RS>> Today we are very lucky to have as our guest speaker Professor Ron Wetherington from the Anthropology Department and I don't know the title of today's talk but I'm certain that it will be interesting. Ron, all yours.
...
RW>> First a word from our sponsors. I'm offering, for the first time, Forensic Anthropology this spring. Anyone who is interested, it's a CF course, a 3000 level. Either as ANTH or as CF: identification of human remains, determining sex, estimating age, classifying race and ethnic group, establishing time of death, identifying cause and manner of death, distinguishing the kinds of trauma, from blood spatter to bone scatter (that's a neat one), courtroom testimony and ethics, etc. There will be weekly case studies and a weekly mystery bone. So if any of you are interested, it's going to be offered from 3:30 to 5:00 on Tuesday / Thursday. It's Anth 3351. OK. And you can contact me if you're interested in further information.
So this is the subject of what I'm going to talk about.
["There is something fascinating about science. One gets such wholesome returns of conjecture out of such a trifling investment of fact." --Mark Twain]
I don't have a title, but I'm going to talk about something that you've already engaged in and that is how one authenticates information and how one identifies facts from fancy, how one distinguishes whether what is said or what is written down is reasonable or not reasonable.
So let me just begin by asking you if you were given a statement, say you read it somewhere, yeah let's say you read it. And I won't say where you read it and the statement is something like, oh I don't know, say, the likelyhood that you have inherited a mutation is 37.5%, something like that. What do you, before you actually accept this, what do you do to determine whether or not this is something that is probably true, something that you will accept as the truth or something that you will simply throw away as being nonsense. What do you do first to determine that? And it may be unconscious.
S>> Consider the source?
RW>> OK. Consider the source. So therefore if the source is a scientist, rather than a novelist, you'd probably be more inclined to accept it. Say the source is impeccable and the source is a scientist. What more?
S>> The sample and the size of the sample?
RW>> OK. What sample of occurrences of mutation and what was the size of the sample that was used to determine this? Now, let's say that the sample size was 5000. Would that be... Would you say, well, that's reasonable? 10,000?
S>> It would still depend on where the sample was coming from.
RW>> OK. Let's say the sample is a blind sample, random sample from patients in five metropolitan hospitals: New York, San Francisco, Chicago, Miami, and Dallas. And it's randomized as to sex; it's randomized as to age. As a matter of fact, it's a grab sample from whoever happens to be in the hospital, so therefore the hospitalization has nothing to do with that probability. Would that be acceptable?
S>> You have to figure out what they mean by "inheritable mutation" because it could be a difficult thing to pin down.
RW>> It's something that is identified on a chromosome, from a karyotype.
S>> So we're talking about a particular mutation?
RW>> No, we're not talking about a particular mutation at all. We're talking about any mutation that is found on a chromosome.
S>> Well the problem is that defining a mutation on a chromosome is a really difficult thing to do because there could be mutations at any point on the germ line and you can't really determine ...
RW>> OK, now let's say that you read another article that says that the little organism, amphioxus, represents a new sideline of evolution rather than a direct evolutionary link in the development of the central spinal cord.
Anybody familiar with amphioxus? In high school, you usually dissect the amphioxus because it's the first animal that has a central nervous system with a spinal cord. And let's say that this article says that it does not belong to the category that it has ever been placed in. Now what would your response be?
S>> By what criteria?
RW>>OK. Would you want to...would you... Comparing these two, would your acceptance of one be more important to you than your acceptance of the other?
So you'd just as soon know what your likelyhood is of having the mutation as whether amphioxus belongs in the class that it was always put in?
S>>I'd be more concerned with the mutation.
RW>> Sure. and Why? It affects you directly.
S>>Having a mutation, I mean, genotypically doesn't mean anything phenotypically ...
RW>>No, but it certainly means what your children might have.
S>>Well, as a mutation is just a mutation and if it doesn't affect you then it won't affect your children either. It would have to be multiple mutations in order to have an ending result.
RW>> No, no. If you have... the probability that you have inherited a mutation 37, what did I say?, 37.5%, if you have inherited it...
