Well, this doesn’t count as wildlife, but it does refer to the excretory habits of one species of primate. As contributor Athayde Tonhasca Júnior notes, ” I strongly suspect that this subject has not been approached before in your website. . . ” Indeed! Apparently these are loo-related photos from his travels.Athayde’s notes are indented, and you can click on the photos to enlarge them.
A visit to the toilet (room), bathroom, restroom, washroom, or lavatory, is an opportunity for reflection and introspection, or to seek refuge, peace and quiet. Indeed, British men allegedly spend seven hours per year in the toilet hiding from their wives and children (according to “research” commissioned by a bathroom furniture company). But the loo – or bog, can, head, john, or latrine – can also be a place of amusement and learning.
A flamingo on duty to check your hand-washing technique in Bologna, Italy.
Unfortunately this educative and lyrical message was removed from a dentistry practice in Perth, UK:
A health warning in Scots, which is a language, a dialect or bad English, depending on who you ask (and their political views). The UK government and the European Union recognise Scots as a minority language, but many linguists place it somewhere on a dialect continuum. To the chagrin of nationalists, Scottish heavyweights Adam Smith and David Hume considered the use of Scots as an indication of poor education.
An emergency cord is great, but what if you want to order a pizza or dry your hair while bombing the bowl? (Hotel in Padua, Italy):
My travelling companion was displeased with the facilities in a Padua cafe. Squat toilets are terrible for the elderly or disabled, but they have a great advantage: you don’t need to touch anything. You learn to appreciate them when you hear the call of nature in the back of beyond. They are also better for your health, supposedly:
A latrine in the Housesteads Roman Fort, Britain, on the northernmost edge of the Roman Empire. Year 200 AC:
Marcus: Salve, Quintus.
Quintus: Ave, Marcus. Are you well? You look a bit green around the gills.
Marcus: Tell me about it. I think that batch of garum from Rome was off.
Quintus: I hear you.
Cornelius: I hear you too, Marcus. Loud and clear! Ha-ha! Say, chaps, wouldn’t you have a spare sponge on you?
A tersorium (a sea sponge on a stick) supposedly used by the Romans to wipe themselves after using the latrine. The sponge may have been washed in a gutter with running water, or in a bucket of water, salt and vinegar. But not everyone agrees with this popular tale (kids love it). According to Gilbert Wiplinger (Austrian Archaeological Institute), the tersorium may have been nothing more than a toilet brush. Read his gripping account in the Proceedings of the International Frontinus-Symposium on the Technical and Cultural History of Ancient Baths, Aachen, Germany, 2009.
Sign in a loo in an antechamber of Perth’s Sheriff Court House. One must be at rock bottom to shoot up before facing a sheriff (a Scottish judge with powers to fine or lock you up for up to five years). For the last seven years, Scotland has maintained the unenviable first place in Europe for drug-related deaths; drugs in Scotland have a death rate almost four times the rate in the UK as a whole. These figures – together with failing education, economy and health indicators – are secondary for people in power. The one-track-mind Scottish National Party cares for little else besides breaking up the union:
Epiphany inside a loo in Perth, UK:
The facilities in the family home (today a museum) of Brazilian painter Cândido Portinari (1903-1962) in the town of Brodowski, São Paulo State, illustrate a time when homes were not cluttered with stuff and had plenty of space to spare:
Collector, philanthropist and extremely rich Ema Klabin (1907–1994) needed the loo to store some of her many priceless pieces of art. Her house in São Paulo is a museum (Fundação Cultural Ema Gordon Klabin) well worth visiting. Entrance is free:
A replica of a once common warning to men in public urinals, hotels and railroad stations in the UK. Not doing-up all the buttons of your trousers (no zippers then) was a grave indiscretion:
That’s not nice. At all:
Able young non-pregnant adults can use the loo in the petrol station across the road:
In a cafe in the Brazilian coastal city of Ubatuba, you are not allowed to flush yourself. Presumably to prevent polluting the sea:
“Use the toilet as you have committed a crime: don’t leave clues behind” (loo in a São Paulo bookshop):
Every day, it seems, I hear that “races have no biological reality or meaning; they are purely social constructs.” And that statement is somewhat misleading, for even the crudely designated races of “white, black, Hispanic, and East Asian” in the U.S. are, as today’s paper shows, biologically distinguishable to the point where if you look at the genes of an unknown person, you have a 99.86% chance of diagnosing their self-identified “race” as one of the four groups above. That is, if you ask a person how they self-identify as one of the four SIRE groups (SIRE: “self identified race/ethnicity), and then do a fairly extensive genetic analysis of each person, you find that the groups fall into multivariate clusters.
More important, there’s little deviation between one’s SIRE and which genetic cluster they fall into. Over 99% of people in the sample from this paper can be accurately diagnosed as to self-identified race or ethnicity by looking at just 326 regions of the genome.
This in turn means that there are biological differences between different SIREs, so race cannot be simply a “social construct.” This is in direct contradiction between the extreme woke view of “race”, as expressed in the Journal of the American Medical Association, a statement I discussed in an earlier post:
Race and ethnicity are social constructs, without scientific or biological meaning.
Nope, and we’ve known that statement is wrong for nearly 20 years. Of course, if you take “biological meaning” as “data show that there are a finite number of distinct groups with huge genetic differences”, then it is a correct statement. But nobody thinks that any more except for racists or those ignorant of modern population genetics in humans.
The meaning of the biological reality adduced in papers like the one we’re discussing today is this: genes can be used to diagnose biological ancestry, which is surely involved in one’s SIRE. And therefore “races” or “ethnicities” aren’t just made-up groups, but say something about the evolutionary origin of group members.
As I said, the “old concept” of races as a small number of genetic groups that differ strongly in their genes is dead. But there are still groups, and there are groups within groups, and groups within groups within groups. Thus genetic variation in our species is hierarchical, as expected if variation among groups evolved in geographically isolated populations, between which there was some but not complete mixing.
This view of human variation leads me to abandon the use of the word “race” in general and use “ethnicity” instead. I’ll use “race” in this article, though, as I’m addressing the JAMA statement above, and also using individuals’ own diagnosis of their own “race”.
