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Tag Archives: Human sexuality
Catching Fire. The other one.
Catching Fire
You can pick up a copy of our paper on this page. We call it “The Cooking Hypothesis.” The basic idea can be summarized with these points:
1) Cooking food transformed human ecology. Many potential foods in the environment can’t be consumed by humans (or apes in general) without cooking. But adding cooking to our species-specific technology, we can access those foods effectively transforming our ecology to a much greater extent than the vast majority of evolutionary transitions, especially single-event transitions, have ever done. The total number of calories in the natural environment that become available to an ape that can cook goes up by orders of magnitude.
2) This increase in available calories left a biological signal that is very impressive. Two major changes happened in the hominid body (in early Homo erecuts/ergaster). One is an approximate doubling in body size from an earlier Australopithecine or “Early Homo” ancestor. The other is a reduction in tooth size. Less eating equipment with a body demanding so much more in energy to grow and maintain signals a fundamental change in the food supply. There may be more than one way this could have happened, but so far adding cooking to our technology seems to be the best explanation.
3) Related, this is when we see brain size, relative to body size and in absolute terms, increase. Neural tissue is picky, expensive, and costly. Having a significant increase in brain size may be related to the demands (on the brain) of adding cooking to our behavior in that the size increase is allowed by the extra energy. And, it may be related in that the larger brain may provide the capacity to have this behavior.
4) The actual act of cooking, as a technology, may or may not demand a larger brain. But the process of cooking almost certainly involves central place foraging (bringing all the food back to one place, much of the time, to cook it) and delayed consumption (as opposed to eating the food where you find it). The basic pattern for a chimpanzee-like ancestor is to eat the food where you find it. Bringing food into close proximity to other members of your group virtually guarantees direct competition for food, which makes getting to food to begin with a highly questionable thing to do. In order for cooking to work, the social interactions typical of an ape have to be modified significantly. Cooking demanded, facilitated, and made major changes in social structure “worth it” from the point of view of natural selection.
5) These changes in social structure are probably indicated as well by changes in stone tool technology. Early cookers also were early hand-ax makers, for example. Human ancestors went from making primarily expedient, one time use, very simple stone tools to making tools that required a great deal of investment in time and energy to learn the technology, get good at it, and even for the production of individual tools (including acquisition of better than average raw materials in many cases). Once the tools were made they seem to have been used, often, for long periods of time. It is hard to imagine a chimp-like creature carrying around a tool into which she invested time and energy without it being taken away. This is an important transformation.
6) Less visible but very likely is a change in social system which could be called the rise of proto marriage. Sexual arrangements of a human-like kind are very different than for chimp. The ability to allow others to possess food or invest in more sophisticated technologies may be parallel to the ability to have more or less exclusive sexual contracts among individuals. This is indicated independently in the fossil record by a large decrease in sexual dimorphism in body size. In polygynous species like chimps males are often much larger than females, and this seems to have been the case with pre-Homo erectus/ergaster ancestors. But at the same time the body size increase and tooth size decrease happen, we also see a reduction in sexual dimorphism in body size, strongly indicating a major change in social arrangements. The best two explanations for this may be a shift to a gibbon-like pattern of paired-off monogamous adults living more or less alone, or a human-like pattern of paired-off monogamous adults living in larger social groups.
It is an idea that would have caught on. It would have selected for more nuanced communication, and may thus have facilitated the origin of what we now know of as human language and symbolic processing.
So when you are eating your Thanksgiving dinner this year, most of which will be cooked, look around at the people at the table and, briefly, imagine them to be chimps. Then go back to your meal and try to put all those thoughts aside…
How Do You Get Sexual Orientation and Gender in Humans?
Humans appear to have a great deal of variation in sexual orientation, in what is often referred to as “gender” and in adult behavior generally. When convenient, people will point to “genes” as the “cause” of any particular subset of this diversity (or all of it). When convenient, people will point to “culture” as the “cause” of … whatever. The “real” story is more complicated, less clear, and very interesting. And, starting now, I promise to stop using so many “scare” quotes.
Continue reading How Do You Get Sexual Orientation and Gender in Humans?
The Kiss
Valentine’s Day is coming up, so it is time to think about kissing. Pursuant to this, Sheril Kirshenbaum, author of “The Science of Kissing,” has made the Kindle version of her excellent book available at a discounted price through February 18th. The book is here: The Science of Kissing: What Our Lips Are Telling Us
I went out with a friend. We were both between relationships, and we both knew somehow that this was a date though it was never called a date. And we had a perfectly good time: Good food, good conversation, good drinks. She drove.