S>> A mutation as in .. are you saying, like, that you're a carrier of something?
RW>> If you have inherited it that means that mutation is in every cell of your body, including your germ cells, including your sperm cells, and therefore you have a likelyhood of transmitting that mutation on.
S>>By mutation do you mean something like, say, achondroplasia, where...
RW>>Sure.
S>> A lot of mutations never come up...
RW>>Obviously it depends on whether that mutation is recessive or dominant. Things like this. But the point is that if you have inherited a mutation then that mutation has a high likelyhood of being passed on because that mutation is that one pair of loci of all the genetic loci in your body and that one pair, half of the time one of them is going to go to your offspring and half of the time the other one is, so that half of your offspring are going to have that mutation. They'll inherit it.
So obviously if our conventional understanding that such a likelyhood is less than 5% is turned over now that that likelyhood is 37.5% then that's something that we need to confirm. That is to say, I would want to know if this is actually the case and I would want to support funding for early diagnosis before I have children. But with amphioxus, I couldn't care less.
Because amphioxus doesn't affect me at all. The point here is that we are more often likely to accept statements of "fact" (quote unquote) that affect us in one way or another than we are to accept something that doesn't affect us. And yet it seems to me that we are more likely to accept without question those kinds of statements that affect us than we are any other kind because if it comes from a scientific source, if it comes from a scientific journal, if it comes from an authority in the field, not just a scientist, but a scientist whose specialty is what he's talking about (because you have to be careful, scientists talk about everything and they're only specialized in certain things), then we're more likely to say that's got to be true, or that's probably true.
And let's take the case if that statement is hidden in the middle of a whole bunch of other statements which are less questionable, which are less controversial. We find this all the time, so let me give you three examples and these three examples come from real life cases.
The first one is a book that was published last year called Dragon Bone Hill by Noel Boaz and Russell Ciochon. They are both anthropologists who have solid reputations and Dragon Bone Hill is the primary place outside of Beijing in China the site of Zhoukoudian where Homo erectus, one of our ancestors, has a relatively large deposit of bones and skulls and so forth, and so this area has been studied for a long time. Dragon Bone Hill: an Ice-Age Saga of Homo erectus. Now, right away you know that this is a book intended for popular consumption, rather than for the scientific community because it's got a snappy little title, it sounds like it's going to be a study of mystery, of mystique, and yet the two authors are well known established physical anthropologists.
Now here's what, among other things that are concluded in here, here's what they say: After studying fossils in a region called Dragon Bone Hill in China, anthropologist Russell Ciochon (University of Iowa) concluded that males of the species were clubbing one another over the head, probably to win females. Now we've all seen that image before, right? Stone-age man with a big club, dragging the female by the hair, I mean that's that whole sexual dichotomy of authority and violence and power and so forth. He goes on: Those with thicker skulls who survived these bloody confrontations would pass that trait to offspring. So in other words if you had thick skulls, then you would probably survive the clubbing and go on to reproduce. The evidence shows there may have been ritualized violence taking place. There is this kind of ritualized violence known, for example, among the Yanomamo in Brazil where they have ritualized axe fights and they'll club each other over the head and cause blood to flow, but very, very seldom is there any death. For more than a hundred years, researchers have pondered the odd shape of Homo erectus' skull which looks something like a bicycle helmet. Indeed it does.
[pic]
OK. This is Homo erectus' skull. If you were to take a cross section of that skull, it would be quite thick. The brow ridges are fairly heavy. It's even been estimated that the brow ridge serves as protection against blows, as well as the thick skull, so it's like a bicycle helmet: squashed down, elongated, designed to protect the brain, eyes, and ears from impact. Homo erectus' head was bulkier than those of hominids before it and after it. Bulkier than those of hominids before it and after it, not thicker, bulkier.
That means simply that the skull of Homo erectus was larger because the brain was larger than those of preceding forms such as Australopithecus and so forth and so on. It wasn't bulkier than those after it because Neanderthal, which had brains that were our size, had thick skulls also, so it wasn't until 100,000 years ago or so that the skulls lost their thickness.
