The Peculiar Mind Trap

A new paper has come out in support of the Grandmother Hypothesis. Briefly, the Grandmother Hypothesis argues that the evolutionary reason human women live so much past child-bearing age is so they can help look after their grandchildren. This study, Grandma plays favourites: X-chromosome relatedness and sex-specific childhood mortality, looked at difference between maternal and paternal grandmothers and the gender of their grandchildren. I came across this study in Newsweek, and here is the most significant paragraph:

"In six of the seven societies, having a paternal grandmother nearby improved the survival of granddaughters (50 percent X-relatedness) by up to 4.5-fold, but for some unknown reason decreased the survival of grandsons (zero percent) by 8 to 29 percent. And a boy had a greater chance of survival if he lived with his maternal grandmother (25 percent X-relatedness) than with his paternal grandmother (zero percent). In four of the seven societies, a girl had a better chance of survival if she lived with her paternal grandmother (50 percent) than her maternal grandmother (25 percent)."

The suggestion here is that kin selection is so finely tuned it can distinguish subtle differences in the genetic relatedness of second-generation offspring. The X chromosome holds about eight percent of our genes. This is from the paper, quoted in Anthropology.net:

"If approximately 92 per cent of our genes are autosomes, then a grandmother shares one-quarter of that, or approximately 23 per cent of her total genes with a grandchild, plus X-relatedness.1 If a grandmother shares no X-chromosome with a grandchild, then their overall genetic relatedness is approximately 23 per cent, and if they share an entire X-chromosome, then it would be approximately 31 per cent. Therefore, MGMs and grandchildren are likely to share 25 per cent of their genomes, while PGM and granddaughter may share a total of approximately 31 per cent of their genes, with a likelihood of 27 per cent inheritance, while a PGM and grandson may share only approximately 23 per cent."

I can't make any comments on the validity of the experiment (I can't get to the actual paper, and even if I could I suspect I'd need to be better versed in statistics) but I've already raised an issue that no-one has been able to resolve for me. I do see some other problems with this. First of all is the mechanism, which hasn't been found beyond a reasonable certainty that the grandmothers are not conciously choosing some grandchildren over others.

There's a suggestion that the grandchildren are giving off a signal of their genetic relatedness such as physical resemblance or smell, but if that were the case wouldn't the grandmothers be able to determine which offspring had their X chromosome and discriminate accordingly? So, for example, paternal grandmothers would know which granddaughters had their X chromosome and help them but not the others, so that would cancel out (I recognise the statistics might already reflect that). This could be tested by collecting the same sort of data but combining that with genetic testing, so that the researchers (but obviously not the people involved) knew exactly who had what X chromosome. They could then test if the maternal grandmothers differentiated between granddaughters based on X-relatedness. Although, this experiment would be hard to pull off because it would take a few decades, they'd need the genetic data of everyone involved (even the deceased) and letting the participants know the nature of the experiment could change the outcome.

The second issue is that paternal grandmothers have a strong negative affect on the survival of grandsons. Now, he may not have her X chromosome, but he does have 23 percent of her other genes so it makes sense for her to help him anyway, but the evidence suggests she hinders him. This appears to be counter-evolutionary.

My final question concerns the reason this study was done in the first place. The question it's trying to answer is this: Why are women able to live for many years after they are able to conceive offspring, a phenomenon seemingly at odds with the idea that members of a species tend to die off once their reproductive days are over? Of course, it's well recognised that for the majority of the time humans have been on the Earth their life span has been a lot shorter than it is now; forty was considered old, fifty would have been exceptional. Historically, women didn't live past their child-bearing years, and few would have seen menopause. Menopause may have come a few years earlier, but probably not substantially earlier. My argument would be that human women have evolved to be fertile over their likely lifespan but in recent times (past few thousand years) that lifespan has dramatically increased for a variety of reasons. So the answer to the question at the beginning of the parapraph is: People weren't really supposed to live that long.

