The 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:
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:
I'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.
There are really intelligent people out there who could never pass a calculus class, much less thermodynamics. Do you want them in your program taking up all the time of the teacher, stopping those proficient in math from getting the education they deserve?
It seems people get better at what they practice. I suspect anyone (barring genuine mental disability of some kind) could master calculus and thermodynamics if they were sufficiently motivated.
I'm basing it on both my time as a math tutor for Pima Community College and on people I have known.
People like my mother who, if she can quantify the data she can effectively do algebra, but as soon as X and Y appear she shuts down. She cannot make the jump to the abstract thinking of math, and it curtailed her ability to go back to college. It didn't help that her math teacher in 9th grade told her that she would never be good at math, much like many women from poor backgrounds. (I have no study, only the experience in tutoring on how many women said that a teacher told them not to bother, and could never make it over that hump.) Now you say that it's merely psychological for them and that they could. I'm telling you that for as much work as some of these people I tutored put in, they had a mental block that they simply could not overcome, fighting their way to a C in college algebra so they could get to where they're going.
I can give as an example my boyfriend, who can speak and teach two languages better than most people here can in their native language, and is a promising Ph.D candidate in his program. He worked for a month straight (with my help) to raise his GRE math to a minimum score. His limit may be calculus, but certainly not higher math, and not upper level sciences. Yet I have seen this man wake up, read, write, sleep, and repeat for weeks straight.
He's a gifted writer and academic, but even if he could muddle through (say...) managed information systems, he'd never be more than mediocre because his brain simply does not work that way. (He still asks for help with his Mac.) Square peg, round hole.
It doesn't benefit those who have a passion for the sciences to put him and dozens of others in the same class, wearing down the professor because they struggle to grasp concepts that future scientists understood in fifth grade.
1. I worked for a few years in the remedial math centre for mature students in my university, and one of my best friends did his doctorate in teaching mature students mathematics. Based on my experience, had I taken your attitude then I would have just not shown up for work.
2. I disagree that it doesn't benefit the stronger students. It was awfully hard for me to learn to teach mathematics, because I had never really had to learn it in a step by step way myself. However, when I did learn to teach an area, my understanding was orders of magnitude higher because I had the understanding of somebody gifted in the area but the method and the attention to detail of somebody who has learned it the hard way. If you mix classes with high and low skilled students, you just have to make sure you rely on the high skilled students as a teaching resource.
1. Just because I didn't believe they could do differential equations doesn't mean that I didn't believe they could learn college-leve. algebra with some coaching. I had more faith in them than they did of themselves, in many cases.
2. There have been many studies that have tried what you say. The problem is that the class must go slower to accommodate the slower students. Engineering degrees already have so much packed into them that they often can't take classes of interest -- are we going to make it even longer?
My argument is that we have a surplus of humanities majors and the funding for them is disproportional to our basic need to advance scientific knowledge. Additionally, we must remain competitive with other countries that realize that STEM is the way to economic dominance.
The humanities are subjects that can be explored at home by anyone who has the luxury of free time. While I admit that a hand-holding professor can help you traverse the field quicker and lead you to insight that would be difficult to divine on your own, there are books and audio lectures that can do the same job. And what's stopping anyone from joining a mailing list on the topic of interest?
Even "big" art projects pale in comparison to the funding requirements of basic science research. We need to make sure every lab is fully-stocked with not only minds, but the latest equipment necessary to keep pace with the advancements being made at the top institutions.
The commenter did not say kill the liberal arts, he said to stop funding them. Many of the best thinkers and artists I know are self taught. Liberal arts costs a lot less to learn and teach than most STEN subjects.
Liberal arts should be clearly defined as a leisure activity, one that everyone has a right to, but not something that we should subsidize at the expense of advances in human health.
You can enjoy the liberal arts if you're dead. It's just a matter of priorities.
The fact that it's so much cheaper to teach the liberal arts, yet the same tuition is charged, means that they are already much less subsidized. If you work out tuition paid by students and compare it to department salaries/expenses, humanities departments often turn a net profit for their universities (http://campuscomments.wordpress.com/2010/03/25/ah-bartleby-a...). If you charged students proportionally to the amount it cost to educate them for every credit-hour (i.e. equal subsidies across fields), STEM tuitions would be 20% to 50% higher.
On the other hand, I don't see much reason to subsidize medical education or research across the board, given the huge profits in it; income from patent royalties ought to be sufficient to pay for most of the needed research and education. An exception is harder-to-monetize research, like running clinical trials for old generic medications where it's not profitable for the private sector to do so (since they wouldn't be able to patent the result), or studying diseases that primarily affect poor countries.