In their book, Ciochon and Boaz say that they would (quote) lay bets that, as in many other species, we are detecting the results of sexual selection (end quote). In the rugged world of Homo erectus, a tough skull served them well, scientists said. It would have been a tremendous advantage for survival, less likely to break on impact, and geared toward winning fights. With no language... With no language, only a shaky knowledge of fire, and simple stone tools, Homo erectus managed to survive for more than one and a half million years. Over the years, other explanations for thick skulls didn't completely add up. For example, the skull could not save them from the major predator of the day, the giant hyena, because hyenas would likely have aimed for softer, more vulnerable spots on the Homo erectus body and the animals' fierce teeth could easily pierce the thickest pre-human head.
The researchers used modern tools to reach their conclusions, studying fossil casts, fossil bones, ethnographic records and comparative anatomy. They experimented (you're going to like this) they experimented with human cadavers to establish how much force it would take to break bones. They gathered evidence from dozens of fossils with healed skull fractures, presumably from the hard heads who got the girls. Researchers compared the mating rituals of the hominids to those of bighorn sheep who charge each other at speeds up to 20 mph and butt heads for the right to mate with females. So why didn't modern humans inherit this thick skull? Ciochon said evolution eventually favored a lighter skull to accommodate a heavier and larger brain. A thinner skull would also help cool the brain.
Did any of you note how many statements of supposition were involved in this? How many conclusions, based not upon demonstrable fact, but simply based upon an observation of the data for which that conclusion as well as 14 others could be given as the conclusion?
Now the problem with this is that we are not given, as laypersons reading this, we are not given enough armament to determine whether or not some of these are factual and others are not. In other words, these are all statements; some of them are statements of fact which we know; others are statements of speculation. Some of the speculations are shared by a wide number of authorities and some are shared by very few. Obviously the broader a speculation is shared the more likely we are to accept that speculation as being true. In fact, that is one of the danger points in reading science. The number of authorities who agree that a speculation makes sense should not be a key to our acceptance of that speculation. A speculation has to stand on its own merits, not on the merits of the weight of authority that lays behind it otherwise there would be a lot of things that we would be believing in: the flat earth, the earth-centered universe instead of the sun around which the earth rotates and so forth. But let me just point out a few of these.
First of all, his conclusion that we finally lost our thick skulls because evolution eventually favored a lighter skull to accommodate a heavier and larger brain. But for evolution to favor a lighter skull, means that there must have been a change in the ritual so that people aren't banging their heads anymore. Because if they were continuing to bash heads to get females, the evolutionary trend towards thinner skulls would have gotten all of them killed. So that doesn't hold much water. That is to say, it's not very reasonable unless they can explain why, with a larger brain and a thinner skull, we also lost the head banging ritual.
A thinner skull would also help cool the brain. Well, first of all, we're dealing with all of our ancestors that grew up during the Pleistocene when temperatures were a lot cooler than they are today. Most of these are living in the northern latitudes, near glaciation. Cooling the brain wasn't a matter of concern. Furthermore, insulation of the brain by thick skulls against increased cooling or even increased heat, will also be a consideration. We know from the development of the brain itself that the sinus pattern of the brain changed as it grew to enable better heat loss through channels that don't depend upon the thickness of the skull. So much for that.
Why would they compare mating rituals to the bighorn sheep? Do we have any relationship to bighorn sheep? That is to say, the assumption here is that if other animals participate in this kind of ritualized competition, then isn't it likely that humans would too? You know, our evolutionary relationship to the bighorn sheep lies somewhere between zero and one and a half percent. So we could not have shared anything in common with them, certainly not this kind of ritual. I mean, after all, the mating ritual of the peacock has bright tails and dances by the males to enhance the female's attraction. Well, we do that too, you know. Does that mean that we share in common the peacock's behavior? So they're jumping a little bit here.