I'm writing a post on a recent scientific paper, but am confounded by some of of the statistics given there and am hoping that someone can resolve the issue. I haven't read the paper (it's behind a pay wall) but Anthropology.net has some quotes. This is the one that's giving me trouble:

Although the X-chromosome contains only about 4.4 per cent of our DNA, with its estimated 1529 genes, it contains perhaps approximately 8 per cent of all human genes (Pennisi 2003; NIH 2007; Parang et al. 2008; NCBI 2009a). The dramatic differences in X-relatedness between grandmothers and grandchildren confound the Hamiltonian concept that grandchildren are 25 per cent genetically related to each grandparent. If approximately 92 per cent of our genes are autosomes, then a grandmother shares one-quarter of that, or approximately 23 per cent of her total genes with a grandchild, plus X-relatedness.1

If a grandmother shares no X-chromosome with a grandchild, then their overall genetic relatedness is approximately 23 per cent, and if they share an entire X-chromosome, then it would be approximately 31 per cent. Therefore, MGMs and grandchildren are likely to share 25 per cent of their genomes, while PGM and granddaughter may share a total of approximately 31 per cent of their genes, with a likelihood of 27 per cent inheritance, while a PGM and grandson may share only approximately 23 per cent.

These percentages don't gel with my calculations. A maternal grandmother passed on one X chromosome to her daughter, who gets the other from her father. That daughter will pass on an X chromosme to her children, and there's a 50/50 chance it will come from her mother. So the grandchildren will either have the grandmother's X chromosome and therefore share 31 percent of her genes, or not have her X chromosome and share 23 percent of her genes. Assuming straight statistics hold, the average is 27 percent (the paper says 25 percent).

As for the paternal grandmother, she passes on an X chromosome to her son. That son will definitely pass on that X chromosome to his daughter, so 23 percent random genes plus the eight percent X chromosome genes means 31 percent relatedness. What I don't understand is why there is "a likelihood of 27 per cent inheritance".

I would assume that the paragraph was wrong but it was published in the Proceedings of the Royal Society, and I would be shocked if they published something that was so blatantly wrong, so I'm hoping someone can point out my mistake.

The other options is that it's a misquote, but it appears to be cut-and-pasted. 

An interesting study has been done to add some data for those of a utilitarian mindset. About 10,000 Australians answered questions about their happiness and major life events since 2001, and this data has been mined by Paul Frijters to put some price tags on major life events.

I don't think he's published the results yet (just presented them at ANU), but from an SMH article:

• A marriage over a lifetime is worth $32,000 to men and $16,000 to women
• A divorce is equivalent to a man losing $110,000 and a woman $9,000
• The birth of a child over the parents lifetime is worth $32,600 to men and $8,700 to women.
• Death of a spouse or child is like a man losing $627,300 and a woman losing $130,900
• Moving house is equivalent to a man losing $16,000 and a woman gaining $2,600

This does raise several questions for me, and not the one raised in the article (which was why do men have a higher dollar figure on life events than women? Is it that they feel more, or that money isn't as important to them, or are their emotions more erratic?)

Variations In Answers

Fritjers notes that "insurance companies and lawyers take a keen interest in the research...because of the need for dollar compensation". However, these dollar figures are just averages; surely a long and happy marriage is worth more than a short and troubled one. In that case couldn't a person in a happy marriage argue for more compensation for the death of a spouse than a person in an unhappy marriage? I shudder to think of the courtroom antics if that was found to be of legal consequence. At the least it appears a woman would be entitled to less compensation for emotional distress than a man. I'm also interested if there are any other differences between groups, such as between socio-economic level, races, and so on.

Long Term Vs Short Term Happiness

A lot of these comparisons compare short term and long term things, for example: "What's a marriage worth? To an Aussie male, about $32,000. That's the lump sum Professor Paul Frijters says the man would need to receive out of the blue to make him as happy as his marriage will over his lifetime." How does he measure happiness over the lifetime? Is it cumulative or taken at the end? And if the survey has only gone for 8 years or so it seems a bit premature to be talking about lifetime effects. This may be addressed in his paper, of course, but I see great difficulties in these comparisons.

