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    279 points petethomas | 37 comments | | HN request time: 0.001s | source | bottom
    1. pinkmuffinere ◴[] No.45298755[source]
    It’s tempting to see things like this and think “well of course it does, because that’s how we evolved”. But I think that might just be post-rationalization? At the very least, I think the argument _doesn’t_ hold for periodic famine, extreme temperatures, most disease, etc even though we also evolved with those things. Is there any guiding principle that separates the things-we-evolved-with-that-are-good vs the -that-are-bad? Or is it really just a case-by-case examination?
    replies(5): >>45298762 #>>45299023 #>>45299467 #>>45299663 #>>45304373 #
    2. Jweb_Guru ◴[] No.45298762[source]
    Entirely case by case. It's further confounded by the fact that a bunch of things that are bad for us don't exert strong selective pressure in the first place.
    replies(1): >>45301708 #
    3. usef- ◴[] No.45299023[source]
    The things you mention are sudden extremes: famine (extreme hunger), extreme temperature, being hit by a disease. The highest skin cancer group seems to be those that get sporadic extremes of sun (eg. the indoor office worker that burns on the weekend). That kind of rapid change in sunshine quantity was tough to ever do naturally. Even if you could hide from the sun in (rare) caves in the middle of summer it would be for hours not weeks. It wasn't something done normally in life.

    I do think we also have observation on our side here, as it has been seen for a long time that people with outdoor occupations have lower skin cancer rates than indoor (eg "Occupational sunlight exposure and melanoma in the U.S. Navy", 1990). Why those stories never broke through to the mainstream is an interesting question.

    (I know they're out of fashion now, but the paleo community was talking about doing ~10 minutes of direct sun a day almost two decades ago, with strict guidance to avoid burning, roughly based on the above reasons)

    replies(1): >>45304543 #
    4. globular-toast ◴[] No.45299467[source]
    Yeah, I've always found it a very weird and weak argument. There are plenty of things we've evolved with that would be considered pretty bad for us now. For example, we evolved as a polygamous species (like virtually all mammals), meaning harams, lots of sexless males and fighting etc.

    Also important to remember evolution operates at a population level, not individual. We are descended from females that were able to survive at least pregnancy and carry the second to term, but it doesn't matter if they die in the second pregnancy. We're descended from males that were able to mate with said females, but they could have died very shortly after mating. So if you follow "what we evolved with" then that's all you're likely to get.

    replies(1): >>45304949 #
    5. qalmakka ◴[] No.45299663[source]
    Exactly - as if evolution cared enough about keeping us healthy after childbearing age. It's hard to state "yeah we've evolved to live like that, of course it's good for us" because clearly keeping us alive after the age of 40 really wasn't _that_ necessary for human survival. There's a lot of perfectly natural stuff that hurts us, including sunlight. Most cancers will only occur in the latter half of our lives, where usually a human historically had already had several children that are now old enough to survive on their own.
    replies(2): >>45307719 #>>45308617 #
    6. annsjdhs ◴[] No.45301708[source]
    > don't exert strong selective pressure in the first place

    This assumes we understand how these things work in the first place. It’s very likely our understanding of evolution is incomplete.

    I make this mistake a lot:

    1. See thing that’s been done a long time a certain way

    2. Modern recommendation is don’t do thing

    3. Revised modern recommendation says “actually wait, do thing”

    4. Revised modern recommendation is now ok because our incomplete model has been updated, whereas it should have always been ok because it’s been that way for a long time

    Put another way: we should give more weight to a repeated pattern observed over thousands of years and heavily question any science that goes against it. Both sides are just estimations, but nowadays it’s almost assumed “old ways bad”. Way too many cases that end up being “way humans have operated for millennia is actually ok”.

