Driving to work the other day we heard part of a story on the BBC about human economic behavior -- we heard the part about the behavior, but did not hear the part that told us what show it was, so, in what is very poor blogging protocol, we can't link to it. In any case, their 'expert' (undoubtedly an economics professor at some presumably respectable university, and thus expert at evolutionary biology) says that humans are always trying to outwit and outcompete each other, and that we're vulnerable to herd behavior in terms of what it seems will be good competition (like buying a house because everybody else is, assuming that even if there's a bubble, and it bursts, at least I will get out in time to profit).
As the yarn was spun, our expert said that we came from ape stock, small bands, simple life and all the usual stuff. Then we 'decided' to build complex systems like Wall Street (let's cut a break for the far-sighted implication that an ape foresaw New York), but our little ol' ape brains weren't capable of living in such a complex system. That's why our behavior is not up to it and why such a system as Wall Street doesn't actually work.
Now no doubt economists, who for some reason still have paying jobs at universities, acknowledge that they can't predict any better than weather forecasters, have all sorts of theories about why the system fails, leads to such personal tribulations, high unemployment, etc. etc. And the Beeb interviewee went on about similar kinds of things.
So we have the very ethnocentric Just-So story that we're over our li'l heads in complexity and that's why things don't work! But wait just a second! To the ear used to accepting baloney Just-So stories, this sounds acceptable. But there is a much more plausible explanation, far more evolutionary in fact than these contorted post hoc evolutionary make-believes. Evolutionarily, our economic system is either irrelevant, or it works wonderfully!
After all, there are by far, far, far, more people on earth, and hence more copies of 'the' human genome, than ever before. There may have been a total of less than 200 billion people ever, in the past hundreds of thousands of years of human history, but 7 billion of those -- around 5% -- who ever lived, are alive to day, and in terms of reproduction we're putting bunnies to shame.
No evolutionary biologist has any reason to make any connection between Darwin and whether people are enjoying life. Indeed, Darwin rested his theory on his belief that life was miserable, relentless, cruel competition. So, even if we accept the economist experts completely at their word about our non-rational behavior, we are, as a species, booming along just fine!
From this point of view, it matters not a whit if you are unemployed, lose your house, or can't get good health care. So long as you and your descendants are rutting merrily away, the economic system is working wonders, whether you're happy with it or not. And if economic woes lead to even less 'responsible' sexual behavior, that's evolutionarily even better!
It's a wholly legitimate question why we can't understand economics. But it's not an evolutionary question about whether humans are adapted to our culture or not. Our economic behavior must fit within our biological nature, and of course there will be genetic variation that affects it--and even some genetic variants that have detectable effects. But the behavioral 'repertoire' is not restricted to humans.
Economic behavior is evolutionary, but it's cultural not biological evolution that matters. And the fact is, social scientists including cultural anthropologists have failed rather seriously either to simply recognize there are serious limits to knowledge, or that their knowledge is seriously limited, or that their profession's achievements are fundamentally under-developed. That's where the problem lies, and the proof is in the pudding.
Showing posts with label BBC. Show all posts
Showing posts with label BBC. Show all posts
Tuesday, May 24, 2011
Wednesday, July 1, 2009
Vegetables and you
Today's big health news (or, at least, headline)? A vegetarian diet prevents cancer! A study of 60,000 people in the UK, published in the British Journal of Cancer, reports that vegetarians get less cancer of the blood, bladder and stomach. Of 100 meat eaters, 33 will eventually get cancer, while of 100 vegetarians, 29 will do so. If we feel a need to point out that this difference is rather unimpressive, the study does seem to have been independent--at least, it was not paid for by the carrot and broccoli industry! But, vegetarians are more than half as likely to get cancers of the blood and lymph, although the actual number of most cancers, in this sample, was quite small.
The protective effect of the vegetarian diet isn't always true, however--cervical cancer is higher among vegetarians than in meat eaters, though the number of cases was very small, and bowel cancer was slightly higher among those who don't eat meat (contrary to decades of reports that meat-eating, for various reasons having to do with bacterial metabolism of animal fat, increased colorectal cancer).
What mechanism do the authors suggest to explain their findings? Perhaps there are viruses or mutation-causing compounds in meat, or protective compounds in vegetables. Indeed, at least stomach and cervical cancers are known -- and this knowledge does seem to be real! -- to be caused by viruses.
However, something that at least the BBC write-up of the story doesn't point out, a notorious problem with these kinds of studies that should always be pointed out right at the top, is the problem of environmental confounding, in which one measure is correlated with an unmeasured factor. In that case, it is wrong to attribute causation to the former.
It should be clear even to the most obtuse that vegetarians and meat-eaters probably have different life styles in all sorts of ways, which may increase or decrease their risk of exposure to causative environments, having nothing at all to do with diet itself. In this case, diet is merely a marker of life style and risk, not a causative factor, and indeed the study does nothing to control for any such differences. Maybe the dedication of vegetarians to things like Zen meditation affects cancer risk!
Most interestingly, one of the authors of the study was interviewed on the BBC radio program, Newshour, this morning with a fascinating lead-in. Owen Bennett-Jones, the interviewer, pointed out that dietary findings come and go, often being contradicted by subsequent findings--red wine protects against cancer, or it doesn't, dietary fat causes breast cancer, or it doesn't--so why should we believe the results of the vegetarian diet study?