How About A Payoff?

If all this is true does it mean you could feasibly pay someone enough to stop them doing something? Would a woman accept $16,000 to call off her wedding, and never get married? Would they accept $8,700 in exchange for being sterilised so they couldn't have kids? I instinctively doubt this would be the case, and why is that? It could be argued people over-estimate the amount of happiness a particular event would bring them...or it could be something else.

Happiness Vs Joy

I make a distinction between happiness and joy, so I'll detail my definitions here. Happiness is temporary and superficial, it is giddy, it can even be created by drugs. Joy is long-lasting and profound, it can't be created by drugs, it includes within it satisfaction and contentment. A financial windfall may bring short-term happiness, but it very rarely brings long-term joy. On the other hand, a good marriage brings long-term joy (and usually quite a bit of short-term happiness), it helps people feel satisified and content with how their lives are going. A good example of this is the birth of a child:

The birth of a child turns out to bring both. It makes parents the happiest before it happens and then after some months slightly less happy than they would have been without the birth, which is why Professor Frijters puts low dollar values on the lifetime boost to happiness that flows from a birth - for the mother around $8700, for the father $32,600.

It's no surprise that people are less happy directly after the birth of a child (as I write this my baby is screaming, she wants to be fed again): There are extended periods of sleep deprivation, a sudden absence of quality personal time, a reduction in freedom of movement and so on. None of these things are conducive to giddy happiness. And yet, many people feel a quiet sense of joy as they feed their baby, or even change its nappy, because life isn't about being happy, it's about fullfilling a sense of purpose and long-term joy and satisfaction with what a person has done and how they've lived their life. If you disagree I hope you're on Prozac.

Related:

Putting A Price Tag On Life And Measuring Pleasure

Sure, it's simplistic, but what the hey. I also noticed you can choose an Australian political party, but the Democrats aren't on the list. Sad, but hardly surprising. Great policies, but completely useless as a political party.

Cate Burns has a good piece in The Age raising another point about Australia's exploding population. Specifically the trend of urban sprawl in Sydney and Melbourne. What is inherently wrong with expanding the size of those cities? They were built on some good fertile land to feed the early colonies, basically amongst the best places to grow food in Australia. Once those farms are paved over for poorly-designed McMansion suburbs a long way from services that source of food is going to disappear. I thought by now we'd be intelligent enough not to continue that sort of idiocy, but apparently not: "Now land in the Casey-Cardinia growth area is about to go the same way. This is high-quality agricultural land, with a combination of food soil, a ready and secure supply of recycled water from the Eastern Treatment Plant and close access to the Melbourne markets." So as well as lacking water for the increased population, it's going to be harder to feed them.

Related:

On Global Footprints And Population

The Major Challenges Facing Australia

Now Australia Also Heads For Overpopulation

The Government has issued an apology to the Forgotten Australians (SMH). More than anything else, this recognises what happened all those years ago, and hopefully will help in preventing it in the future. Hugh Mackay has written a piece arguing that an apology is useless, worse then useless, without corresponding forgiveness -- he may have a point but he wrote the article in such a way that it sounds like the apology shouldn't have been offered without a guarantee of forgiveness in return, which kind of defeats the purpose and makes the victims sound like the guilty party.

Now, I agree that forgiveness is important, even necessary, but it's also usually a work in process. People take time to completely forgive the wrongs done to them if the forgiveness is genuine (rather than just empty words). His call for "A formal act of forgiveness" is just foolish -- who's going to do that? Do each of the 500,000 people affected need to send in letters of forgiveness? Or can just one person make a blanket statement? And if so, who and on what authority?

It took a long time just to get the average person aware that white people were also unfairly put into homes, and then more time to convince them that they too had suffered abuse. I think it is that recognition that is important, so the victims don't feel voiceless and that their experiences didn't happen or were simply unimportant.

It will hopefully also lead to increased support for groups like Care Leavers of Australia Network, which does a lot of good in simply letting people know that they are not alone. When my mother went to her first meeting she came back astounded, saying that all these problems and issues and thoughts that she had which made her think she was a freak were shared by most people who were in those institutions. That is a signifcant step forward.

