Daily Archives: March 12, 2009

Palaeowomaen: Barbara Isaac, Women in The Field, and The Throwing Hypothesis

The following post has been slightly revised in response to commentary below and elsewhere. I thank all those who commented for the helpful critique.

The question of diversity in science, and more specifically, success for women, is often discussed in relation to bench or lab oriented fields. If you read the blogs that cover this sort of topic, they are very often written by bench scientists, for bench scientists, and about bench scientists. Which makes sense because most scientists probably are bench scientists.

ResearchBlogging.orgBut a lot of scientists are fieldworkers, and the problems, challenges and potentials of fieldwork should be viewed, at least to some extent, separately because of different conditions that may prevail in those areas. I highly recommend that you have a look at these blogs for more discussion of issues faced by women in the field sciences:

Here I want to do two separate but related things. I want to discuss certain aspects of the nature of fieldwork in my area in the 20th century that have had a strong effect on the way women have pursued their careers (or not). Although I characterize this as the situation of the 20th century, this does not mean that the situation has or has not changed substantially since then. Simply put, I’m not discussing the current career related situaton for women in field paleoanthropology here in this post.

The second thing I want to do is to talk about a successful female social scientist with a strong connection to fieldwork in palaeoanthropology, as well as theoretical and administrative contributions. This person is also someone who straddles the boundary between classic mid- to late-Twentieth Century patterns of professional activity (in these field sciences) and more recent patterns. I’m speaking here of Barbara Isaac.

The link between these two topics is a bit tenuous but it is also meaningful. There is nothing stereotypical about Barbara Isaac’s career, and there is nothing short of admirable about her as a person and a scholar. My intention here is to not make strong links between these two parallel topics.
Continue reading Palaeowomaen: Barbara Isaac, Women in The Field, and The Throwing Hypothesis

The Origin of the Human Smile

i-292d5241115b67e27ce78512e86d1926-chimp_smile.jpgA colleague and grad student of mine, Rob, just sent me the following question, slightly edited here:

A student in my intro class asked me a good question the other day to which I had no answer. When did smiling cease to be a threat gesture? I have a couple of ideas. One is that with reduced canines, smiling became a way to say “look, I have small canines, I am not a threat to you.” The other is that smiling is based more on a “fear-grin” than a threat. Under this idea, smiling might have been a way of showing deference to others. If everyone shows deference, it would be egalitarian, until the one guy comes along who never smiles. Maybe that’s why bosses often don’t smile. … let me know when you have some free time to have lunch. Tuesdays and
Wed’s probably work best for me.

Good question, and good ideas as to a possible answer. I have a couple of other ideas to contribute….

(a repost)

Dare I say “It’s too bad that smiles don’t fossilize…” But really, if we started digging up smiles, that might make palaeoanthropology too weird to contemplate and fewer people would go into the field.

Since primates seem to use facial gestures like smiles and yawns to communicate emotional state and to negotiate social status, a comparative approach is reasonable. However, human emotions have been incorporated into a set of social relations that are very derived so this is difficult.

In The Face: A Natural History, Daniel McNeil refers to a study that shows that while judges are as likely to convict (or not) smiling defendants, the ones who smile get lighter sentences.

Smiling is innate in infants, and has obvious social implications in humans, but the role and nature of the smile … as far as what the mouth is doing while smiling … seem to have culturally bound variation.

Have you seen the movie Platoon? For a few years, some time before that movie came out, I had the pleasure of working with a number of Viet Nam vets (doing archaeology and historical research). I heard a number of stories from them over the years, and Platoon, interestingly, seemed to me to be a catalog of horrors experienced by most of the ground troops who spent a fair amount of time in that conflict. One of the events that happens in the movie involves a raid on a village suspected of harboring “Viet Cong” or stashing weapons. The Marines corner a young man and insist that he tell them where the bad guys and/or weapons are hidden. The young man is totally freaked out, but appears to be smiling at the Marines. This enrages one of the Marines, who eventually kills him.