When it came time to go home, she drove me to the urban neighborhood I lived in and parked on the street near my house. As we were saying our good-byes, she enigmatically unhooked her seat belt. I wondered why. Then, I discovered that she wanted the freedom of movement to lean across the console and give me a kiss. It was a good kiss. It was actually a series of good kisses, and it went on for a while.
And suddenly, there was a loud rapping on the window of the car. We stopped kissing and that’s when we noticed that we had steamed up the windows a bit. So I cracked the window on which the rapping had occurred and there was a policeman staring in with his flashlight.
Continue reading The Kiss
Falsehoods: Human Universals
There are human universals. There, I said it. Now give me about a half hour to explain why this is both correct and a Falsehood. But first, some background and definition.
Continue reading Falsehoods: Human Universals
What is the most important human adaptation?
Human infants require more care than they should, if we form our expectations based on closely related species (apes, and more generally, Old World simian primates). It has been said that humans are born three months early. This is not accurate. It was thought that our body size predicted a 12 month gestation, and some suggested that Neanderthals would have had such, but this research conclusion has been set aside based on new analysis. But it is still true that developmentally, human children do not reach a stage of development that allows some degree of self care for a very long time compared to apes. The actual sequence of development is not directly comparable: It is not the case that after a certain amount of time humans reach a specific stage reached earlier in the lifecycle by Chimpanzees, as the differences are more complicated than that. For the present purposes, we can characterize the human condition for early development like this: Human babies are more helpless in more ways and for longer than comparable ape babies.
Continue reading What is the most important human adaptation?
Why do women shop and men hunt?
Or, when the hunting season is closed, watch teh game (the guys), or when there are no sales, admire each other’s shoes (the gals)?
This is, of course, a parody of the sociobiological, or in modern parlance, the “evolutionary psychology” argument linking behaviors that evolved in our species during the long slog known as The Pleistocene with today’s behavior in the modern predator-free food-rich world. And, it is a very sound argument. If, by “sound” you mean “sounds good unless you listen really hard.”
I list this argument among the falsehoods, but really, this is a category of argument with numerous little sub-arguments, and one about which I could write as many blog posts as I have fingers and toes, which means, at least twenty. (Apparently there was some pentaldactylsim in my ancestry, and I must admit that I’ll never really know what they cut off when I was born, if anything.)
Before going into this discussion I think it is wise, if against my nature, to tell you what the outcome will be: There is not a good argument to be found in the realm of behavioral biology for why American Women shop while their husbands sit on the bench in the mall outside the women’s fashion store fantasizing about a larger TV on which to watch the game. At the same time, there is a good argument to be made that men and women should have different hard wired behavioral proclivities, if there are any hard wired behavioral proclivities in our species. And, I’m afraid, the validity from an individual’s perspective of the various arguments that men and women are genetically programmed to be different (in ways that make biological sense) is normally determined by the background and politics of the observer and not the science. I am trained in behavioral biology, I was taught by the leading sociobiologists, I’ve carried out research in this area, and I was even present, somewhat admiringly, at the very birth of Evolutionary Psychology, in Room 14A in the Peabody Museum at Harvard, in the 1980s. So, if anyone is going to be a supporter of evolutionary psychology, it’s me.
But I’m not. Let me ‘splain….
Continue reading Why do women shop and men hunt?
Sex at Dawn
From Skeptically Speaking:
We talk to author Christopher Ryan about his new book Sex at Dawn: The Prehistoric Origins of Modern Sexuality
. We’ll discuss the most recent science and theories, and how social norms compare to our biological impulses.
This Friday. Details here. I may have to read this book.
Science: There is no g-spot, so stop looking for it!
In a recent study, 56 percent of the women interviewed in a sample of 1800 claimed that they had a “g-spot” which is an area inside the vagina with increased sensitivity with respect to sexual arousal.
(Added: See THIS write up of the original research)
Continue reading Science: There is no g-spot, so stop looking for it!
Stealing Genes and Hypergyny
This post was originally titled “Mail Order Brides and Hypergyny.” I was prompted to revisit the post because it received a a rather astonishing comment that I chose not to allow, but I did post it on my Facebook page where any attention it would receive would be from the thoughtful people that make up my Facebook community rather than just anybody out there on the Internet. Also, I recently received a complaint from a reader that Scienceblogs.com has been showing a lot of ads for “mail order brides,” and this post was originally partly a response to that.