. . . . the paper of Rosenberg et al.,. . . shows that the genetic endowment of human groups correlates significantly with their geographical location (for example, if you choose to partition human genetic variation into five groups (how many groups you choose is arbitrary), you get a pretty clear demarcation between people from Africa, from Europe, from East Asia, from Oceania, and from the Americas. (To show further grouping, if you choose six groups, the Kalash people of Asia pop up). This is one reason why companies like 23 And Me stay in business.
This association of location with genetic clustering (and these geographic clusters do correspond to old “classical” notions of race) is not without scientific meaning, because the groupings represent the history of human migration and genetic isolation. That’s why these groups form in the first place. Now you can call these groups “ethnic groups” instead of “races”, or just “geographic groups” (frankly, you could call them almost anything, though, as I said, I avoid “race”), but they show something profound about human history. The statement in bold above could be used to dismiss that meaning, which is why I consider that statement misleading.
The Rosenberg et al. paper was published two decades ago, and since then we are now able to look at more genes (potentially the entire genome of individuals) and use bigger samples over smaller areas. When we do that, we’re able to see the clusters within clusters. Here’s a reference to a 2008 paper:
Even within Europe,a paper by Novembre et al. reported, using half a million DNA sites, 50% of individuals could be placed within 310 km of their reported origin and 90% within 700 km of their origin.. And that’s just within Europe (read the paper for more details). Again, this reflects a history of limited movement of Europeans between generations.
I wanted to delve a bit into the 2005 paper of Tang et al. (mentioned in my earlier post), because it concentrates on self-reported race or ethnicity, not geographic origin, but also looks at variation over space. geography. Click on the title below to read the paper (pdf here and reference at bottom).
Tang et al. got their data from a study of hypertension in which individuals gave blood and also indicated their self-identified race as one of the four groups mentioned above. Then, each of the 3,636 individuals (taken from 15 geographic locales in the U.S., and three from Taiwan) were analyzed for 326 “microsatellite” markers—short repeated segments of DNA. (These segments may not all be independent because of genetic linkage, but certainly a lot of them are independent. The authors don’t discuss this issue, which is relevant but not invalidating.)
Tang et al. then determined whether the microsatellite data fell into clusters using on multiple genes and the clustering algorithm “structure”—the method also used by Rosenberg et al. to show ethnic variation was correlated with geography. Remember, the Tang et al. study took place mostly in American populations, with each SIRE sampled from several places. But the geographic sampling within the U.S. was limited (e.g., “Hispanics” came from only one place in Texas), and this is a potential problem.
Tang et al. did indeed find clustering using multivariate analysis: here are the clusters for all sites and SIRE combinations. Note that there are four clusters: one each for self-identified Caucasians from 6 populations (upper left), East Asians from 7 populations (middle right), African-Americans from 4 populations (lower left), and self-identified Hispanics from a single location (“K” from Starr County, Texas). Clearly we need more data from self-identified Hispanics from other areas, especially because “Hispanic” can denote many diverse ancestries.
The clusters are pretty distinct. Not only do are they distinct, but they match almost perfectly an individual’s self-identified race or ethnicity. As the authors note:
Of 3,636 subjects of varying race/ ethnicity, only 5 (0.14%) showed genetic cluster membership different from their self-identified race/ethnicity. On the other hand, we detected only modest genetic differentiation between different current geographic locales within each race/ethnicity group. Thus, ancient geographic ancestry, which is highly correlated with self-identified race/ ethnicity—as opposed to current residence—is the major determinant of genetic structure in the U.S. population.
As I said earlier “there is almost perfect correspondence between what “race” (or ethnic group) Americans consider themselves to be and the genetic groups discerned by cluster algorithms. Because these are Americans, and move around more, the genetics reflect ancestry more closely than geography, though, as Novembre et al. found, in Europe geographic origin is also important. Americans move around more than Europeans do!I
In other words, individuals within a cluster are more geographically dispersed than what Novembre et al. found, so that membership in a cluster indicates ancient ancestry, not geographic origin. For example, members of the “East Asian” cluster come from Taiwan, Hawaii, and Stanford.
But to show that there are clusters within clusters, so that “East Asian” can’t be considered a “race” in the old sense, the authors repeated the cluster analysis using only the East Asian sample, and found that those of Chinese ancestry formed a cluster distinct from those of Japanese ancestry. This is expected if self-identified ethnicity still reflects genetic differences that evolved in Asia. You would doubtless find similar relationships if you dissected Caucasians or African-Americans by the location of their ancestors.
What this shows, then, is that in the US, and in a limited sample of populations whose members self-identified their “race” into one of four groups, those groups can be differentiated using multiple segments of the genome. Not only that, but the differentiation is substantial enough that if you had an individual’s genetic information without knowing anything about them, you could diagnose their “self identified race/ethnicity” with 99.86% accuracy.
The take-home message:
In the U.S.—and in the world if you look at the Rosenberg study—one’s self-identified race, or race (again, I prefer “ethnicity”) identified by investigators—are not purelysocial constructs. Ethnicity or race generally say something about one’s ancestry, so that those members of the same self-identified race tend to group together in a multigenic analysis.
Note that this does not mean that there is extensive genetic differentiation between self-identified races. The old conclusion from my boss Dick Lewontin that there is more variation within an ethnic group than between ethnic groups remains true. But there is enough genetic difference on average that, if you lump all the genes together, the small differences accumulate sufficiently to allow us to diagnose a person’s self-declared race. Remember, these are “self-declared” groupings, so you can’t say they are imposed on the data by investigators. (That of course doesn’t mean that they aren’t social constructs. They may be in some sense, but they’re also social constructs that contain scientific information.)
So, the big lesson is that the JAMA was wrong: if races/ethnic groups can be diagnosed with over 99% accuracy by using information from many bits of the genome, then the statement “Race and ethnicity are social constructs, without scientific or biological meaning” is simply wrong. Race and ethnicity, even when diagnosed by individuals themselves, do have scientific biological meaning: namely, they tell us about an individual’s ancestry and where their ancestors probably came from. This is true in the U.S. (this paper) or worldwide (the Rosenberg et al. paper). Further, if you look on a finer scale, as Novembre et al. did, you can even diagnose what part of Europe a European’s ancestors came from (it’s not perfect, of course, but it’s pretty good).
