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Your body wasn’t built to last: a lesson from human mortality rates
- drumdance 15y agoMy dad used to joke that if he made it to 80 he was going to take up smoking again. Alas, he only made it to 79.
- linuxminter 15y agoMy uncle used to joke that if he made it to 60, he'd let me pummel his ass. Alas, I couldn't wait that long and demolished him at the tender age of 55. RIP!
- libraryatnight 15y agoA friend used to say that most things he was warned about started with "Men over the age of 35..." and so once he hit 35 he would stop smoking, drinking, eating horribly etc. We would usually discuss such things on a smokey patio with beers. He's just shy of 35 now, so we'll see ;) Sounds like your dad had a good sense of humor :)
- hezekiah 15y agoWhat the article only touches on, but is even more interesting, is the fact that it's really just a specific case of the general Poisson distribution, a general mathematical result of exponential arrival times of events, of which mortality is but one example: http://en.wikipedia.org/wiki/Poisson_distribution http://en.wikipedia.org/wiki/Poisson_distribution Examples: The number of soldiers killed by horse-kicks each year in each corps in the Prussian cavalry. This example was made famous by a book of Ladislaus Josephovich Bortkiewicz (1868–1931). The number of yeast cells used when brewing Guinness beer. This example was made famous by William Sealy Gosset (1876–1937).[7] The number of phone calls arriving at a call centre per minute. The number of goals in sports involving two competing teams. The number of deaths per year in a given age group. The number of jumps in a stock price in a given time interval. Under an assumption of homogeneity, the number of times a web server is accessed per minute. The number of mutations in a given stretch of DNA after a certain amount of radiation. The proportion of cells that will be infected at a given multiplicity of infection.
- panic 15y agoYou can find the original, less ad-encrusted version of this article at http://gravityandlevity.wordpress.com/2009/07/08/your-body-wasnt-built-to-last-a-lesson-from-human-mortality-rates/ http://gravityandlevity.wordpress.com/2009/07/08/your-body-w....
- fragsworth 15y agoEvolutionary theory would also suggest that we have some mechanism to ensure our deaths. Longer lifespans cause fewer generations per time period, resulting in less adaptability as a species.
- VMG 15y agoLonger lifespans cause fewer generations per time period Only if you assume the non-reproductive members are a net negative (grandparents becoming a burden)
- deleted 15y ago[deleted]
- fragsworth 15y agoActually no, it's a little more complex than that: Regardless of reproductive lifespan, in a population that is in equilibrium (not increasing or decreasing significantly), the average number of (surviving and reproducing) children per individual is going to be 2. So supposing we could live to be 1000 years old, and still reproduce at that age, we'd have an average of 2 generations per 1000 years.
- mrbgty 15y agoI'm curious. What backs up the idea that the average number of children per individual will be 2 regardless of reproductive lifespan? It seems that I've seen a somewhat(?) common pattern among people who have young families and get divorced that often times have another family (+2 children) when they re-marry.
- jowiar 15y agoThe definition of equilibrium. Every child has 2 parents. Thus in each reproduction, every parent creates on average half a child (sounds rather morbid). Thus for the population to remain in equilibrium, each person needs to reproduce, on average, twice.
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- reasonattlm 15y agoThe body can be considered as a system of many redundant components, with aging as the result of progressive unrepaired damage to those components. This is a model that works very well. For further reading, you might look at the application of reliability theory to aging: http://www.fightaging.org/archives/2010/05/applying-reliability-theory-to-aging.php http://www.fightaging.org/archives/2010/05/applying-reliabil... http://en.wikipedia.org/wiki/Reliability_theory_of_aging_and_longevity http://en.wikipedia.org/wiki/Reliability_theory_of_aging_and... Once you start to think along the lines of damage and repair, you inevitably end up in the SENS camp. It's the logical place to be. http://www.fightaging.org/archives/2006/11/the-engineers-viewpoint-treat-change-as-damage.php http://www.fightaging.org/archives/2006/11/the-engineers-vie... Bodies are complex systems and all complex systems can be prolonged in their period of prime operation by sufficiently diligent incremental repair. Developing a toolkit to do that for humans is the point of SENS the research program, with the point of SENS the advocacy program being to help people understand that the scientific community well understands in detail what needs repairing. For more on the biochemistry of damage-that-causes-aging, explained for laypeople, you might look here: http://www.sens.org/sens-research/research-themes http://www.sens.org/sens-research/research-themes
- hallman76 15y agoWe need to "gamify" this research. Farmville carrot-growers could be solving humanity's greatest problem! (I'm totally serious)
- quizbiz 15y agoSo whats the first step? An open source engine on github?
- itmag 15y agohttp://cosmiclog.msnbc.msn.com/_news/2011/11/07/8684955-gamers-create-scientific-recipes http://cosmiclog.msnbc.msn.com/_news/2011/11/07/8684955-game...
- possibilistic 15y agoI'm a computational biochemistry student, and I don't think this is possible. We can gamify protein folding because this is a well-understood, well-characterized problem. What we don't have the slightest clue about is how to restore original cell state, eg. rid cells of aggregate intracellular waste, repair non-trivial DNA damage, restore the extracellular metabolome, etc. I think we should stop funding/granting scholarships to liberal arts majors. Let them become STEM majors.
- jessriedel 15y agoThe chance-of-death plots should be logarithmic, so we can tell if this exponential is really a good fit. On linear plots, it's hard to distinguish exponential decays from 1/x^n decays.
- kingkawn 15y agoThat graph showing survival probability as near 1 for age 0 can't be correct, since mortality is significantly higher in birth and immediately after, then drops for a long time, then shoots up again in old age. This is at least true in westernized countries that have medical care available.