The author himself acknowledged that the findings are not earth-shattering, and may eventually be contradicted, and may only apply to vegetarians in the UK, and these were small numbers of each cancer anyway. He quite burst his own balloon, albeit with the help of his interviewer. His rationale is that after smoking, everything else is a minor risk factor. But, apparently this shouldn't stop researchers from spending large amounts of taxpayer money to look for these minor effects anyway. And hyping them to the media. Hmm. Maybe the vegetable industry should pay for this research!
Bennett-Jones played this story well. He had a science journalist on along with the scientist, and he asked her why so many unreliable stories appear in the media. She said the explanation is very easy--health news sells, especially when it's scary and about cancer. She blames the hype on scientists for wanting to publicize their iffy findings, the industry for wanting to promote the latest food that will prevent cancer, and the media for having to fill the papers and airwaves on deadline. Literally every day, she said, she gets calls from the food industry, or scientists, wanting to tell her about their latest findings.
So, follow a vegetarian diet if you choose to. But don't do it because of the promise that it will prevent cancer.
Fittingly enough, there's a story in the New York Times today, by Gina Kolata, updating us on yesterday's big health news, which suggested that c-reactive proteins, a marker of inflammation, cause heart disease. People were already developing tests for CRPs, counting on the promise that CRPs, rather than cholesterol, were causative and thus were going to need to be tested for in everyone, multiple times. But a new study in the Journal of the American Medical Association, suggests that, yes, CRPs are associated with heart disease, but are not causative.
Interestingly, this study uses a relatively new epidemiological method called Mendelian randomization to show that some people are genetically predisposed to make more CRPs than others, but that CRPs levels themselves aren't associated with heart disease. This is an appropriate use of genetic data.
Well, we have to go now. It's time for lunch. We wonder what's on the menu today.....
The protective effect of the vegetarian diet isn't always true, however--cervical cancer is higher among vegetarians than in meat eaters, though the number of cases was very small, and bowel cancer was slightly higher among those who don't eat meat (contrary to decades of reports that meat-eating, for various reasons having to do with bacterial metabolism of animal fat, increased colorectal cancer).
What mechanism do the authors suggest to explain their findings? Perhaps there are viruses or mutation-causing compounds in meat, or protective compounds in vegetables. Indeed, at least stomach and cervical cancers are known -- and this knowledge does seem to be real! -- to be caused by viruses.
However, something that at least the BBC write-up of the story doesn't point out, a notorious problem with these kinds of studies that should always be pointed out right at the top, is the problem of environmental confounding, in which one measure is correlated with an unmeasured factor. In that case, it is wrong to attribute causation to the former.
It should be clear even to the most obtuse that vegetarians and meat-eaters probably have different life styles in all sorts of ways, which may increase or decrease their risk of exposure to causative environments, having nothing at all to do with diet itself. In this case, diet is merely a marker of life style and risk, not a causative factor, and indeed the study does nothing to control for any such differences. Maybe the dedication of vegetarians to things like Zen meditation affects cancer risk!
Most interestingly, one of the authors of the study was interviewed on the BBC radio program, Newshour, this morning with a fascinating lead-in. Owen Bennett-Jones, the interviewer, pointed out that dietary findings come and go, often being contradicted by subsequent findings--red wine protects against cancer, or it doesn't, dietary fat causes breast cancer, or it doesn't--so why should we believe the results of the vegetarian diet study?
The author himself acknowledged that the findings are not earth-shattering, and may eventually be contradicted, and may only apply to vegetarians in the UK, and these were small numbers of each cancer anyway. He quite burst his own balloon, albeit with the help of his interviewer. His rationale is that after smoking, everything else is a minor risk factor. But, apparently this shouldn't stop researchers from spending large amounts of taxpayer money to look for these minor effects anyway. And hyping them to the media. Hmm. Maybe the vegetable industry should pay for this research!
Bennett-Jones played this story well. He had a science journalist on along with the scientist, and he asked her why so many unreliable stories appear in the media. She said the explanation is very easy--health news sells, especially when it's scary and about cancer. She blames the hype on scientists for wanting to publicize their iffy findings, the industry for wanting to promote the latest food that will prevent cancer, and the media for having to fill the papers and airwaves on deadline. Literally every day, she said, she gets calls from the food industry, or scientists, wanting to tell her about their latest findings.
So, follow a vegetarian diet if you choose to. But don't do it because of the promise that it will prevent cancer.
Fittingly enough, there's a story in the New York Times today, by Gina Kolata, updating us on yesterday's big health news, which suggested that c-reactive proteins, a marker of inflammation, cause heart disease. People were already developing tests for CRPs, counting on the promise that CRPs, rather than cholesterol, were causative and thus were going to need to be tested for in everyone, multiple times. But a new study in the Journal of the American Medical Association, suggests that, yes, CRPs are associated with heart disease, but are not causative.
Interestingly, this study uses a relatively new epidemiological method called Mendelian randomization to show that some people are genetically predisposed to make more CRPs than others, but that CRPs levels themselves aren't associated with heart disease. This is an appropriate use of genetic data.
Well, we have to go now. It's time for lunch. We wonder what's on the menu today.....
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