This is not a new conclusion, and the papers I’ve cited are older ones. There may be newer ones I haven’t seen, but I’d be willing to bet that their results would be pretty much the same as that above. Though genetic differentiation between groups is not large, it’s sufficient to tell us where they came from, confirming that geographic origin (reflecting ancient geographic isolation) is the source of what we call ethnic or racial differences.
Just remember this: when you hear that human race/ethnicity is a purely social construct, and doesn’t say anything about biology or evolution, that’s just wrong.
I shouldn’t have to point out that these genetic differences in no way buttress racism, for we don’t even know what they mean in terms of individual traits. But they do give us insights into evolutionary history. And that is something of scientific and biological meaning.
Physicist Brian Greene published the book below in 2020, and it appears to cover, well, just about everything from the Big Bang to consciousness, even spiritually and death. Click image to go to the Amazon site:
I’ll try to be brief, concentrating on Greene’s view of free will, which is that we don’t have it, we’re subject only to the laws of physics, and our idea of free will is an illusion stemming from our sense that we have a choice. The interview with Greene is in, oddly, the July 1 issue of Financial Review, and is paywalled, but our library got me a copy. (Judicious inquiry may yield you one, too.) You might be able to access it one time by clicking below, but otherwise ask or rely on my excerpts:
Greene also dwells on the fact that we’re the only creatures that know that we’re going to die, an idea that, he says, is “profoundly distressing” and in fact conditions a lot of human behavior. More on that below. Here are a few topics from the interview:
Free will: Although Greene, as I recall, has floated a form of compatibilism before (i.e., our behaviors are subject to natural laws and that’s all; we can’t have done otherwise by volition at any given moment, but we still have free will), this time he appears to be a rock-hard determinist, which I like because I’m one, too. Excerpt from the interview are indented:
What’s more, beyond thoughts of death, my colleagues, according to Greene, are mistaken in their belief they are making their own choices to change their lives. Thoughts and actions, he argues, are interactions between elementary particles, which are bound by the immutable laws of mathematics. In other words, your particles are doing their thing; we are merely followers.
“I am a firm believer,” he says, “that we are nothing but physical objects with a high degree of order [remember these words, “high degree of order” – we’ll circle back to that], allowing us to have behaviours that are quite wondrous, allowing us to think and feel and engage with the world. But our underlying ingredients – the particles themselves – are completely, and always, governed by the law of physics.”
“Free will is the sensation of making a choice. The sensation is real, but the choice seems illusory. Laws of physics determine the future.”
So then, free will does not stand up against our understanding of how the universe works.
“I don’t even know what it would mean to have free will,” he adds, “We would have to somehow intercede in the laws of physics to affect the motion of our particles. And I don’t know by what force we would possibly be able to do that.”
Do you and I have no more options than say, a fish, in how we respond to the world around us?
“Yes and no,” says Greene. “All living systems, us included, are governed by the laws of physics, but the ways in which our collection of particles can respond to stimuli is much richer. The spectrum of behaviours that our organised structure allows us to engage in is broader than the spectrumof behaviours than a fish or a fly might engage in.”
He’s right, and there’s no attempt, at least in this interview, to be compatibilistic and say, well, we have a form of free will worth wanting.
Death: From the interview:
“People typically want to brush it off, and say, ‘I don’t dwell on dying, I don’t think about it,”‘ says Greene via Zoom from his home in New York, where he is a professor at Columbia University. “And the fact that we can brush it off speaks to the power of the culture we have created to allow us to triumph over the inevitable. We need to have some means by which we don’t crumble under the weight of knowing that we are mortal.”
. . . Greene believes it is this innate fear of death twinned with our mathematically marching particles that is driving my colleagues to new horizons, and driving my decision to write this story, and your choice to read it, all bolstered by Charles Darwin’s theory of evolution.
Greene’s view appears to be that a substantial portion of human behavior is driven by a combination of two things: the “naturalism” that deprives us of free will, combined with our learned (or inborn) knowledge and fear of death. The death part is apparently what, still without our volition, forces us into action. I’m not sure why that’s true, as the explanation’s not in the interview but perhaps it’s in the book. After all, some people argue that if you’re a determinist doomed to eternal extinction, why not just stay in bed all day? Why do anything? If we do things that don’t enhance our reproduction, it’s because we have big brains and need to exercise and challenge them. Yes, we know we’re mortal, but I’m not sure why this makes me write this website, write books, read, or do science. I do these things because they bring me pleasure. What does mortality have to do with it?
Natural selection: According to the writer and interviewer Jeff Allen (an art director), Greene thinks that the promulgation of our mortality, as well as much of our communication, comes from storytelling, which has been instilled into our species by natural selection. Things get a bit gnarly here as the interview becomes a bit hard to follow. I’m sure Greene understands natural selection better than Allen, but Greene’s views are filtered through the art director:
Natural selection is well known for driving physical adaptation, yet it also drives behavioural change, including complex human behaviours such as language and even storytelling. Language is a beneficial attribute that helps us as a species succeed, as is the ability to tell stories, which prepare the inexperienced with scenarios that may benefit them in the future.
“Evolution works by tiny differentials in adaptive fitness, over the course of long timescales. That’s all it takes for these behaviours to become entrenched,” says Greene. “Storytelling is like a flight simulator, that safely allows us to prepare ourselves for various challenges we will face in the real world. If we fail in the simulator, we won’t die.”
Darwin’s theory of evolution is one of the recurring themes of Greene’s book.
Note in the first paragraph that evolved language and storytelling “helps us as a species succeed”. That’s undoubtedly true—though I’m yet to be convinced that storytelling is anything more than an epiphenomenon of evolved language—but whatever evolved here was undoubtedly via individual (genic) selection and not species selection. Traits don’t evolve to enable a species to succeed; they evolve (via selection) because they give their bearers a reproductive advantage. I’m sure Greene knows this, but Allen balls things up by throwing in “species success”.
Consciousness: If you’re tackling the Big Issues that deal with both philosophy and science, it’s consciousness, defined by Greene (and I) as both self-awareness and the presence of qualia, or subjective sensations (Greene calls it “inner experience”). I’ve written about this a lot, and don’t propose to do more here. We have consciousness, we don’t know how it works, but it’s certainly a physical property of our brains and bodies that can be manipulated by physical interventions. The two issues bearing on Greene’s piece are where it came from and how will we figure out how it works. (Greene implicitly rejects panpsychism by asking “”How can particles that in themselves do not have any awareness, yield this seemingly new quality?”. That will anger Philip Goff and his coterie of panpsychists.)