With no language, only a shaky knowledge of fire, and simple stone tools, Homo erectus managed to survive for more than one and a half million years. First of all, that's sort of a nonsequitur. It doesn't have anything to do with the skull unless it was the thick skull that allowed them to survive that long but, in fact, we have never confronted and spoken with Homo erectus. And so we don't know whether Homo erectus could answer us or not. I've sat in front of a Homo erectus skull for hours and he's never said anything to me and never answered. But that's because he's not alive so consequently that's not a fact that we need to worry about. And so what we're left with is a speculation that is a result of a quick leap of faith from the observation that there are thick bones whose function could not be protection against predators, because the predators could easily dispatch them by grabbing the softer parts of the body, and indeed mostly predators do. And so we're looking for another explanation for the thick skulls and that explanation comes from this ritualization. Well, in fact, the thickness of skulls starts at about two million to two and a half million years ago and it comes on down to one and half million years ago or less. And so we have a continuity of skull thickness as a part of the anatomical features of early evolutionary transformation and the skull gets thinner as the brain gets larger, but only substantially later than Homo erectus, so there must be some relationship, but that relationship can probably be better explained by internal explanations. That is to say, biological explanations rather than behavioral explanations. You may or may not agree with that, but I think you'll agree that we're talking about speculation for which they don't present good hard evidence that would convince us.
The next one is one in which the speculation is buried in a bunch of facts. Here is a fact. A genetic mutation that occurred 2.4 million years ago could be the reason why modern humans have such big brains and weak jaws, scientists said on Wednesday. This is back in March of this year. They discovered that a fault in a gene called MYH16 in modern humans happened about the same time that their skulls started to change in shape from other primates, allowing their brains to increase in size, but the tradeoff was a smaller, less powerful jaw. The coincidence in time may mean that the decrease in jaw muscle size and force eliminated stress on the skull which released an evolutionary constraint on brain growth.
OK. Now, the fact is they have identified this MYH16 mutation. It is a mutation whose normal form occurs in all the higher primates and it helps to mediate the synthesis of proteins that increase the size, the growth of jaw muscles. And as you know the nonhuman primates all have very heavy jaw muscles. As you know also, if you've read anything about fossil humans, that all of our earliest ancestors from 6 million years ago down to about 2 million years ago likewise had massive, heavy jaws and large teeth. And so that particular mutation, which as a mutation that decreases the amount of protein synthesized in order to reduce the size of the muscles in the jaw, obviously would only occur as the jaw itself got smaller. Now that suggests that the mutation occurred in response to the need for smaller jaws. In fact, mutation is random. That mutation was probably around for ages and ages, millennia after millennia, but it was disadvantageous and therefore it was eliminated as soon as it occurred. But once the jaw starts getting smaller, then there is an advantage to having less muscularity and that advantage now would accrue to the gene mutation that's still mutating just as it had been millions of years before but now that mutation is not disadvantageous and therefore it has a favorable selection. OK? So there is nothing wrong with that and this is in effect what they're saying. They imply the opposite but this is in fact what they're saying and it says all humans have the MYH16 mutation but other primates, including chimpanzees and macaques, still have the intact gene. OK, and that is true over the past few million years. Since the genetic fault the mutation occurred, humans skulls have grown three times in size and the outwardly elongated jaws have receded. That also is true. Now is this a coincidence or is there a relationship? Well, one would think that there was probably a relationship because we have the mutated gene which is now not a mutation but a normal gene in humans. We have the unmutated gene which is a normal gene in the higher primates and, of course, we don't know what it was in all of our ancestors because we can't extract the genes from the bones that are that old. But here's the statement: remarkably, the timing of the appearance of this genetic alteration or mutation roughly coincides with the appearance of human-like characteristics in the human fossil record. And the scientists said that the weaker bite, smaller jaw and weaker bite, would have lessened the force on the skull so it could grow larger and provide more space for a bigger brain. Now here's where they take the leap from fact to fancy. First of all, the suggestion is that a larger brain could not grow under the constraints of a heavy jaw. I mean here's what we have. We have a heavy jaw -- and we'll just use the same one as we have here -- a heavy jaw which muscles come up like this and it's a heavy patch of muscles comes all the way to the top and we have in modern humans muscles that come up about here and you can feel where those ... they're the temporalis muscles, and you can feel where they are. They're right here, ok? They don't go any higher than that