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Comment by fastball | Hacker News Reader

Confirmation bias is a creepy thing sometimes.

I was literally asking my Google Home last night what the longest living vertebrate was and it told me the Greenland shark.

Had a whole conversation about it over dinner, arguing about how accurate we think these age-establishing methods are.

Though the more interesting part of our conversation (I would say) was wondering how ages work out in practice. For example why do the vast majority of animals not live beyond 20 years, even when we try to keep them alive as long as possible (dogs)? If the environment was different would longevity be different for all species, e.g more oxygen in the atmosphere or a longer day-night cycle? Etc.

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By far the most important reason dictating lifespan is evolvability - the ability to adapt genetically [0].

This has so great effect that it's easy to observe even in a simple computer simulations. If you don't adapt and the environment is changing, then you go extinct.

Think about this sharks and how much their environment has changed since they were born. As a spices they will have a very hard time adapting to the changes we induce in the environment. While small animals that have lifespan in weeks, months or few years will be adapting a lot faster. E.g. in one generation of this shark a mouse will go trough up to 900 generations with up to 12 offspring in each generation.

This shark probably will go extinct and mice will thrive.

Interesting consequence of this effect is that our lifespan is most likely not dictated by any fundamental limitations of biological machinery to maintain us healthy indefinitely.

A lot more likely is that we are evolutionary designed to get old and die.

https://en.wikipedia.org/wiki/Evolvability

Thanks you, nice link. The opposite side of this is biological immortality. This wiki has a good discussion.

https://en.m.wikipedia.org/wiki/Biological_immortality

I’m not educated on this topic at all, but wouldn’t birth rate be more relevant than aging? If this shark lives 400 years but has kids often, it could also go through 900 generations like the mice. Presumably if the environment isn’t favorable then the old members of the species would die off anyway.

The older living sharks would use up resources that the younger ones need to thrive. So it’s way more efficient to get the older population out of the way sooner.

The longevity of the Greenland shark, humans and other long living animals, is in spite of evolutionary pressure to reproduce, raise the next generation and die.

Consider that a litter of sharks born in year 100 would be very closely related to a litter sharks born in year 400. Imagine the same pair of sharks mate over that span of time, those siblings are even closer. To me, evolution is a very deep graph of descendants. The scenario you propose is a very wide and shallow graph.

N.B.: I'm a layman on this topic as well.

To counter this a little, there is a jelly fish Turritopsis Dohrnii which is biological immortal. Those jelly fish and sponges (which can get very old too) are very, very old/successful species.

Heartrate has been found to play a big part.

https://pubmed.ncbi.nlm.nih.gov/9316546/

Animals with slower heart rates tend to be longer lived. An interesting sidenote are bats, which have heart rates about the same as similarly sized small mammals like mice, but due to their nightly torpor state where their heart rate is significantly lowered, they tend to live 20-25 years opposed to the 3-4 mice usually live.

Hmm, less stress, lower heart rate, longer life.

Assuming this is true, I recommend everyone start running!

If I am regularly running, my resting heart rate at night drops into the upper 30s. During the day sitting down, 45-50.

If I haven't been running (for a week or longer) it picks back up in to the mid 40s at night, and around 60 for normal sitting.

Welp... guess I'll die young.

My heart rate when sleeping is 65bpm, and I can't focus on anuthing if my heart rate is below 90bpm during the day.

For what it's worth - I'm a firm believer that what is always healthy for your body, is not always healthy for your mind.

Some of the most productive people I know eat nothing but donuts and coffee, and don't exercise at all. They're smart, driven, and highly successful.

Meanwhile, I know a lot of people who put exercise and food as a priority, and don't seem nearly as sharp or as successful. Maybe this all washes out, with age.

Point is - do whatever works for you. Don't let some blog, or some person on the internet, tell you how to perform optimally!

I did see a cardiologist after COVID-19, he did prescribe some medicine to "calm my heart down a bit", I don't meet actual criteria for tachycardia and he agree in the end that I can postpone medicine if I start any aerobic exercise -- which I still didn't, except for VR games, which can be really intense, but alas, I don't have the time for or discipline.