I should also mention that in the years between 2009 and 2014 it is possible that the term “mail order brides” has been legitimately problematized. I don’t know that it has, it just seems like it must have been. For example, Wikipedia says “The term “mail-order bride” is both criticized by owners (and customers) of international marriage agencies and used by them as an easily recognizable term.[2] It has been pointed out that there is a discrepancy between how international adoptions are regarded (“saving a child”) and how international marriages are regarded (“buying a wife”).” citing Lilith, Ryiah (2000–2001), Buying a Wife but Saving a Child: A Deconstruction of Popular Rhetoric and Legal Analysis of Mail-Order Brides and Intercountry Adoptions 9, Buff. Women’s L.J., p. 225F Schaeffer-Grabiel (2005), When the mail-order bride industry shifted from using a magazine. If you have any comments on that please leave them below.
Original Post, Mail Order Brides and Hypergyny:
Seymour had a mail order bride and he was very proud. Seymour was a night watchman that I got to know because I was forever lurking around at night, passing through alarmed doors and making a nuisance of myself and, usually, keeping just one step ahead of Seymour, who’s main objective in life was to find a reason to throw me out of the building. The one time he actually had the drop on me, found me without ID, with no instructions that people would be working late in the lab, on a weekend that people were not supposed to be in the building because of work being done on the fire alarm system, he made his move and told me to get out or I’d be arrested.
I had no choice.
I engaged in a conversation with Seymour, which no one had ever done before, and after a half hour he went way forgetting that his main goal in life was to throw me out of the building. But in the mean time, I learned about his mail order bride. From Korea.
I’ve noticed that Scienceblogs.com has been running ads for hot Russian mail order brides. These ads are rather funny on the surface; They seem to be parodies of such things that they represent. But if you click on one (and I certainly did … expecting to end up at The Onion) one learns that this is the real thing. These are real ads for real Russian women who really want to marry you. If you are Seymour.
I’ve told you before that I mostly avoid commenting on the advertisers for Scienceblogs.com. Hear no evil, see no evil, speak no evil. One of the most evil corporations on the planet is one of our sponsors, and no one ever seems to notice or complain. My blog is editorially independent (as are all the other scienceblogs.com blogs) and I am free, if I choose, to blog against the big evil corporation, and in fact, have done so to a limited extent.
At first, I found it rather shocking that none of my fellow Sblings seem to be blogging about the mail order bride ads. Then I realized that they must all be using ad blockers.
For my part, as you may have noticed, almost everything I encounter lately seems to remind me of a story from the Congo. (I wonder why that is?) So I can tell you a little about hypergyny in the Congo.
Let’s get two things straight:
1) Mail order brides are participating in hypergyny. Hypergyny is where females (gynos) marry “up” (hyper).
2) You will see the term “hypergamy” used and that is simply incorrect. There can be no such thing as hypergamy as a practice because that means everybody marries up. How would that work? The term is “hypergyny.”1
Hypergyny can occur in a lot of different cultural systems, and in fact wherever there is a) differential wealth and b) males tend to control big hunks of that wealth and the associated power (and no, it is NOT all about power … wealth and power are historically interchangeable enough that we should be cautious about making such distinctions) there will be hypergyny because there will be women who either choose it or are forced into it. In this form, and exploiting the ongoing conversations about rape, hypergyny can be understood by reference to the sexual interactions between allied forces liberating Europe from the Nazis and the local women. In Italy, Allied men tended to rape the women. In France, the women seemed happy to sleep with the men. For food. The difference? Well, lots of things were different, but to oversimplify somewhat, there was a big difference in how much people were starving at that particular moment between Italy and France.
Hypergyny is sleeping with the man over a longer term. For food and everything.
The most benign form of hypergyny of which I am aware (not counting mail order brides …. I’m not sure where I want to put that phenomenon on any scale of severity) is that found among the Efe Pygmies (and other Pygmies) in Central Africa.
Here, there are two integrated but distinct cultural entities: Villagers and Foragers. The Villagers are not Efe. They may be Bantu or Central Sudanic speakers (where I worked, they were Central Sudanic Lese). Villagers are farmers who often hunt, Efe are both foragers and farm laborers. The fact that there are material overlaps between the cultures does not make these cultures overlapping in all ways, or hard to distinguish, or flexible in membership. They are as solidly different as any caste might be.
The rules: Any Villager man and woman can marry. Any Forager man and woman can marry. Any man may have more than one wife.
A Villager woman can never marry a Forager man, but a Forager woman may marry a Villager man.
Often, but by no means always, the Forager woman who marries a Villager man is a second (or maybe even third) wife of that man, in a polygynous marriage.
If a Forager woman marries a Villager man, they live in the village as villagers. The woman takes on the cultural trappings of the village much more than other Forager women do. The children are Villagers. If the woman leaves her husband and goes back to the forest, she can not take the children with her. They remain as villagers.