Studying engineering isn't the same as innovating, but you accept that people need to know the field first. the same is true for other fields, even if the domain knowledge isn't obvious to you.
Can you point to some great artists and writers who studied art history or literature? I agree that formal study and practice of music (not the same as studying music history btw) has lead to a lot of great music.
What about editing, critiquing, or writing pop novels(perhaps somewhat equivalent to overseeing new devices or just engineering common devices). That also needs to get done.
Unless we're just talking about adding an aspect of fun to research so existing scientists enjoy their work more (or tend to pursue it more eagerly, etc.), a necessary but insufficient condition for gamification is simplicity; and if we can find a way to break complex research down into tasks that are simple enough for almost anyone to complete, why not just underpay people on Mturk to do it and skip having to make it fun?
Not living to (say) 150 is humanity's greatest problem?? And you're serious??
Ever stop to think of world hunger? Malnutrition still is the global leading cause of mortality in the world. And you're arguing to crowdsource a solution to aging which is supposedly "humanity's greatest problem" because us first-worlders can't live to 150, because having their genes fortified (or whatever) most certainly is not going to do much good for those that simply can't get enough nutrients.
This is only a problem to that tiny privileged part of humanity that has no worries whatsoever about the two lowest levels of the Hierarchy of Needs. And you must be well aware which side of the fence you're on, how many there are suffering on the other side, and you have the gall to pose THIS as humanity's greatest problem?
No. I don't easily use a "but the starving kids in Africa have it so much worse" argument, except in this case it's directly relevant.
And don't get me wrong, I'm not against longevity research, cancer research or any kind of medical advances but at least they don't fucking claim they're solving a greater problem than fucking World Hunger.
Aging kills something of the order of 100,000 people every day, about twice as many people as all other causes put together: hunger, violence, accidents, etc.
The majority of those deaths are amongst the poor. Aging also causes great suffering for hundreds of millions of people on a daily basis. The majority of those people are also poor - the poor suffer far more greatly than the wealthy because of degenerative aging due to their comparative lack of access to what palliative treatments do exist.
If not for aging, the poor might have a far better chance of bettering their lot in life - they'd have no imposed time limit on working their way out of poverty, no need for large families to support them in their old age, and so forth.
So your hair shirt view of the world is completely wrong. Aging is the greatest problem, and like all universal problems falls most heavily on the poor.
That's an interesting point about large families...birth rates would probably fall pretty dramatically.
Another potential benefit is that really long-lived people might take a longer-term view on other problems. It'd probably change the global warming debate pretty significantly, for example, if everybody right now had a life expectancy of a thousand.
I can't help solve the world's hunger problems when I'm dead, so in my opinion humanity's greatest problem is death.
Related: in this TED talk[1] Aubrey de Grey makes the assertion that extending life by another 20 years or so is an incredible feat because in that added 20 years science will figure out how to add 20 more, etc.
> 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.
The 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?
To 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.)
Mostly, I'd never stop learning, and I'd apply everything I learned.
Consider the sum total of human knowledge today. Consider how small a fraction of it any one person knows.
Within the next month, I'll have completed a PhD in computer science. It took me years to learn the fundamentals of one field, plus years more to get practical experience by tinkering in numerous areas, plus years more to become an expert in one narrow area (scalable concurrent data structures) and advance the state of the art in that area. Take a look at http://matt.might.net/articles/phd-school-in-pictures/ to get a clearer picture of scale; now consider what a few million or billion lifetimes could produce, between research, practical work, exploration, and just good old-fashioned tinkering.
How many of those narrow areas exist in one field alone? How many more fields exist to explore? How many more will exist by that point? What happens when someone with expert-level knowledge in a pile of those fields starts applying them to each other? And most importantly, do you really think it ever stops?
Apart from that, I'd have plenty of time between learning everything and creating new things to enjoy the enormous amount of available entertainment created over the aeons, in all its various forms.
I think the future sounds awesome, and I want to see all of it. :)
Well, there are books, movies, TV shows, there is art and music and languages... and you haven't even touched on seriously studying different sciences up to a respectable level. I think it would benefit humanity a lot if people could have a much longer lifespan during which they can actually do things.
Think of all the time you could spend learning... also, think of all the time spent learning and experiences and eventually wisdom accumulated in even just one human being by the time they are 60, 70.... only to have it practically all lost forever once you die?
Also, wouldn't you just love to be alive only to see what the future will actually look like? it has been quite some time now since the last real paradigm-shift and real heavy impact innovation that changes our lives forever. I would love to see what is coming.