You heart might survive, but your joints probably won't. The stress you put on them when running/sporting when young will come back to haunt you later on!

Don't ask me how I know :-)

Guess I’ll go for a swim!

This is not true, take your time and run in moderation and you'll have no increased risk of joint pain when you get older.

(Assuming you're not joking) You don't seem to be counting all the extra times your heart beats when you're actually running.

Birds are metabolically much more active than mammals yet many have long lifespans. This prompted another finding that the number of cortical neurons can explain a large part of the variation in lifespan across species.

https://www.labroots.com/trending/cell-and-molecular-biology...

Flight gives birds greater protection from predation, which makes evolution towards biologies that pay a higher metabolic cost for greater longevity more advantageous. The same thing applies to larger animals, like cows, which tend to have longer lifespans once you normalize for heart/metabolic rate.

I have read a few studies saying that periodic fasting / starvation can play a role as well.

> For example why do the vast majority of animals not live beyond 20 years, even when we try to keep them alive as long as possible (dogs)? If the environment was different would longevity be different for all species, e.g more oxygen in the atmosphere or a longer day-night cycle? Etc.

A lot of animals just don't need to live longer than 1, 2, or 20 years to reproduce. There is no evolutionary pressure to do so. From our human perceptive life is valuable on its own merit, but nature doesn't see it that way. All it really cares about is replicating those precious DNA molecules, and different species have different strategies for that. For some species, it takes a long time to produce offspring. Whales, for example, live a long time as well. They're huge and it takes a long time for them to become fully grown, find mates, produce offspring, etc. There is a lot of evolutionary pressure to live long. Humans live comparatively long because it takes a long time for individuals to acquire the skills we use as a survival strategy.

Not too much is known about the lives of Greenland sharks, but there are probably some evolutionary pressures for them to live long lives.

>Humans live comparatively long because it takes a long time for individuals to acquire the skills we use as a survival strategy

Species need to live until reproduce, maybe several times, and see the next generation into being able to live on their own. That is about 35-50 for humans (granted the 15-20/generation - relatively prolonged maturation period given our size - is primarily because of the brain/skills development you mentioned). Additionally, because of the complexity of societal organization, skills and other knowledge, we've got boost from having the grand generation around to help and transfer knowledge and experience. That brought us to 60-70.

> confirmation bias ..

Wouldn't that be more an example of the Baader Meinhof effect?

How do people develop their repertoire/knowledge of these “effects” and laws?

Hacker News, sometimes reddit.... IDK of this effect has a name... the graham law maybe?

baader-meinhoff has been a neologism for a long time now, enough so that it isn't really a neoligism anymore, and we just collectively moved onto accepting it as the name of this phenomenon.

there's a lot of these sorts of in-sphere jargon; you'll start picking them up if you peruse the more esoteric threads on tech news blog aggregator sites like this.

like, if one of the original repliers in a thread is "why is this on HN", there's an increased chance imho that you'll run into this sort of techno-cultural salon effect.

Let me share with you one of my favourite pages on Wikipedia: https://en.m.wikipedia.org/wiki/List_of_cognitive_biases

Not OP, but I pretty much only know two effects: Baader–Meinhof effect and Streisand effect. So I guess the answer for knowing this particular one is just that it is famous.

So I guess the answer is that this repertoire grows whenever someone tries to suppress its knowledge.

Once a colleague mentioned it and since then I notice it everywhere :-)

Perhaps it is an example of Cunningham's Law?

Plot twist, OP was referring to personified Google Home having a confirmation bias due to meme-science article proliferation?

Proof of the horrors of lockdown. People now have hour long discussions with google over dinner.

Lifespan is correlated with the time it takes to reproduce. If a species needs a lot of time to reproduce, then only the individuals who live longer will procreate, passing down the genes of long life. On the other hand, if it is too quick to reproduce, genes for short lifespan will abound, pressuring the shorter lifespans across the population.

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