I’m not sure about the answer to either., We may never know whether consciousness is an epiphenomenon of having a big brain or is partly the result of natural selection promoting the evolution of consciousness. I suspect it’s partly the latter, since many of our “qualia” are adaptive. Feeling pain is an aversive response that protects us from bodily damage; people who lack the ability to feel pain usually accumulate substantial injuries. And many things that give us pleasure, like orgasms, do so because they enhance our reproduction. But this is just speculation.
Greene also thinks that natural selection has something to do with human consciousness, but it’s not clear from the following whether he sees consciousness as an epiphenomenon of our big brain and its naturalistic physical properties, or whether those properties were molded by natural selection because consciousness enhanced our reproduction:
“My gut feeling,” says Greene, “Is that the final answer will be the Darwinian story. Where collections of particles come together in a certain kind of organised high order ‘brain’, that brain is able to have particle motions that yield self-awareness. But it’s still a puzzle at this moment.”
Where Green and I differ is in what kind of work might yield the answer to how consciousness comes about. Greene thinks it will come from work on AI, while I think it will come, if it ever does, from neurological manipulations. Greene:
“That’s perhaps the deepest puzzle we face,” says Greene. “How can particles that in themselves do not have any awareness, yield this seemingly new quality? Where does inner experience come from?”
Greene’s suspicion is that this problem will go away once we start to build artificial systems, that can convincingly claim to have inner awareness. “We will come to a place where we realise that when you have this kind of organisation, awareness simply arises.”
In June this year, Google engineer Blake Lemoine said an AI he was working on, named LaMDA (Language Models for Dialogue Applications), got very chatty and even argued back.
I suppose this is a version of the Turing test, but it will be very, very hard to determine if an AI bot has “inner awareness”. Hell, I don’t even know if my friends are conscious, since it depends on self-report! Can you believe any machine that says it has “inner experiences”?
With that speculation I’ll move on. Greene also muses on the origin and fate of the universe, and whether it might “restart” after it collapses, but cosmology is above my pay grade, and I’ll leave you to read about that yourself.
I’m sure this topic has been covered by scientists before, but I haven’t researched it, so I’m raising it as a naive question.
First, it’s easy for you to tell up from down because down is where your feet are and up is what you see when you look away from your feet and toward the sky. Or you could drop something; the direction it falls is “down”.
It’s also easy for you to tell your front from your back. Your front is what you see when you look down, and the other side of your body is your back.
But how do you tell right from left at any given moment?
Now of course there are a number of cues that we could use to tell right from left. The side our heartbeat is most detectable by touch is on the left (unless you have situs inversus!), I wear my watch on my left wrist and my ring on my right hand, and so on. If you drive a car in the US, the steering wheel is on the left side.
But we don’t actually use these cues. When someone tells you “turn right” when you’re asking directions, you just know which way to go. But HOW?
Presumably we learn right from left when we’re kids: a parent presumably points out your right hand and says “that’s the right hand” and vice versa. But again, what cues do we use now? Surely not the hands! (I’m sure the answer is out there somewhere, but if a reader provides it, many of us will have learned something.)
That’s my question, but it’s related to a genetics question that I pondered for years before any answer was ever given. It’s about asymmetry in animals. There are basically two types of ways a bilaterally symmetrical animal can be asymmetrical in some ways. I’ve posted on this three times before (here ,here, and here), so have a look at those posts. Here’s just a brief summary.
1.) Fluctuating asymmetry. Individuals are asymmetrical for some features, but the direction of asymmetry varies from individual to individual. Handedness in humans is this way, though it has a genetic component, too, making right-handed people more common. Lobsters have asymmetrical claws: one is a “cutter” and the other a “crusher”, and it’s random whether the crusher claw is on the right or left. (We know, by the way, how this comes about. Young lobsters start their lives with identical claws, but the claw that is used most often provides more neurological activity, and that activity irrevocably creates the asymmetry, which lasts for life.The most-used one becomes the grinder.) Some species of flounders are randomly flat on the left or right sides, though all start off being vertically postured fish who develop into flat fish, with the eye on the bottom migrating to the top. Many human facial features are examples of fluctuating asymmetry: the right sides of our faces are not the same as the left, but the kind of differences differ in direction from person to person. Fluctuating asymmetry is also called “anti-symmetry” since the sides are different, but not in a consistent direction.
2.) Directional asymmetry. This is what always puzzled me. There are some basically bilaterally symmetric animals, like us, in which there are some asymmetries that are directional. That is, the right side always differs from the left in a consistent way. The narwhal tusk (a hyper-developed canine tooth) is always on the left side, some owls use directionally asymmetrical ears as a way to locate prey, I’ve mentioned the human heart before, and there are many examples. (In some flounder species, individuals are always right-flat, while individuals of other species are left-flat.)
The question I always had about this rests on the observation that because every individual is directionally asymmetrical the same way, that asymmetry must somehow rest on genes for those traits that are active in development. But how does a gene know it’s on the right or left side so it can turn on or off? Given a bilaterally symmetrical individual, it’s easy to genetically specify “front” and “back”, and “up and down”, but once those are specified, then the internal features of the organism should be identical on the right and left side. So how does a gene for say, hyper-development of the canine tooth “know” that it’s on the left side to become activated? There has to be some consistent physiological or metabolic difference between the right and left sides of an animal to provide the relevant developmental cues. But how could that occur?
We’re beginning to find out now, though we’re far from a complete understanding of the phenomenon. There are two suggestions I know of, based on either the asymmetry in the way embryonic cilia beat (causing an asymmetry in the flow of embryonic fluid) or in the “handedness” of our constituent amino acids. I describe these in the second post I wrote in the series.
Of course, once a single directional asymmetry has evolved in an animal or plant, then the evolution of further directional asymmetries can evolve using developmental cues provided by the first one.
But this is irrelevant to the question above, so I repeat it:
How do you know the difference between left and right?