- ArchD 15y agoObviously, this is a simplification. Infants die for other reasons that you can think of to be different from the reasons for which old people die (e.g. cancer), and these reasons are being factored out of the graph.
- ryusage 15y agoI thought the point of the graph was that it didn't matter how or why the people died though? Isn't that part of why it's so surprising?
- yelsgib 15y agoThe point of the graph is that it doesn't matter how or why people die, after a certain age. This is clear from context, though not explicitly stated.
- ajkessler 15y agoSignificantly higher relative to life expectancy of someone who makes it to 10 years old, but still incredibly low in the Western world. It's likely close enough to 0 that it just isn't visible on the graph.
- benjoffe 15y agoThere's also a rise in late adolescence when risk taking and suicide are much higher.
- scotty79 15y agoAre there any other scenarios that lead to Gompertz Law like distribution?
- angdis 15y agoThe longevity of the body is one thing, it is debatable whether or not it can be extended by a lot or a little (or at perhaps until the MTBF of a freak accident). What I rarely see discussion of, however, are philosophical and psychological implications of "living indefinitely". Even if the body is says relatively youthful, what about diseases of the mind? In other words, I am saying that in the same way that increasing life-span has uncovered a plethora of diseases that were previously unknown like cancer, is it possible that further increasing life span may uncover conditions (perhaps purely psychological) that we can't even imagine. Will people _want_ to live 100's of years?
- Tossrock 15y agoThere is an interesting discussion of this in the Mars Trilogy by Kim Stanley Robinson. As people age well past a hundred, they can no longer remember most of their lives, and their cognitive function becomes progressively worse.
- onemoreact 15y agoThere is less separation between mind and body than you are assuming. Old age disease of the mind ARE the direct result of breakdowns in the body.
- andrewflnr 15y agoThen those will become our new research problems, and we will dream of the distant future when we overcome them and can live even longer.
- JoshTriplett 15y agoTo the extent we find bugs that cause the brain to stop working properly over time, we'll need to find and fix those. That falls under "problems we'd love to have". As for the question of whether people want to live for hundreds of years: if you don't want to live longer, you can easily stop. A surprisingly large number of people seem to rationalize the lack of immortality by claiming people won't want to live forever, which strikes me as sour grapes. Given an actual solution that allows people to live forever, the question becomes "do you want to die?", and I seriously doubt many people will say "yes". (Also, if you think of immortality as "hundreds of years", I think you need to recalibrate your scale. I'd like a lifetime measured on a cosmological time scale, and I have no problem conceiving of ways to spend that time.)
- willchang 15y ago> Anyone who paid attention during introductory statistics will recognize that your probability of survival to age t would follow a Poisson distribution, which means exponential decay (and not super-exponential decay). Small correction: survival to time t under the lightning bolt scenario follows an exponential distribution. A Poisson distribution, besides for being discrete, has factorial decay, not exponential decay.
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- j_baker 15y agoSilly question: If I'm understanding this correctly, doesn't this essentially mean that statistically it's possible to live forever? Or is there a point when you statistically have 100% probability of dying?
- jbri 15y agoSort of, depending on the model. For most models, if you take your "probability of dying in year X", and sum that over all the years from 0 to infinity, you'll get a 100% probability of dying at some point. The interesting thing is that there's no individual year with a 100% probability of dying - the certainty of death is just because "forever" is a really long time. There are hypothetical distributions, though, where the sum total of probabilities is less than 100% - where some proportion of the population will, statistically, never die. Of course this brings us to the real issue, which is that what the model says doesn't really matter - if the model disagrees with reality in extreme cases, reality wins.
- usaar333 15y agoOn high ends it definitely is. It predicts no one could have ever lived past 116, but clearly some have: http://en.wikipedia.org/wiki/Oldest_people http://en.wikipedia.org/wiki/Oldest_people
- tikhonj 15y agoIn practice, a sufficiently low probability is indistinguishable from 0.
- Sharlin 15y agoYeah: http://lesswrong.com/lw/mp/0_and_1_are_not_probabilities/ http://lesswrong.com/lw/mp/0_and_1_are_not_probabilities/
- Jimmie 15y agoThink of it like entropy. Statistically a broken egg could place itself back together but that's never going to happen.
- ggwicz 15y agoOne of the sharpest changes (I guess a "point of inflection" it looks like?) seems to be at about 65, or the most common retirement age (here in the states at least). I wonder if there's a connection? In hunter-gatherer societies, elders older than 60 have been observed as 1) looking healthy and 2) still being able to hunt, fish, trap, build, and pretty much everything else along with their younger counterparts. Perhaps at a slower pace, but they're generally far more fit than the modern world's old. Pampered bodies grow sluggish through sloth, movement and their own weight exhausts them. - Seneca
- ams6110 15y agoWhen the conventional retirement age of 65 was established, few people made it much past 70. Social Security is in double trouble now because not only are we facing the retirement of the baby boomers, but they are living a lot longer too.
- kiba 15y agoIn hunter-gatherer societies, elders older than 60 have been observed as 1) looking healthy and 2) still being able to hunt, fish, trap, build, and pretty much everything else along with their younger counterparts. Perhaps at a slower pace, but they're generally far more fit than the modern world's old. Survivorship bias.
- ifearthenight 15y agoFun and interesting read. Personally though I think by only examining mortality rates then half the story has been missed. ie. life expectancy. While intuitively we can see that the probability of dying in any given year increases with the more years you live, perhaps slightly more counter intuitively the longer you live then the longer your life expectancy is (rolling average obviously). Would love to see the two put together somehow and charted.