What the Marine missed is that in the culture of that region, there is a facial expression that Westerners will often interpret as as smile, but it is in fact a grimace. The corners of the mouth are turned up and the teeth are showing, but there is nothing happy going on at all. We do see this in Western settings as well, just not as often. My daughter was perplexed a few months back when one of her friends seemed to be smiling while talking about the death of her father a day or two earlier. The girl’s emotions were clearly showing, but a negative expression appeared as a smile (at least that is what I think was happening).

The mouth-smile of primates is, in fact, usually a grimace and not a happy thing (as you point out). I think primates do different things to show that they are happy, and smiling may not be on the list.

A hard core evolutionary psychologists might suggest that s smile shows a state of health by showing a complete set of teeth, indicating normal development during childhood and that you have spent a life not making other people mad at you enough to knock out a few teeth.

I’m not sure I like the canine/no canine idea too much because that is a display that operates across broad phylogenetic differences. Consider analogues to this argument with other physical traits. Every time a whale pirouettes in the water it is demonstrating that it does not have those ancient land-mammal legs any more. I don’t think the other whales would be impressed. (I admit that might be an extreme example).

But here is what I think is the most important point: An evolutionary theory about smiling has to take into account the whole face (and perhaps more) and not just the lips and teeth. Look at this picture:
i-dd043713df73be0b845ef877e5482e6e-smiling.jpg

You can tell that this person is smiling and you can’t see her mouth. The eyes give it away. Meanwhile, you can tell that this person is not smiling:
i-01d0bd42a7c6b68e9fcef589615dafcc-notsmiling.jpg

By the way, the upper photo is a professional model. She is not necessarily happy, but she is really smiling. She is truly smiling because she is looking at something she truly loves (the camera). The ability to do this is what separates the professionals from the rest of us who always look like we are faking it when the person taking the picture with one of those horrid PHS digital cameras takes nine minutes to press the button while we stand there waiting.

Expressions can be important. They can even tell you what a member of another species is thinking, as has been demonstrated over and over again by the insightful LOL cat movement:
i-6d64822ef22db7742c26efe2380c9bf1-cat_eat_you.jpg

As for lunch, Wednesdays are good for me.

Update on Technology Chief vs. FBI

The FBI “raided” the Washington DC (city) office of Vivek Kundra, who is just finishing his term as Chief of Technology for the district. Kundra had been asked to to to the Federal Government to be the federal chief information officer.

Later in the day, the FBI agents arrested two people, a DC worker, Yusef Acar, and an employee of Advanced Integrated Technologies Corp, Sushil Bansal.

Reasons for the raid and the arrest are not currently known but should be soon because the two arrested men will be in court momentarily.

source: Faux News.

Morning Sickness is an Adaptation, not a … Sickness

There is new information from an older idea (from about 2000) by Paul Sherman and colleagues. The idea underlying this research is simple: Symptoms of illnesses may be adaptive. Indeed, this may be true to the extent that we should not call certain things illnesses. Like “morning sickness.”

ResearchBlogging.orgBroadly speaking, there are two different kinds of reasons that a woman may experience nausea in association with pregnancy. 1) This pregnancy thing is a complicated mess with all kinds of hormonal (and other) things going on, so you puke; or 2) a woman who is pregnant feels nauseous for good evolutionary reasons.