I’m sure that historians have pondered the first question at length, but I haven’t read their lucubrations. According to Wikipedia, the first definitive use of the wheel on transportation was in Mesopotamia around 3500 B.C. We don’t know how many times it was invented independently, but probably more than once (see below):
So, my first question is this: Why was the wheel not devised in the New World? The Americas had plenty of civilizations, including many Native American groups, and the Aztecs, Incas, and Maya as well as many other groups, but none of them had the wheel, with one exception (see below). Why? Further, the Diquis culture had stone spheres beginning about 300 A.D., so they certainly knew that something round could roll. But this wasn’t adapted for carts or other rolling entities. Yet the Incas are said to have used wooden rollers to roll large stones for their walls and cities. Why no wheels, then?
The wheel evidently was familiar to the ancient Mexicans, the only known instance of its having been invented independently of the Sumerian version. Unfortunately, it apparently never occurred to anyone at the time that wheels had any practical application, and their use was confined to little clay gadgets that are thought to be either toys or cult objects.
That link also gives you an explanation that Cecil Adams considers definitive, but I don’t know. See for yourself. I am guessing that Jared Diamond pondered this question in Guns, Germs, and Steel but I read it so long ago I can’t recall. Go to the link, read “the” answer to my question above, and see if you agree with Cecil.
My second question is this: How did our ancestors keep their fingernails and toenails at reasonable length?
I thought of this question while clipping my nails the other day, and thought, “Scissors and nail clippers, and even steel knives were not invented in fairly late in human history. But yet our ancestors did without them for millions of years. How did they keep their nails short?
Now you might say, “They didn’t need to: their nails wore down from hunting, gathering, and walking barefoot.” But I am not sure this is the case. How would walking barefoot wear down your toenails? And we know that, at least in modern society, if you don’t trim your fingernails and toenails, they get ungodly long (see below). Did the ancients use flint? And what did they do before they had flint implements? Or did they bite their fingernails?
Now we could surely answer this question by observing what hunter-gatherers do, if anything, to keep their nails short. But I am not going to look it up; I’d rather have readers speculate or, if they know the answer, tell me.
Below: a video showing what happens if you don’t trim your nails: here’s a man who didn’t trim the nails on one hand for 66 years. (He explains why.) He has, on that hand, the longest known fingernails in history.
Of course he had to cut his nails on his right hand so he could do stuff (and I’m betting he’s a rightie). Nobody would marry him, and you can imagine the trouble he had just living from day to day. It’s all in the video
In the early days of evolutionary psychology—that is, when it was just beginning to be applied to humans—I was rather critical of the endeavor, though not so much about “sociobiology”, the application of evolutionary principles to animal behavior. A lot of the early evo psych stuff on humans was weak or overly speculative.
Since then, I’ve mellowed somewhat in light of replicated research findings about human behavior that show phenomena predicted by or very consistent with the theory of evolution. Not only are the phenomena predicted and replicated, but they are in line with what other animals show. Further, researchers have also falsified some alternative explanations (“culture” or “patriarchy” is the most common one).
I’ll add here that the disturbingly common claim that evolutionary psychology is “bogus” or “worthless” as an entire field is ridiculous, both in principle and in practice. In principle, why should human behavior, or behavioral differences between the sexes, be the one area that is exempt from evolutionary influence, especially given that we evolved in small hunger-gatherer groups for at least five million years, on top of which is overlaid a thin veneer (about 20,000 years) of modern culture? That position—that all differences between men and women, say, are due to cultural influence—is an ideological and not an empirical view. If physical differences, both between sexes and among groups, are the result of evolution, why not mental ones? After all, our brain is made of cells just like our bodies!
In practice, there are several types of human behavior that, using my mental Bayes assessment, I consider likely to reflect at least some of the workings of evolution, past and present, although culture may play a role as well. There will be an upcoming paper on these fairly solid evo-psych behaviors (I’m not an author), but I’ll highlight it when it’s published.
In the meantime, we have one behavior, described in this 2017 article from Areo Magazine, that describes a “universal human behavior” involving sex differences, and a behavior that’s likely to reflect our evolutionary heritage. Although the article is four years old, it’s worth reading. The author, David P. Schmitt, has these bona fides:
David P. Schmitt, PhD, is Founding Director of the International Sexuality Description Project, a cross-cultural research collaboration involving 100s of psychologists from around the world who seek to understand how culture, personality, and gender combine to influence sexual attitudes and behaviors.
See also his Wikipedia page, which describes him as “a personality psychologist who founded the International Sexuality Description Project (ISDP). The ISDP is the largest-ever cross-cultural research study on sex and personality.”
The article, which I recommend you read, is chock-full of data. Click on the screenshot for a free read:
The behaviors Schmitt discusses in this longish but fascinating and readable piece are summarized in the first two paragraphs (there are lots of references should you want to check his claims):
Choosing to have sex with a total stranger is not something everyone would do. It probably takes a certain type of person. Quite a bit of evidence suggests, at least when it comes to eagerly having sex with strangers, it might also take being a man. Let’s look at the evidence.
Over the last few decades almost all research studies have found that men are much more eager for casual sex than women are (Oliver & Hyde, 1993; Petersen & Hyde, 2010). This is especially true when it comes to desires for short-term mating with many different sexual partners (Schmitt et al., 2003), and is even more true for wanting to have sex with complete and total strangers (Tappé et al., 2013).
Of course this is “common wisdom” in American culture: it is the heterosexual guy who does the pursuing, and does so without many criteria beyond the lust object having two X chromosomes, and he’s still often rejected, while women are far choosier about who they mate with.
There are many studies, described and cited by Schmitt (usually using lab experiments or good-looking students on campus approaching members of the opposite sex) that show the same thing. An attractive man propositioning a woman for sex is accepted about 0% of the time, while, in the opposite situation far more than half the males accept a sexual proposition from an attractive female stranger. Here are two studies, but there are more:
In a classic social psychological experiment from the 1980s, Clark and Hatfield (1989) put the idea of there being sex differences in consenting to sex with strangers to a real life test. They had experimental confederates approach college students across various campuses and ask “I’ve been noticing you around campus, I find you to be very attractive, would you go to bed with me tonight?” Around 75 percent of men agreed to have sex with a complete stranger, whereas no women (0 percent) agreed to sex with a complete stranger. In terms of effect size, this is one of the largest sex differences ever discovered in psychological science (Hyde, 2005).