    7. brightball ◴[] No.45304373[source]
    Since I was a little kid I was always skeptical of slathering something all over my body just to go outside. Just thought…how did people survive before this stuff if we really need it so bad.
    replies(12): >>45304403 #>>45304421 #>>45304484 #>>45304495 #>>45304592 #>>45304894 #>>45305979 #>>45306448 #>>45306482 #>>45308405 #>>45309932 #>>45311267 #
    8. adrianN ◴[] No.45304403[source]
    If you ask „how did people survive“ the answer is more often than not: „with great difficulty“. Take for example simple hygiene measures like using soap or brushing your teeth or disinfecting wounds.
    replies(2): >>45304548 #>>45304773 #
    9. TinkersW ◴[] No.45304421[source]
    Often living in a different climate zone, US is well south of Europe.
    replies(1): >>45304624 #
    10. throwaway74628 ◴[] No.45304484[source]
    Slathering oneself in mud if you need to endure harsh sun exposure is the most common answer I’ve seen to this question. Otherwise, I agree with your comment, the “best practice” of avoiding sun exposure is as unintuitive as the grain-heavy food pyramid.
    replies(1): >>45307274 #
    11. AppleBananaPie ◴[] No.45304495[source]
    They survived but for a much shorter time?
    12. jerlam ◴[] No.45304543[source]
    > Why those stories never broke through to the mainstream is an interesting question.

    The mainstream media in the US has never been great at communicating any story with nuance or depth. In the 80s and 90s, foods that we've eaten forever were being demonized, like eggs. In 2020, people were being told they shouldn't go outside lest they come within 100 feet of another person.

    To their credit, the general population has never had a shorter attention span and so easily hoodwinked into believing misleading claims.

    Australia's sun recommendations for people of differing skin types is not bad: https://www.sbs.com.au/news/article/tailored-protection-aust...

    13. datadrivenangel ◴[] No.45304548{3}[source]
    Teeth brushing is not as important if you're not eating modern food. Processed sugars really are terrible (but delicious)
    replies(1): >>45309759 #
    14. pitpatagain ◴[] No.45304592[source]
    People didn't used to expose themselves to as much direct sun and covered themselves with a lot more clothes. Traditional clothing in arid sunny areas typically covers everything, look at people in the middle east today.

    I live in a very sunny desert area and it's kind of funny when people assume people from here would be "more tanned". We stay in the shade, the sun will kill you! Anyone working outside is wearing wide brimmed hats and typically has all of their skin covered with clothing even in the heat, people typically have their faces covered with cloth as well.

    Spending time outside with minimal clothing in direct midday sun is a modern weird behavior.

    replies(3): >>45304952 #>>45306393 #>>45307879 #
    15. lstodd ◴[] No.45304624{3}[source]
    56th latitude person can be literally baked by northern mediterannean (~42 lat) March sun in a couple of days. But a couple months later.. no problems climbing mountains all day. We are very adaptable.
    replies(1): >>45304917 #
    16. laserlight ◴[] No.45304773{3}[source]
    Or, the answer is simply “they didn't survive”, which is the case for countless babies who died because an activity as simple as hand-washing wasn't known to be a matter of life and death.
    17. seemaze ◴[] No.45304894[source]
    Global migration outpaced evolutionary adaption a long time ago. Many peoples have adapted to local UV conditions, but can now jump on an airplane and are instantly in a completely different environment.

    Additionally, if you've ever seen a portrait of a human in the UV spectrum, you'll notice how shiny they look. I'm sure modern people have much less protective oils in their skin as a result of increased bathing required by societal and sanitation norms of modern urbanized habitation.

    18. TinkersW ◴[] No.45304917{4}[source]
    You can choose to bake, and your skin will harden up and deal with it, but it will also cause long term leathery skin, which many find unattractive, and increased skin cancer risk.

    Tho I agree with economist article, sun exposure is very good for you, just not high UV exposure.

    replies(1): >>45308258 #
    19. amanaplanacanal ◴[] No.45304949[source]
    Where do you get the idea that we evolved as a polygamous species? The few remaining hunter-gatherer societies don't work like that. I think that kind of polygamy came with agriculture.
    replies(1): >>45305184 #
    20. seemaze ◴[] No.45304952{3}[source]
    Absolutely agree.

    I'm find myself aghast when I travel to different environments and observe people laying in direct sun almost naked. Not that I think they shouldn't, it's just such a stark contrast to my norm. I'll end up with a painful sunburn if I venture outside uncovered for more than 10 minutes at home.