A friend of mine working on the space program sent me a list of "inspirational quotes" to justify space exporation. Now I'm all for space exploration for a variety of reasons. However, a lot of the quotes here didn't strike me as inspirational. I found a lot of the quotes to be indicative of the idea that humans are somehow evolving to meet a predestined goal -- one even suggested the push to space may be the result of biological determinism. Quite a few were of the "we've stuffed up the Earth, so we'd better find some other place to stuff up" variety. A lot of them work on the assumption that the only worthwhile goal for society is the continuation of the species by whatever means possible and at whatever cost.

The corollary to that was the idea that if humans did die off then everything anyone ever did was worthless and it's the same as if no-one had ever existed. For example, Asimov is quoted as saying: "why not take what seems to me the only chance of escaping what is otherwise the sure destruction of all that humanity has struggled to achieve for 50,000 years?" Another two people (Gregory Benford and George Zebrowski) are quoted this way: "All our history, all our social progress and growing insight will be for nothing if we perish."

I think this is a very sad philosophy to have. It's true that even if we maintain the Earth as habitable, and even if we prevent anything from crashing into it, as some point the sun is going to expand and swallow it. So, if we're in another solar system will that help? Only temporarily, that'll go too. And the galaxy, and eventually the entire universe. Rather than there being "no way now imaginable to kill off the human race" if we spread to other solar systems, the human species, in fact everything, is ultimately doomed if look forward into the future far enough. Does this mean that these people think that everything they are doing now is pointless?

For mine, I see everything people do as good or bad, useful or unuseful in its own right. The lives of people dead and gone weren't wasted and pointless if they're now unremembered or future events undid their deeds; they affected the people at the time, grew in wisdom and spread happiness (or vice versa), and were ends in themselves, not just the means to some undefinable ends in the distant future.

If you look further down there are some far better reasons -- I like the idea of taking the particularly environmentally damaging stuff off Earth. Although, we're still a long way from mass emigration, I really don't think it's going to help the population pressures. 

What's Space Travel Without A Little Risk? Nigh Impossible.

Everyone was appalled when Nidal Hasan snapped and killed 13 people recently. The SMH has a piece up noting that this is not much of an aberration: "On average, guns kill or wound 276 people every day in America. Of those shot, about 75 adults and nine children die."

For whatever reason America has the highest violent crime rate in the developed world. The SMH quotes Britain's Home Office which In 2000 "published a study that compared murder rates in the world's capital cities. Canberra had 0.64 homicides per 100,000 people. London had three times that rate. Washington, DC's, murder rate was 93 times that of Canberra's". Admitedly Canberra probably doesn't have the highest crime rate in Australia, but the trend is the obvious.

Now, what America does or does not do is its own business, but there's a good tidbit of an argument against loosening Australia's gun laws. After Martin Bryant killed 35 people in 1996 John Howard instituted "one of the tightest sets of gun ownership laws in the world". The result? "Australia endured 11 mass shootings in the decade leading to the day Bryant ran amok. There have been none since."

While researching something different I came across a useful tidbit of information when considering the size of Australia's population. The most recent projection put Australia's population at 35 million by 2050, and this growth is one of the major challenges facing Australia's future.

According to the Global Footprint Network (via Wikipedia) "the total world Ecological Footprint is 2.7 global hectares per person. With a world-average biocapacity of 2.1 global hectares per person, this leads to an ecological deficit of 0.6 global hectares per person". Obviously the richer nations have a larger footprint per person than the developing nations.

Australia's figures are 7.8 global hectares per person -- unsurprisingly far higher than the average. The good news is that the "ecological remainder" is 7.6 global hectares per person -- ie the amount of Australian land we're not using. An increase in population will obviously reduce this remainder, and as has already been pointed out the world's population is already using more resources than the world can replace. The best thing Australia can do is keep its population low and reduce the number of global hectares per person the population uses.