and they're relatively small. But here in our ancestors and also in the great apes, we have muscles that go all the way up to the top of the head, sometimes causes a shelf to grow up here, a little crest, because there's not enough skull space for the muscles to attach. So obviously those are heavy, heavy muscles manipulating a very heavy jaw. And so is it likely that that heavy jaw with the heavy muscles provides a constraint on brain growth? That is to say, as long as those muscles are there they're holding the skull in and keeping it from growing. Now that's what they say. And therefore the mutation which reduces jaw size and muscle size, or at least muscle size in response to jaw size, released the restraints, would have lessened the force on the skull, and provided more space for a bigger brain. Releases the constraints on brain growth. Then if that is the case, that doesn't explain how the brain grew up through two and half to two million years ago, almost doubled in size from 400cc as an Australopithicene to 800 cubic centimeters as a later robust Australopithicene with still the very, very heavy jaws and even a sagittal crest. If the skull doubled in its size and the brain inside doubled in its volume, without any change whatsoever in the muscles, so there must be some critical point at which the skull can't grow any more as long as there are heavy muscles. But that doesn't make sense. That doesn't make sense because, as a matter of fact, there is every reason to want a larger skull so that the muscles have more surface area to attach. And the form of the skull on the outside is not going to have any relationship, to any great extent, to the volume of the brain on the inside and so there is no logical reason for making that kind of a leap in faith. And yet, when you read the article (and this is in a very acceptable medical journal), what you find is no distinction between the conclusion regarding the age of the mutation and the presence of the mutation in humans but not in apes and the conclusion that explains the coincidence between the mutation and the reduction in jaw size. Right? So could it not be more logically explained that, in fact, the jaw size reduced as the brain was expanding because we had then acquired cultural mechanisms to take the place of the heavy jaws? Those cultural mechanisms included preparing food in a way that didn't require the kind of ripping and tearing. It also included social organization and rules of conduct that reduced the amount of predatory violence that would take place. And so therefore the jaws were adapting to a dietary change into other kinds of adaptive changes that had nothing to do with constraints imposed by some erstwhile mutation that caused the brain to keep its growth down. But one cannot make that distinction unless one knows a little bit about what is going on here.
Is this OK so far?
OK here's the last one:
RS>> Ron, how did that article get past the peer-review process?
RW>> Well, because it says Stedman and his colleagues said the weaker bite would have lessened the force on the skull. That's true. It would have lessened the force on the skull. So it could grow larger and provide more space for a bigger brain. This is incidental to their .. to the purpose of the article. And so I think it got by because they said well that's just their speculation and they're not trying to demonstrate that this is the case. I think that's the reason.
OK. Anybody ever seen that book? The Probability of God. This is a book that is written, and here's the subtitle if you can't read it in the back -- a simple calculation that proves the ultimate truth. Stephen Unwin is a statistician and he is a statistician who by his own admission had been looking for some time to find a way to prove the existence of God. Dr. Unwin said he was interested in bridging the gap between science and religion. He argues that rather than being a theological issue, the question of God's existence is simply a matter of statistics. Of statistics. A scientist has calculated that there is a 67% chance that God exists. 67% chance. He has used a two-hundred year old formula to calculate the probability of the existence of an omnipotent being. Bayes' Theory (Bayes' Theorem actually, it says Theory) is usually used to work out the likelyhood of events such as nuclear power failure by balancing the various factors that could affect a situation. That is to say, you have two columns, column A -- all the factors in favor of, column B -- all the factors against. Factors that were considered included recognition of goodness, which Dr. Unwin said makes the existence of God more likely, countered by things like the existence of natural evil. Natural evil, including earthquakes and cancer. First of all, the use of the term "evil" as a value-laden term to a natural event is an oxymoron. Right? A natural event is neither good nor evil; it just is. OK? But anyway he has column A, column B. The unusual workings which even take into account the existence of miracles are set out in his new book which includes a spreadsheet of the data used so that anyone can make the calculation themselves, should they doubt its validity. The Manchester University graduate who now works as a risk assessor in Ohio said the theory, the theory now, on the probability of God starts from the assumption that God has, at the very beginning, base, a 50-50 chance of being. OK, so before you even start calculating, there is a 50-50 chance that God exists and then the factors in the evidence both for and against are piled together and calculated and so the "for" that is to say the existence of good, slightly outweighs evil, and therefore it raises from 50% to 67%.