Twenty years later, Hald and Høgh-Olesen (2010) largely replicated these findings in Denmark, with 59 percent of single men and 0 percent of single women agreeing to a stranger’s proposition, “Would you go to bed with me?” Interestingly, they also asked participants who were already in relationships, finding 18 percent of men and 4 percent of women currently in a relationship responded positively to the request.
This of course jibes with the behavior of many animals (in my flies, for example, males will court almost any female, even wooing pieces of dust or small blobs of wax), while females repeatedly reject males. It’s true of primates in general, and of many animal species. And it makes evolutionary sense. If a male mates with five females instead of one, he’s likely to have five times more offspring. In the reverse situation, though, a female who mates with five males in a short period will have roughly the same number of offspring as if she mated just once. That’s because she makes a huge investment in eggs and (in some species like ducks) maternal care, and so she should be selected to be choosy about her mates, looking for a male who is fit, healthy, may have good genes, and, if there’s parental care, will be an attentive father. Since the male has far less to lose, and far more to gain, by repeatedly mating with different females, this explains the strategy of “wanton male versus choosy female” sexual preference. These are likely to be evolved sexual behaviors.
This of course is a generalization. There are certainly picky men and women who are less choosy about their partners. But it’s a generalization that holds up not only in the “choice” studies I just mentioned, but in other aspects as well. Psychological studies show that (here I quote Schmitt, bolding is his)
. . . men have more positive attitudes towards casual sex than women, have more unrestricted sociosexuality than women, and generally relax their preferences in short-term mating contexts (whereas women increase selectivity, especially for sexual attractiveness.
. . . Cognitively and emotionally, men are more likely than women to have sexual fantasies involving short-term sex and multiple opposite-sex partners, men perceive more sexual interest from strangers than women, and men are less likely than women to regret short-term sex or “hook-ups.”
Considering sexual fantasies, men are much more likely than women to report having imagined sex with more than 1,000 partners in their lifetime (Ellis & Symons, 1990).
Behaviorally, men are more likely than women to be willing to pay for short-term sex with (male or female) prostitutes, men are more likely than women to enjoy sexual magazines and videos containing themes of short-term sex and sex with multiple partners, men are more likely than women to actually engage in extradyadic sex, men are more likely than women to be sexually unfaithful multiple times with different sexual partners, men are more likely than women to seek one-night stands, and men are quicker than women to consent to having sex after a very brief period of time (for citations, see Buss & Schmitt, 2011).
Here’s a table reproduced in the Areo paper taken from Buss and Schmitt (2011), where you can find the original references. Click to enlarge.
These patterns hold in nearly all studies in different parts of the world. That in itself suggests that culture may play an insignificant role in the difference I’m discussing.
Now if you’re thinking hard, you can think of at least four non-evolutionary explanations for these behaviors (I’ve combined disease and pregnancy in #3 below). Both, however, have been shown to be unlikely to be the major explanation for the sex difference in choosiness.
1.) Patriarchy: These could be cultural differences enforced by the patriarchy and socialization. Why a patriarchy exists itself may be evolutionary (e.g., males are stronger and thus can control females more easily than the other way around), but male dominance itself is not the explanation we’re testing here. Schmitt explains why (beyond observed cultural universalism), this is unlikely to explain the entire behavioral difference (all emphases are the author’s):
For instance, Schmitt (2015) found sex differences in the sociosexuality scale item “I can imagine myself being comfortable and enjoying ‘casual’ sex with different partners” were largest in nations with most egalitariansex role socialization and greatest sociopolitical gender equity (i.e., least patriarchy, such as in Scandinavia). This is exactly the opposite of what we would expect if patriarchy and sex role socialization are the prime culprits behind sex differences in consenting to sex with strangers.
How can this be? Why are these sex differences larger in gender egalitarian Scandinavian nations? According to Sexual Strategies Theory (Buss & Schmitt 1993), among those who pursue a short-term sexual strategy, men are expected to seek larger numbers of partners than women (Schmitt et al., 2003). When women engage in short-term mating, they are expected to be more selective than men, particularly over genetic quality (Thornhill & Gangestad, 2008). As a result, when more egalitarian sex role socialization and greater sociopolitical gender equity “set free” or release men’s and women’s mating psychologies (which gendered freedom tends to do), the specific item “I enjoy casual sex with different partners” taps the release of men’s short-term mating psychology much more than it does women’s. Hence, sex differences on “I enjoy casual sex with different partners” are largest in the most gender egalitarian nations.
Overall, when looking across cultures, reducing patriarchy doesn’t make these and most other psychological sex differences go away, it makes them larger (Schmitt, 2015). So much for blaming patriarchy and sex role socialization.
2.) Fear of injury. In general, men are stronger than women (this is almost surely the result of evolution affecting competition for mates). Perhaps women are leary of accepting propositions from unknown men because they might get hurt, as do many prostitutes. But several studies show that safety alone cannot be the whole explanation:
Clark (1990) was among the first to address the issue of physical safety. He had college-aged confederates call up a personal friend on the phone and say “I have a good friend, whom I have known since childhood, coming to Tallahassee. Joan/John is a warm, sincere, trustworthy, and attractive person. Everybody likes Joan/John. About four months ago Joan/John’s five year relationship with her/his high school sweetheart dissolved. She/he is was quite depressed for several months, but during the least month Joan/John has been going out and having fun again. I promised Joan/John that she/he would have a good time here, because I have a friend who would readily like her/him. You two are just made for each other. Besides she/he has a reputation as being a fantastic lover. Would you be willing to go to bed with her/him?” Again, many more men (50%) than women (5%) were willing to have sex with a personally “vouched for” stranger. When asked, not one of the 95% of women who declined sex reported physical safety concerns were a reason why.
3.) Fear of pregnancy and/or disease. Since venereal diseases can be passed in both directions, I’m not sure that disease is a good explanation, though perhaps women are more likely to get serious disease than are men. As far as pregnancy is concerned, there’s at least one study showing it can’t be the sole factor:
Surbey and Conohan (2000) wondered whether worries of safety, pregnancy, stigma, or disease were what was holding women back from saying yes to sex with a stranger. In a “safe sex” experimental condition, they asked people “If the opportunity presented itself to have sexual intercourse with an anonymous member of the opposite sex who was as physically attractive as yourself but no more so (and who you overheard a friend describe as being a well-liked and trusted individual who would never hurt a fly), do you think that if there was no chance of forming a more durable relationship, and no risk of pregnancy, discovery, or disease, that you would do so?” On a scale of 1 (certainly not) to 4 (certainly would), very large sex differences still persisted with women (about 2.1) being much less likely to agree with a “safe sex” experience with a stranger compared to men (about 2.9).