(a repost)

From an article in American Naturalist by Flaxman and Sherman:

“Morning sickness” is the common term for nausea and vomiting in early human pregnancy (NVP). Recent interest in why NVP occurs-that is, in the evolutionary costs and benefits of NVP-has spurred the development of two alternative hypotheses. The “prophylaxis,” or “maternal and embryonic protection,” hypothesis suggests that NVP serves a beneficial function by expelling foods that may contain harmful toxins and microorganisms and triggering aversions to such foods throughout pregnancy. The alternative “by-product” hypothesis suggests that NVP is a nonfunctional by-product of conflict-over resource allocation-between the pregnant woman and the embryo. The critical predictions of the prophylaxis hypothesis have been developed and tested, whereas the by-product hypothesis has not been subjected to similar scrutiny. To address this gap, we developed a graphical model and used it to derive predictions from the by-product hypothesis under two different assumptions, namely, that NVP is either (i) a by-product of current conflict between a pregnant woman and an embryo or (ii) a by-product of honest signals of viability produced by the embryo. Neither version of the by-product hypothesis is fully consistent with available data. By contrast, the timing of NVP, its variation among societies, and associated patterns of food cravings and aversions are consistent with the prophylaxis hypothesis.

In the prophylaxis, or more easily pronounced, “adaptive” hypothesis, a pregnant woman becomes hypersensitive to certain inputs (smell and taste of certain foods) that she should be avoiding for the health of her fetus. There are lots of things that typical adult humans can eat without causing harm that can do bad things to a fetus, especially during the first several weeks of development when organs are forming. Many plant products, for instance, are suspect.

After testing the two dominant theories (one adaptive and the other non-adaptive) for why two-thirds of women around the world — but seemingly no other mammals — experience nausea and vomiting in pregnancy, only one holds water, says Paul Sherman, Cornell professor of neurobiology and behavior and a Weiss Presidential Fellow.

“Our study, which tested theories and predictions about the nature of parent-offspring conflict in human pregnancy, shows that nausea and vomiting in pregnancy is beneficial by expelling such foods as meat and strong-tasting vegetables that historically and still may contain harmful toxins and microorganisms that could potentially sicken the woman and damage her fetus just when its organs are developing and are most vulnerable to chemicals,” said Sherman, who is an expert in Darwinian medicine — viewing diseases from an evolutionary perspective.

“Morning sickness” is rare after the first 18 weeks … the organ forming weeks … of pregnancy. Severe morning sickness is associated with lower rates of spontaneous abortion. The most pathogen-containing foods (historically, as in, pre-refrigerator) are those that tend to induce nausea in these women. Morning sickness is found more often in societies with risky foods as part of their day to day diet. And, this phenomenon … morning sickness … is only known in humans. Humans have a broad and, in terms of toxins, relatively dangerous diet.

This last part could be investigated further, I would think. There must be enough variation out there among omnivores to find some other species with morning sickness. Keep looking guys!

(I would add that slow development is another feature of humans that could be important.)

If the alternative theory that morning sickness is a non-adaptive outcome of an evolutionary tug-of-war between the mother and fetus for resources were correct, then the nausea should peak in the final trimester, when the fetus requires more nutrients and blood than at any other time. But it doesn’t. Neither does it occur with every pregnancy. If morning sickness were the result of the fetus signaling its viability to the mother, then all humans and other mammals should experience it.

“All this leads us to suggest that morning sickness is a misnomer,” Sherman said. “It doesn’t occur just in the morning, and it’s not an illness. It can occur any time of day and it appears to be beneficial — we could call it a form of evolutionary wellness insurance.”

Sources:

Flaxman, S., Sherman, P. (2008). Morning Sickness: Adaptive Cause or Nonadaptive Consequence of Embryo Viability?. The American Naturalist, 172(1), 54-62. DOI: 10.1086/588081

Press Release

The Evolution of Imprinting

ResearchBlogging.orgThe phrase “genomic imprinting” has come to refer the turning off of a gene (a particular instance of a gene on a particular chromosome duplicated across the cells in a body) so that the gene is not expressed at all, with the turning off of the gene not caused in the body in question, but rather, during the previous generation by a process happening in the soma of one of the parents. A maternally imprinted gene is passed on to junior, but will not be expressed in junior. a paternally imprinted gene is passed on to junior, but will not be expressed in junior. Typically (as far as we know) a gene is imprinted by neither parent, one parent (as in always the mother) or the other parent (as in always the father), but never both parents.