The women can decide to do this or not. Their decision is usually a matter of personal lifestyle preference. The forest means freedoms not available in the village and you get to go camping all the time, and there are rich cultural traditions that live mainly in the forest, and that is where your family is. In the villages, you get a roof that will hardly ever leak.
One of the effects of this system is that men among the Foragers marry on average quite late owing to the a shortage of women.
In this way, there is a slow and steady gene flow from Forager groups to Villager groups, which led me to propose some years ago the Gene Stealing hypothesis. The relationship I describe here occurs in many different places and times. It seems to occur more often in tropical regions, and it seems to occur virtually all the time where the indigenous group (in this case the Forager) is hypergynous to the invading group (in this case the Villagers, who moved into the area hundreds of years ago).
The invading group is not adapted to local disease to the extent that the indigenous group is. But they can ensure that among their children there will be an elevated rate of such adaptation, by coming up with this pattern. This works much better than just killing off the locals or driving them out. You take their genes but keep them distinct as a locally adapted specialist group.
Indeed, there is evidence that something like this may have happened in the middle east with the Natufian culture, and I’ve wondered about the relationship between Modern Humans and Neanderthals in this regard.
I know, I know, that is a long way from pictures of Hot Russian Babes that may or may not be in the right sidebar.
Or maybe not….
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1There is a way in which hypergamy, which is widely used much to my annoyance, makes sense: If you have hypergyny and hyperandry, then the two together could be hypergamy, much like polyandry and polygyny are polygamy. But that is not what is going on with these terms.
China Sex Theme Park
Sexual topics are largely taboo in China, so as a result, many people walk around not knowing what they really need to know about this important topic. Recognizing this problem, the Chinese Government has decided to build a huge, totally OTT sex theme park. Presumably all Chinese citizens will be required to go and enjoy this park.
China is building what is billed as its first sex theme park, aimed at improving both the sex education and the sex life of its visitors.
Due to open in Chongqing in October, Love Land will include displays of giant genitalia, naked bodies and an exhibition on the history of sex.
The park will also offer sex technique workshops and safe-sex methods.
More emotional intelligence = more orgasms
According to a study just coming out in the Journal of Sexual Medicine, “variations in emotional intelligence–the ability to identify and manage emotions of one’s self and others–are associated with orgasmic frequency during intercourse and masturbation.”
Grasping the function of the human penis
Gallup has taken on the task of explaining, in ultimate terms, the evolutionarily designed features of the human penis. He works this as an engineering problem from the perspective of evolutionary psychology, which is always a little bit dangerious, but gallup isn’t quite the arm waiver that a lot of other EP’s are, so he may be doing it right.
Gallup’s work is written up an an all-too-sophomoric Scientific American article by Jesse Bering which just barely falls short of explaining this important biological phenomenon in terms of a pair of headlights, a flashlight, and a little red waagon.
Here’s the money quote:
Magnetic imaging studies of heterosexual couples having sex reveal that, during coitus, the typical penis completely expands and occupies the vaginal tract, and with full penetration can even reach the woman’s cervix and lift her uterus. This combined with the fact that human ejaculate is expelled with great force and considerable distance (up to two feet if not contained), suggests that men are designed to release sperm into the uppermost portion of the vagina possible. Thus… “A longer penis would not only have been an advantage for leaving semen in a less accessible part of the vagina, but by filling and expanding the vagina it also would aid and abet the displacement of semen left by other males as a means of maximizing the likelihood of paternity.”
The other component of the work is the intriguing possibility that penises have evolved to carry semen previously left in one female’s vagina from another male to be deposited hours later in the vagina of a second female. Which I suppose could be called facilitated cuckoldry.
I’ve not read the original paper yet. I’m not quite up to it. But if I do, I’ll let you know if it is truly a seminal work, or if Gallup is just jerking us around.
The curious case of penile vaginal intercourse and depression in women
I’m starting to worry that the last few Friday Weird Science write-ups by Scicurious (who seems, these days, to be the primary blogger at Neurotopia) have been of papers that I happen to have read. Just so you know: Thousands of papers are published per week across the diverse sciences, and although Scicurious tends to deal with life science and I tend to read life science, the chances of this particular harmonic convergence across bloggers regarding papers published over the last decade is statistically almost zero. More likely, Scicurious and I just have similar taste … or lack thereof.
The latest paper written up by Sci is on the relationship between certain kinds of sexual intercourse and reduction of depression in women, suggested by a study by Gordon Gallup and others.
Continue reading The curious case of penile vaginal intercourse and depression in women