So, sex differences in agreeing to sex with strangers are not just a matter of safety issues, pregnancy concerns, slut-shaming stigma, or disease avoidance. Controlling for all of that, researchers still find large sex differences in willingness to have sex with a stranger.
There’s a lot more in this paper, including Schmitt’s critique of the two papers cited widely as disproving the “pickiness” hypothesis. Both papers, however, suffer from extreme methodological flaws, and in both cases the results support the “pickiness” hypothesis when the flaws are corrected.
You can read the hypothesis and judge for yourselves, but I think this is one of the best examples we have of evolutionary psychology explaining a difference between men and women in behavior*. As I said, it’s shown up throughout the world in different cultures, it’s paralleled in many species of animals, alternative explanations fail to explain the data, other, unrelated data support at least a partial evolutionary basis of the choice difference, and the few papers that claim to disprove it wind up actually supporting it.
Aside from “universal” behavior like sleeping, eating, or wanting to reproduce, which are surely instilled in us by evolution (and nobody questions those), we shouldn’t ignore differences between groups, especially the sexes, as having an evolutionary origin. It’s likely that morphological differences between geographic populations, like the amount of melanin in the skin, are adaptive responses to natural selection, so why is behavior the one trait that is always off limits to evolutionary explanation? It’s ideology, Jake.
h/t: Steve Stewart-Williams
*As a reader points out below, and even more obvious evolutionary difference is that the vast majority of men are sexually attracted to women, and vice versa. That would be hard to explain as a result of the patriarchy or of socialization.
A while back, someone gave me a Chinese backscratcher: a piece of bamboo with a hand carved at the end with slightly separated fingers. I use it every couple of days when my back works up a good itch, and believe me, it provides substantial relief! Here’s what mine looks like:
But when I use it I’ve pondered two questions.
A.)Is the relief you get when scratching your back pleasure, or simply the removal of discomfort? (Or are they equivalent?) This same question applies when you finally make it to the restroom after having to hold your bowels or bladder for a long time. I wonder if philosophers have debated this question.
B.) Why do backs itch so much? I have two theories here, which are mine. The first is that they itch no more than do fronts (i.e., your chest), but we’re unconsciously scratching our fronts all the time, while we can’t reach our backs without a special implement. But I don’t notice myself scratching my chest.
The other is that dirt and oils accumulate on your back more than they do on your front, simply because you can’t reach your back so easily in the bath or shower. I don’t have a sponge on a stick or anything like that, and so am forced to wash my back by reaching around with a piece of soap. I’m never sure that does a great job because it’s hard to reach all the places. If any accumulated back schmutz makes you itch, this could be an explanation.
Maybe there are other theories as well, but these are the only two I’ve thought of.
Reader Bryan sent me a link to this video by Steve Mould discussing how our ability to rotate our eyes may be an exaptation (and a vestigial remnant) from ancestors who had eyes on the sides of their head. It’s a fascinating idea, and may well be true. Or, to quote the YouTube notes:
Torsional eye movement, known as cycloversion and cyclovergence have a fascinating evolutionary history via our evolutionary ancestors that had eyes on the sides of their heads. Your eyes twist in this way whenever you tilt your head!
After 10:07 there are ads, so you may wish to skip the last two minutes of the video.
This new paper in Nature (click on screenshot, pdf here, reference at bottom) has the potential to be the big human-paleobiology story of the last several years. It reports finding human occupancy of a high-altitude cave in Mexico during the last glacial maximum (LGM): about 26,000 years ago. And that, say the authors, implies that humans have been in the New World since more than 30,000 years ago—more than doubling the time we thought they’d been here. Previously, the best guess was that humans crossed the Bering Strait from Siberia about 15,000 years ago, and then spread through the Americas.
Click on the screenshot below to get the paper (free through the legal app Unpaywall, or you can make a judicious inquiry).
Before we accept these results as overturning the received wisdom about humans in the New World, though, there has been some criticism of the paper, as you can see in a precis in Science by Andrew Curry.
The cave where the finds were made sits atoop a remote mountain in the Mexican state of Zacatecas, about 2,740 m high, and has been studied since 2012. Although dry and barren now, it was thought to be verdant during the LGM, with water, plants, and plenty of edible animals nearby. Researchers worked there for a month at a time, camping in the cave and hauling water and food by donkey from the nearest town.
What made the researchers suppose that the cave was occupied by humans were several things, most prominently 2000 specimens of what looked like sculpted tools. Here’s a figure showing some of these putatively manufactured objects:
Now I would have thought that by now paleoanthropologists would be able to distinguish non-human rock artifacts from real, chipped tools, but apparently that’s not the case. As one critic says in the Science writeup:
Critics point out that the tools are simple and don’t resemble other toolkits from the Americas, raising the possibility they’re the product of natural breakage. “They look like they could be artifacts, but why aren’t they found anywhere else in the landscape?” wonders David Meltzer, an archaeologist at Southern Methodist University. The tools’ consistency is also remarkable, he says. “If these tools are real, why are they only found—so far at least—in this one spot over a 10,000-year period? Humans adapt and adopt new technology.”
The tool-making conclusion, at least, must remain tentative. There was also burned wood that was radiocarbon dated, implying human campfires, but the critics again say that this could derive be from “wind-blown” wildfires. The researchers also used OSL dating of quartz from the sediments, which tells you when the mineral was last exposed to light, ergo when it was laid down.
Finally, the researchers trawled the cave for DNA, which they could sequence to see what kind of animals and plants were there. The fauna included bats, mice and other rodents, marmots, goats, and sheep, as well as birds, though this could have come from more recent occupancy. Plant DNA included forest species like spruce, pines, grasses, and palms. The disappearance of cold-adapted species and forest trees that gave way later to Joshua trees and grasses suggests that the sediments in the cave did go through the late Glacial Maximum, which was followed by a period of dryness.