There is a little oversimplification going on here, but not much. “Imprinting” can happen through more than one mechanism, and as far as I know, at least one of these mechanisms has other functions and probably evolved early in the history of life for reasons that have nothing to do with paternal imprinting.

(a repost)

(I quickly add that since we don’t really know the exact mechanism for imprinting in mammals, we can’t rule out the possibility that a maternally imprinted gene is sometimes, even often imprinted by the male parent, and visa versa. But it is probably also true that having both genes imprinted is very problematic so these instances would either be well known rare disorders or, more likely, early aborted reproductive events. There is a handful of such disorders known and they are thought to related to incorrect chromosomal arrangements, not cross-sex imprinting.)

Although imprinting has been looked at a number of times and there are a few different models to explain its evolution, the most recent, well developed, and interesting explanations are those proposed by David Haig. Haig notes that imprinting is complementary with respect to a particular trait such that if an individual receives two imprinted genes or two non-imprinted genes (which would normally be impossible) for a trait in which imprinting happens, the associated phenotype is extreme. He then notes that the outcome of this trait would resemble (if the individual could survive with it) an extreme parental strategy suited to one, but not the other parent.

The classic example would be a trait that grew placental tissue. The placenta is an organ of the offspring. It is the first organ that you lose during your lifetime (later you’ll lose wisdom teeth, maybe an appendix, and if you buy a house, an arm and a leg, etc.). The job of the placenta is to extract energy from mom. From dad’s point of view, in mammals (which are internally fertilized) a good strategy might be to extract ALL of the energy from mom. Grow the baby big, fast, and strong, suck mom dry in the process, and it really does not matter if she can reproduce again. Dad has no real guarantee that the next baby to be nourished by this particular female is going to be his anyway.

From mom’s point of view, it is better to allow the offspring in utero to have just the right amount of nutrition via the placenta, so she can continue to invest (perhaps) in previously born offspring, and/or prepare for future offspring.

If there are genes that regulate the relative distribution of energy towards growth of the embryo exclusive of the placenta, vs. the placenta itself, then one might expect the pro-placental genes and the pro-embryo genes to “line up” with a parental unit, and/or the facility to turn on or off a gene by one parent to be offset by the other parent. And that is in fact what happens.

I’m skipping over lots of details here, but let’s just say that in mammals there seems to be genes turned off by dad vs. mom that, if either is reversed in its effect, the result can be as extreme as either all-placenta or all-embryo (neither of which is viable). There are a couple of in between conditions that probably involve a smaller number of genes being affected. Also, the extreme and non-viable versions of this sort of thing can be observed in mice by producing all-or-none fertilized eggs and combining them with normal eggs early in development to produce a chimera that is affected but viable.

So, in short, Haig’s theory is that imprinting evolves in the context of parent-offspring conflict (in relation to conflict among parents or potential parents).

The paper at hand, by Edwards et al., looks at the evolution of imprinting across mammals. Imprinting may be unique to mammals, but within mammals, is there a pattern?

From the author’s summary:

…Here we have shown that all the genes in one genomic region, Dlk1-Dio3, which are imprinted in placental mammals such as mouse and human, are not imprinted in marsupial (wallaby) or monotreme (platypus) mammals. This is in contrast to a small number of other imprinted genes that are imprinted in marsupials and other therian mammals and indicates that imprinting arose at each genomic domain at different stages of mammalian evolution.

The genes in this region are generally associated with the placenta.

I would argue that this supports Haig’s hypothesis. The non-placental mammals may have a different calculus for parental investment, and there are important mechanistic differences as well. With early separation (via an egg or an altricial offspring) females have enough additional control over offspring strategies for garnering nutrition from the mother that there are few paternal strategies involving maternal nutritive supply that can be exploited, and thus, a maternal counter strategy using imprinting need not evolve.