What's wrong with that?
JC>> Where did he get the 50%?
RW>>Yeah. Where? How do we know to begin with? I mean an atheist is not going to say ... or an agnostic, sorry, who doesn't know, OK? An agnostic is not going to say, well there's a 50-50 chance.
S>> What's the definition of God?
RW>> Oh, he doesn't... An omnipotent being is what he says. An omnipotent being. But if you start with a 50-50 chance, then obviously any weighting factors that you put on that 50-50 chance are going to influence a change upward or downward, but if you start with a zero percent chance, then you're going to come out with a totally different probability. If you start out with a 100 percent chance, and you're going to pull in the statistics that reduce that likelyhood, then you'll come out with something different, but it's where you start with that obviously creates the first dilemma, and how do you know to start with 50-50?
S>>And also God's infinite and we're finite, how can you determine that we have the constituative number of factors necessary to calculate that probability?
RW>> Sure. On what basis can we judge the difference between good and evil as evidence for the existence of God. I mean that assumes God has nothing to do with evil, that as long as evil exists, God does not. And therefore the amount of evil that is reduced is an increased likelyhood of the existence of God.
S>> Does it say what the guy in Ohio's job is?
RW>> Well he's a data analyst right now but he taught .. he got his degree at the University of Manchester and taught statistics in Ohio then he became a risk assessor in Ohio. And a publisher decided that this was worthy of publication. For $22.95 you can confirm. Now obviously, I'm sort of chiding him in this case although he is no worse than what Ciochon is doing and what other scientists do when they step beyond the basic data and draw conclusions because all conclusions are based upon a rational balancing of the evidence and some of those conclusions are worthy of the evidence-- they may be wrong, but they're worthy of the evidence -- and some of them are internally flawed, and the ones that I've given you here are internally flawed because they assail the logic of anatomy or genetics which we already know. But others are more subtle than that. Who's the physicist down in Rice who wrote the Theory of Everything? There obviously are variations in the amount of expected acceptance from scientific conclusions. And we have the problem for those that matter to us. You know, amphioxus doesn't matter, so I don't care whether it's right or wrong (I mean I do care as a scientist) but for things that impact us we have a duty to go beneath the surface and scrape the bottom and find out on the basis of what data, what sample size, what procedures, what methodology, these conclusions were drawn and then we have to say (not being specialists) that in fact the methodology seems reasonable, that the conclusions are therefore conclusions that could logically come from that methodology and then we're one step closer to being scientifically knowledgeable instead of laypersons who simply accept anything that a scientist says as being correct.
JC>> You also want to know the assumptions that went into it?
RW>> And for every one of these, there are assumptions I mean like for example the assumption of the 50-50 chance but there are assumptions about everything and as a matter of fact, if you haven't already guessed this, that science is based upon the same quantity of assumptions, presuppositions, as religion is. That is to say, nontestable, nondeterminable presuppositions. We assume that there is order in the Universe rather than chaos. We assume that all reality is phenomenological, that we can see it, feel it, taste it, measure it. We assume that there is no action at a distance. That every effect has a cause. We make these assumptions, but in fact if there is telepathy which deletes that idea of cause and effect then our entire basis for science is questioned. So we make a lot of assumptions in science that we assume to be true and we don't question them because we can't test them, and then from that point on we base our scientific conclusions and there's nothing we can do about that but we can always question those assumptions.
Thank you.