Notably, no human or humanoid DNA was found in the cave, which would have gotten people much more excited about this find.
How strong is the evidence for human presence in the Americas beginning 30,000 years ago? The 30,000 years is a guess by the authors, derived from guessing how long it would take humans to get to a 26,000-year-old cave residence in Mexico after crossing from Siberia. In terms of the age of the cave itself, that seems reasonable, but the evidence for human occupation is largely the “tools”, and their provenance is doubtful. And if humans inhabited the cave continuously for millennia, as the authors suppose, then why wasn’t human DNA found there? My judgment, and I’m a tyro here, is that the evidence is intriguing but not terribly strong. A lot hinges on whether the “tool-like” stone artifacts really were chipped by hominin hands.
On the other hand, the Science article says that there is a cave in the Yukon that’s yielded dates as old as the Mexican cave (about 24,000 years), but although it contains thousands of animal bones, there are “few stone tools or cut marks.” But other researchers are beginning to think that people came to America earlier than we thought, and could have spread quickly by traveling along the West coast by boat, avoiding the largely frozen interior. Here’s a tweet (h/t: Matthew) showing sites where there could have been earlier habitations:
News & Views: Two studies in Nature report evidence that the initial human settlement of the Americas happened earlier than is widely accepted. Some of the evidence suggests settlement began at least 10,000 years earlier than was generally suspected. https://t.co/OBuIQzBI7v
How good are the dating methods? From what I read, they seem fairly reasonable, and they used at least two methods that give about the same dates. The question is not how old the cave is, but whether humans lived there and made the tools and charcoal.
What happened to the people? Part of the reason we think humans have been in the New World for only 15,000 years is not just evidence from habitation, but from DNA of Native Americans (note: there are some older estimates). If that’s the case, why doesn’t the DNA give a consistent age of 30,000 years from when Native Americans branches off from East Asians? One possibility is that the early arrivers went extinct without leaving descendants, so we wouldn’t find a genetic signature of their existence. Given that some paleoanthropologists see evidence of an early arrival from other sites, like that in the Yukon, the possibility of extinction seems unlikely.
All in all, this is an exciting finding, and may well be right, but we’ll have to let the experts fight it out.
Excavating in the cave, a photo from the Science precis:
Yesterday I wrote about Angela Saini’s misguided claim that human populations and races (I prefer “ethnic groups” rather than “races”) are basically genetically identical. So identical, in fact, that, as Saini argued, it’s entirely possible (or even likely) that the genomes of a South Asian and a white Canadian could be more similar than the genomes of two South Asians. That is wrong, but plays into Saini’s ideological bias that there are no appreciable or meaningful difference between biological races.
As I indicated, we now have sufficient data to show that the chances that her assertion is true is close to zero. Looking at the whole genome, you’re not going to find many South Indians whose DNA is more similar to that of a white Canadian than to that of another South Asian.
In trying to understand why Saini would make such a statement, I speculated that she had bought into the “Lewontin fallacy“: the claim by my ex Ph.D. advisor that the vast bulk of genetic variation segregating in our species occurs among individuals within populations, rather than among populations within a classically-defined “race” or among races.
From his mathematical analysis, Lewontin concluded that the term “race” has no biological reality. The error of Lewontin’s claim was pointed out by geneticist A.W.F. Edwards, who noted that Lewontin was treating each gene as independent. But they’re not, because the constraints of history, geographic separation, and evolution ensures that differences among populations and races at different genes are correlated. Taking these correlations into account, Edwards concluded this (characterized in Wikipedia):
In Edwards’ words, “most of the information that distinguishes populations is hidden in the correlation structure of the data.” These relationships can be extracted using commonly used ordination and cluster analysis techniques. Edwards argued that, even if the probability of misclassifying an individual based on the frequency of alleles at a single locus is as high as 30 percent (as Lewontin reported in 1972), the misclassification probability becomes close to zero if enough loci are studied.
And the use of cluster analysis is in fact the way that population-genetic studies are able to describe evolutionary history and ancestry from DNA data. I cited cluster analysis of the genetic structure of the British Isles as an example of how well one can deduce someone’s ancestry and geographic origin from looking at half a million base pairs—a small fraction of the total DNA in the human genome (about 0.02%).
I stand by my claim that Saini was wrong, but I did err on one count, one that doesn’t affect my conclusions but that I wanted to point out to be scientifically accurate.
And that is this: Lewontin’s original claim about the apportionment of genetic variation among individuals, populations, and races was incorrect. This was pointed out to me by reader, biologist, and polymath Lou Jost, who works at a field station in Ecuador. I vaguely remembered that Lou had done some work on this, but had forgotten, as he just reminded me, that work completely invalidates Lewontin’s method.
Lou has written several papers on this error, one of which you can access for free. (I have the other papers if you want the pdfs.) Click on the screenshot:
The math behind Lou’s arguments is above the pay grade of many of us (including me), but I, at least, am convinced that Lewontin was wrong for reasons beyond Edwards’s claim: he was wrong because, as Lou showed, he “used a measure of ‘differentiation’ that doesn’t really measure differentiation.” Lou presented an alternative diversity-based model that will allow you to compare differentiation within and among groups (this holds for species diversity in ecology as well as genetic diversity in and among populations), but he didn’t apply it to Lewontin’s data, because those data are outmoded now (they were based on electrophoretically derived allele frequencies).
The take-home lesson is that Lewontin’s conclusion is wrong not only because it applies to single loci assumed to be uncorrelated, but also because he used the wrong metric to compare within- versus between-group diversity. As Lou noted, the take-home lesson of Lewontin’s paper—that most of the genetic diversity in our species is present in any population of our species, with only smaller amounts added by looking at different populations or races—may still be right. But until Lou’s metrics are applied to the new and better data we have, we just won’t know.
Again, this correction affects an idea that I thought Saini might have been erroneously pondering when she made her misleading statement. It does not affect the fact that her statement is misleading, and that we really can distinguish populations and ethnic groups very well using genetic data—the more data the better. And it doesn’t affect my claim that Saini is either deliberately misleading people or is ignorant about the data on population differentiation in our species, and that her ignorance, willful or not, plays into her ideological narrative about “races.”
I stand corrected on the Lewontin issue, and thank to Lou Jost for setting me straight about the “Lewontin fallacy.”