There 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.
A 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 :)
The 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.
That 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.
Obviously, 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.
Significantly 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.
Evolutionary 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.
Why would evolution need that? If grandpa is badly adapted, he'll starve/get eaten/etc; no need for a built-in kill switch. In fact, if there were a kill switch getting rid of it would be highly adaptive, if only because you could be around to defend your great-grandchildren.
(Of course, we do die. But the explanation looks more like "growing and reproducing quicker beats longevity" than like "planned obsolescence".)
Grandpa wears out, yet competes for resources. Kill him off, more for the healthy youngsters. Certainly its selective, at the family/community level, choosing to keep more-efficient members.
I also think, making grandparents less mobile means they are around the campfire teaching the youngsters. It makes sense it would be selected for in a race of communicators.
The Darwinist reasoning behind rates of aging goes something like this. A adult mouse has a high chance of being killed in a random year (above 20%) a Parrot has a low chance (below 3%). Maintaining a body into old age has a cost that reduces reproductive capability in a given year and a benefit of increasing the number of years of reproductive capability. There are also minimums of capability in the wild where vision and mobility link to survival rates such that there are thresholds below which rates of survival dramatically decrease.
Thus, the number of healthy years in the wild relates to both the probability of an external death AND internal heath issues. For a mouse this suggests a minimum of internal maintenance for maximum reproduction where a parrot can make significant trade-offs in reproduction in order to live 10x as long and have more long term reproductive chances.
However, that's in the natural setting. A pet (mouse, cat, parrot) can live slightly longer in captivity by surviving pat the point where it can find food for it's self. If you look a human vision decline people are significantly less capable of surviving on their own before they lose reproductive capability. And in that "unnatural" old age it's not uncommon for various species to have increasing reproductive issues.
But the degree to which aging is programmed - versus simply an unhappy stochastic decay due to diminishing selection pressures in later life - is a big and ongoing debate. Some species clearly have a lot of programming going on. For example, salmon age at a rate determined by the laziness of bears near to their particular rivers:
But there are equally good counter examples for many more species that suggest the situation is that evolution sets up to win the short race, front-loading as much as it can for early success, and then the selection pressure drops off after you had your shot at reproductive success. All that front-loading produces unpleasant later consequences as things fall apart - you're not set up for the long term.
The adaptive immune system is a good example of this - it's a system that could never run as evolved for an indefinite period of time. It's always going to crash and burn at some point, and that's somewhat a consequence of how it's evolved to run extremely effectively right out of the gate in early life:
This is a group selection argument. Why do you think the group selection pressure outweighs the selection pressure on individuals (which favors organisms who can produce the most offspring, and hence favors organisms who have long reproductive lives)?
Only in social creatures, who routinely share resources at some level. Like families or villages. It doesn't have to outweight anything; its just another pressure at work. So we settle at some mean reproductive interval and some lifespan, that optimizes for all the environmental factors in play.
Imagine you're born into a tribe that has evolved to purposefully die, but you are a mutant that lives twice as long and has twice as many kids. What stops your genes from quickly spreading?
All known species die of old age. This includes species that are not social and do not share resources. Group selection can not be the mechanism at play here.
All known species share their ecological niche with the rest of their members. They are also social to the extent that they court and reproduce.
In your example, what stops the genes from spreading is that the entire village dies of starvation or competition with other tribes that have younger, fitter members.
Its a matter of degree. Humans are social to a high degree, but possibly not as high as ants for instance. Ants eat members of the tribe that are injured, an extreme example of group-efficiency taking priority over the individual.
In a somewhat unrelated idea. I've always wondered what the prospect of immortality, or longer average lifespans means in a world with rapid technological change. I'm borrowing from the idea of future shock.
Young people on average, seem to be more acceptant of new technology, where older seem to be less acceptant. Additionally, from personal experience; I think younger people think about problems differently as well which leads to new developments. It makes me wonder, even if our capabilities to develop new technology are growing (Kurzweil's theory of Accelerating change) perhaps the age of both the general population, and the engineers will cause some level of impedance.
Along the same lines, if a growing population requires growing technological change. And my concept is correct, that age reduces technological evolution, is it possible that it also reduces our ability to adapt, and a natural population balance occurs?
I think it depends on the form immortality takes. Old people are less adapt at technology for two main reasons they have less free time to experiment and it takes longer for them to learn. If immortality means you never retire but the average work week is 3 days and you have the brains of a 22 year old then I don't think there is going to be much of a problem. If everyone is stuck working 40+ hour weeks with a biological age of 70+ then adaptation is going to be an issue.