Edwards, C.A., Mungall, A.J., Matthews, L., Ryder, E., Gray, D.J., Pask, A.J., Shaw, G., Graves, J.A., Rogers, J., Dunham, I., Renfree, M.B., Ferguson-Smith, A.C., Ponting, C.P. (2008). The Evolution of the DLK1-DIO3 Imprinted Domain in Mammals. PLoS Biology, 6(6), e135. DOI: 10.1371/journal.pbio.0060135

US Technology Chief Office Raided by FBI?

Federal agents this morning are searching the Judiciary Square office of Washington, D.C.’s Chief Technology Officer.

The search is part of “an ongoing investigation,” said a spokeswoman for the FBI’s D.C. Field Office, Lindsay Gotwin, said. She declined to comment further.

The outgoing Chief Technology Officer, Vivek Kundra, was appointed last week Chief Information Officer by the Obama administration. His last day at the city government office was February 4, a spokeswoman for D.C. Mayor Adrian Fenty, Leslie Kershaw, said.

“We know the FBI is over there but that’s all we know,” said a staffer in the D.C. CTO’s office,…

Not many details yet.

When Kissing Cousins get to Third Base

ResearchBlogging.orgIt has long been known that incest is not as bad as you think. Anti-cousin marriage laws are like prohibition laws and blue laws. They arise from a Christian conservative movement that swept Western Civilization from the late 18th century through the 19th century, up to about the time of the repeal of Prohibition.

Sure, marrying, or just plain having sex with, your sibling is disgusting. I mean, think about it. No, wait, don’t even think about it. But cousin marriage? That depends. Your cousin may be kinda cute, you never know.

(a repost)

But seriously, anthropologists have long known of … and have had two distinctly different explanations for … patterns of marriage that involve linking up various kinds of cousins. At this point, let’s just say that cousin marriage tends to benefit … in terms of coalition formation, power management, and with respect to inclusive fitness …. the ascending (older, in charge) generation, even if it is no necessarily ideal for the marrying generation. This may well explain the pattern that we see: Prescribed cousin marriage is common in many scieties, but the degree to which it happens is at least somewhat correlated, it would seem, with he level of patriarchy. The more control older typically male power brokers have over things, the more people stick with cousin marriage. The less such power, the more rule breaking we see.

Forbidding laws are foreboding things. If you make a law that says that some behavior should never, ever happen, then people may become more fearful of the outcome of such actions. Cousin marriage laws instituted mainly during the last half of the 19th century have led to the general understanding that if cousin have a baby, it will have two heads. But in fact, and this has been known scientifically for decades, the increased rate of revelation of hidden recessive mutations in marrying cousins is small. It is about the same as a woman over 35 or so having a child.

A paper just out in PLoS Biology reviews the history of cousin marriage, its prohibition and the related controersy, in the West.

The conclusion is the following interesting conundrum:

…we note that laws barring cousin marriage use coercive means to achieve a public purpose and thus would seem to qualify as eugenics even by the most restrictive of definitions. That they were a form of eugenics would once have been taken for granted. Thus J.B.S. Haldane argued that discouraging or prohibiting cousin marriage would appreciably reduce the incidence of a number of serious recessive conditions, and he explicitly characterized measures to do so as acceptable forms of eugenics …. But Haldane wrote before eugenics itself became stigmatized. Today, the term is generally reserved for practices we intend to disparage. That laws against cousin marriage are generally approved when they are thought about at all helps explain why they are seemingly exempt from that derogatory label.

It is obviously illogical to condemn eugenics and at the same time favor laws that prevent cousins from marrying. …

Interesting, that link between religious belief and eugenics.

As a paper published in an Open Access journal, you can review it yourself. Do read this paper, it is well done and quite accessible.

Diane B. Paul, Hamish G. Spencer (2008). “It’s Ok, We’re Not Cousins by Blood”: The Cousin Marriage Controversy in Historical Perspective PLoS Biology, 6 (12) DOI: 10.1371/journal.pbio.0060320