights were very similar across populations. Actually, the only exception we know of were Anglo-Saxon settlers, and some peoples in South-East Asia. This suggests that people even in extremely remote places had incredibly similar evolutionary pressures that led to almost identical heights. But nowadays, the specificities of the impact on a changing diet are different [https://www.tandfonline.com/doi/abs/10.1080/20780389.2012.657489 https://www.tandfonline.com/doi/abs/10.1080/20780389.2012.65...]. Skin is really the biggest one, because Vitamin-D deficiency and skin cancer are huge evolutionary pressures. But as we've seen, otherwise it's pretty clear humans evolved in broadly similar environments and found very similar tradeoffs. This is especially true for intelligence where the biggest load for intelligence was social interactions, and where social structures are very similar.
kokanator 5y ago
I know people don't want to admit to genetic impacts on cognition but there have been pressures over many generations for these traits and those pressures have been different all over the world. Take the example of a genetic lineage living in a jungle where it is necessary to know the difference, availability, dietary qualities, medicinal aspects of thousands of plants. Not to mention predatory dangers, snake dangers, environmental dangers, etc. In this case, the individual with high aptitudes for memorization, categorization and pattern matching would survive at a substantially higher rate than those with lower aptitudes. Remember, a small band does not have the resources to support low producing members so they would not be artificially perpetuated.
- wizzwizz4 5y ago
  No; the individual with high aptitudes for memorisation, categorisation and pattern-matching would become the local healing expert, likely apprenticed to whoever was best at it before. Everyone else would focus primarily on the predatory and environmental dangers, plus their own specialisms (and, you know, everything else). Remember: we live in a society. So did our ancestors. Intelligence is a pretty general skill; all sorts of different selection pressures push it up, not least of all interpersonal politics; in a band of well-to-do humans who have elders, long-term survival is probably common enough that the dating scene has a higher impact on reproductive fitness than raw survival skill.
  - kokanator 5y ago
    >in a band of well-to-do humans... Very sincere question. From my understanding, most bands were not well to do and specialization wasn't so common until recent history ( agrarian ages ). So in these instances wouldn't cognitive abilities be more generally valuable? Also, if you were a gathering type and needed to survive for a week away from your group the cognitive skills to recognize resources, weather, threats, etc as well as navigate back to your group would require a certain aptitude. Those without the aptitude would simply not return. Correct?
    - wizzwizz4 5y ago
wearywanderer 5y ago
> Oxygen deprivation at high altitudes This is actually three examples in one. Tibetans, Andeans, and Ethiopians each have their own unique version of this adaptation.
- wizzwizz4 5y ago
  Same with the skin tone one; skin tone tells you (roughly) the latitude where a population was recently, but (as adaptions go) a population's skin tone changes pretty quickly.

sudosysgen 5y ago

Have humans been bred for hundreds of generations for extremely specific tasks? No? Then there is no reason to assume differential cognitive features in humans. Humans have by and large evolved in extremely similar cognitive environments where the most complex cognitive tasks were associated to social functions and as far as we can tell these are extremely similar for 99% of human evolutionary history across all groups.

KhoomeiK 5y ago
It's impossible that cross-cultural variations in societal structure or environment imparted a selection bias acting upon certain cognitive traits that would explain the observed disparities we see in modern data?
- sudosysgen 5y ago
  Which ones? For the vast majority of human history societal structures were incredibly similar. And you can observe any societal structure in any general geographic area, more or less, controlling for very low population densities. So no, I don't see it. Similarly, I don't see what kinds of environmental factors would have a huge impact of cognitive load. For the vast majority of human history they are staggeringly similar and less of a factor than social structure.
  - KhoomeiK 5y ago
    You don't need hundreds of thousands of years to have meaningful shifts in allelic distribution. 10,000 years of agriculture is more than enough to select for height, lactase persistence, and more [1]. I don't think it's a far shot to conjecture a relationship between certain modes of civilization and cognitive features that they select for. I can't point to conclusive empirical evidence for this but my problem is just with people making the study of these issues taboo and denying the scientific possibility. [1] https://www.sciencedaily.com/releases/2015/11/151123202631.htm https://www.sciencedaily.com/releases/2015/11/151123202631.h...
    - 5y ago