What if young people's much-lauded adaptablilty is simply, they haven't learned Anything yet so accept the 1st model they come across? That makes them appear adaptable, yet are no more adaptable than older members of society.
I think to change anything substantially, you have to wait for a complete turnover - everybody has to die off, before the seeds of change can take root.
If that would be the only thing going on, you wouldn't be seeing a drastic decline in the ability to memorize new information that isn't tied to complex models of the world, such as sequences of random numbers, in aging people.
Again, cognitive decline in the aged is taking it a step further.
Young people (< 20yrs?) are purportedly more adaptable than older folks, say 20-50. I maintain they aren't really adaptive, they simply have more choices when they learn their first pattern. And they have many patterns to learn, which takes years, perpetuating the myth that they are adaptable.
Teaching a 22 year old PHD student or a 22 year old collage dropout a brand new skill does not favor the dropout. However, there is a fair amount of research that link rates of learning with biological age. With critical time periods that favor specific types of skill acquisition with significant benefits. What's interesting is ~25 years old is one of those cut of periods AND education tends to end at about that age.
PS: There is also trade offs involved which probably provided evolutionary benefits to those cutoff ages.
Perhaps cause and effect are reversed. Measuring young people, many whom are college students shows they stop learning when they leave college - not surprising.
Neuroscience researchers are a little more rigorous than your giving credit for.
When they want to test learning they find people that don't know something, teach it to them, and test them at all points in the process. They also don't limit themselves to a single type of skill and can measure improvement based on how much they improve over time to measure long term skills acquisition.
Hm. "Don't know something" is not a rigourous state at all. Associations are how we know something; older students have more of them.
Unless they limit themselves to reflex action or some such, it becomes impossible to separate previous learning of anything complex.
I think I give researchers plenty of credit. But they don't often have the time/resources to have many/any controls. When a remarkable correlation appears (like 'students stop learning about when they leave school') I call foul.
evolution is not about adaptability of a species, it's about adaptability of individuals (it's not a centralized decision taken for the well-being of a species, but rather a consequence of individuals having more chances to pass their genes than others. The lucky ones are more adaptive).
If you take 2 individuals and one dies sooner than the later, the alive one will have had more chances to pass his genes, so it's not adaptive to have mechanism to ensure our deaths.
I do not think ere is need to postulate a mechanism for death. I think death is a side effect of the evolutionary competition between keeping the current organism healthy and creating new organisms. One would want both, but lack of resources forces a 'choice'.
Apparently, it typically is better to create new organisms every now and then. That may just be energetically better or it may be because (in particular, sexual) reproduction allows for faster adaptation to changed circumstances
Actually 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.
But lifespan and reproductive lifespan are different. Suppose we could live to be 1000, but only reproduce from ages 15 to 65. Then the equilibrium number of years per generation would be right around 40.
I'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.
The 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.
> Longer lifespans cause fewer generations per time period
This is not true though. It would be true assuming a constant population size or a single offspring. The number of children I have and the number of children my children have has nothing to do with how long we live.
But, how long you live might affect how many children you have.
Think of it this way: if you knew you had a high probability of living to 80, you might decide to have fewer offspring so that you could dedicate your earnings to supporting yourself in your later years (children are very expensive after all).
Regardless of whether this hypothesis is true, clearly the number of years you live likely has some bearing on how many children you might choose to have.
I doubt it. If evolution really needed death then why does an immortal jelly-fish (http://en.wikipedia.org/wiki/Turritopsis_nutricula) exist? Granted their final life stage is a polyp which creates a new young medusa, but there theoretically could be a specimen that is 7 millions years old. Either way they wouldn't need to change for number of generations.
The interesting question is how you figure out those curves in a decent amount of time and cost. When you pull a lobster out of a wild population, how do you determine how old it is? Lobsters live way too long to take the sit and wait approach with a lab population, and to date there's no reliable way to determine lobster age. So that's still a real challenge, not least because there isn't all that much interest in lobster aging.
One 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
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.
When 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.
Silly 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?
Sort 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.
This is just a model - a map of reality which may give some helpful predictions and insight about the territory, but is not the same thing as the territory (reality) itself. See, for instance, http://wiki.lesswrong.com/wiki/The_map_is_not_the_territory
Well, sure. Except the equation gives a 2 in 7 billion chance of even making it to 114 (note that in reality your odds are empirically better). The odds of reaching 136 are 1 in 10^86. For comparison, there are only 10^80 atoms in the universe...
Fun 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.
http://www.fightaging.org/archives/2010/05/applying-reliabil...
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-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