    21. globular-toast ◴[] No.45305184{3}[source]
    The existence of porn should be enough to show that we aren't monogamous. That and the fact that virtually no other mammal is including all the great apes. Monogamy is a thing in birds and they are literally dinosaurs.
    replies(1): >>45305354 #
    22. amanaplanacanal ◴[] No.45305354{4}[source]
    I think possibly we are using different definitions of polygamy. If you mean one male monopolizes the females, I disagree. If you mean that individuals (both male and female) don't mate with just one person, then I agree.
    23. danielmarkbruce ◴[] No.45305979[source]
    Many didn't. On top of that, evolution optimizes for reproduction, not long life. With few exceptions, cancer is a disease of the post child rearing aged folks.
    24. whatevertrevor ◴[] No.45306393{3}[source]
    Yup, I grew up in a hot subtropical climate and the best counter to the summer was to stay indoors, hydrate. If you have to be outdoors, stay in the shade, if you have to be exposed to the sun, cover yourself. All of the benefits you get from being in direct sunlight can be gained with just being outdoors in shaded areas, maybe for a slightly longer time.

    The way western culture glorifies direct exposure to the sun is always hilarious to me, everyone lining up to burn their skin for hours on end to "catch up" on sunlight exposure. Instead of just playing an outdoor sport under some trees or being outdoors in the morning/evening when sunlight is a lot less potent and weather is a lot more pleasant.

    25. Earw0rm ◴[] No.45306448[source]
    White people - depending on your definition, I mean pale-skinned Northern Europeans - are adapted to live north of about 45 degrees.

    Obviously they live lots of other places now, but evolution is slow to catch up.

    If you drive through France for a day, you can literally see the change from north to south, "could be Dutch" in the far north to "could be Spanish" in the south. Of course lots of people move around but I'm talking about averages.

    26. anthomtb ◴[] No.45306482[source]
    > skeptical of slathering something all over my body just to go outside

    Missing nuance: Outside for how long? And how strong is the sun?

    Even with my pasty Northern European complexion, I'm skipping the sunscreen for a 20 minute walk to lunch in November. But for a 10 hour hike above treeline in July? I'll be re-applying every two hours.

    27. jerlam ◴[] No.45307274{3}[source]
    That food pyramid hasn't been recommended in 20 years.
    replies(1): >>45307500 #
    28. throwaway74628 ◴[] No.45307500{4}[source]
    That’s my point.
    29. papyrus9244 ◴[] No.45307719[source]
    > because clearly keeping us alive after the age of 40 really wasn't _that_ necessary for human survival.

    That's a very common misconception. Being alive after 40 is quite necessary if you are a member of a gregarious species that (bar exceptions) always lives in community. And it's not only about the survival of your own genes, it's about the survival of the genes of the whole community.

    30. xenospn ◴[] No.45307879{3}[source]
    People in greece/israel/italy/etc don't cover themselves much and they have very long lives.
    31. lstodd ◴[] No.45308258{5}[source]
    I'd say more like comments here: it's not high UV, it's high delta between actual UV flux and what one's skin was expecting. So pace it, like you would do when first starting lifting weights. The final tolerance is suprisingly high.
    replies(1): >>45310523 #
    32. aidenn0 ◴[] No.45308405[source]
    I live at a much lower latitude (about the same as Morocco) than my Celtic ancestors did.
    33. DoctorOetker ◴[] No.45308617[source]
    Selection pressure does not simply select on "did or did not reproduce" it selects on reproduction rate (compare 2 individuals, both having parented a first child, but one dies afterwards while the other continues to occasionally reproduce before dying. The latter displays higher fitness.

    Its like any poisson process, a recent event does not inherently lower the probability density for the next event.

    Achieving the minimum necessary for reproduction is not representative of the distribution of reproductive success scores.

    34. adrianN ◴[] No.45309759{4}[source]
    If by modern you mean anything since agriculture was invented, then perhaps.
    35. astura ◴[] No.45309932[source]
    Long sleeves and wide brim hats.
    36. bschwarz ◴[] No.45310523{6}[source]
    SPF 4: https://www.health.harvard.edu/skin-and-hair/are-there-benef...
    37. heavyset_go ◴[] No.45311267[source]
    The ozone layer wasn't as weak as it is now. We receive more radiation from the sun at the surface than we did before CFCs.

    In the past, people, in general, remained in the general vicinity of where they were born. Different skin types adapted to different amounts of sunlight.

    We also didn't have the knowledge to link death and disease with their actual causes.

    That said, in the past, people used variety of materials for sunscreen without the knowledge that "too much radiation bad". Mud/clay/etc seems to be something multiple cultures over time used. In cultures where working in the sun is common, wearing long clothes that blocks the sun is also a thing, and works like sunscreen.

    Given that last point, I think baking in the sun while nearly naked to the point of developing disease is a relatively recent cultural thing, but that's just a guess.