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.
Here from Science Advancesvia National Geographic, is the painting of a wild pig from the Indonesian island of Sulawesi. AT 45,000 years old, it’s world’s oldest cave art, and in fact the oldest known representational art of any sort.
Here’s the paper reporting it (click on screenshot), and a free pdf is here:
The very oldest art comes not from Europe or Africa, but from Indonesia; but surely there was much earlier representational art. The subject is presumably a Celebes warty pig (Sus celebensis), a species still with us, and the artist presumably an anatomically modern human (H. sapiens sapiens).
Here’s the subject. Not a bad representation, eh?
And a few words from the authors (“AMH” means “anatomically modern humans”)
On the basis of the presently available evidence, we are unable to definitively conclude that the dated figurative rock art depiction from Leang Tedongnge is the handiwork of cognitively “modern” members of our species. However, this seems to be the most likely explanation given the sophistication of this early representational artwork and the fact that figurative depiction has so far only been attributed to AMH everywhere else in the world.
If so, the dated pig image from Leang Tedongnge would appear to provide some of the earliest evidence, if not the earliest, for the presence of our species in Wallacea. The minimum age of this artwork is compatible with the earliest established indications of AMH from excavated deposits in the Lesser Sunda islands, which formerly provided the oldest archaeological evidence for H. sapiens in Wallacea (~44.6 ka cal BP). Hence, dating results for the Leang Tedongnge painting underline the view that representational art, including figurative animal art and depictions of narrative scenes, was a key part of the cultural repertoire of the first AMH populations to cross from Sunda into Wallacea—the gateway to the continent of Australia.
Since I’m including Homo sapiens as “wildlife” now (we are a species on the planet), I will accept good photos of human beings in this feature. After seeing the excellent people photos of Joe Routon, Joe Dickinson submitted his own collection. Joe D.’s captions are indented:
This and several following photos are from a trip to India about seven years ago, guided by my sister-in-law who had spent a year there as a youngster when my father-in-law was setting up the first computer center in India. (My wife and I “house sat” for their home in Berkeley for the first year of our marriage.) She (my sister-in-law) returned to India for at least a year on two occasions, teaching at a well-known school for international students. I visited her there when attending an International Congress of Genetics (1972?) in Delhi . [JAC: I was at that Congress too, but I think it was after 1972.]
Here is the happy couple from a wedding taking place at the hotel we were staying in.
Some young Muslim women in a market.
Now we jump back to Africa, near Lake Victoria.
Some ladies demonstrating spinning and weaving methods in the Chilean Andes.
And me, back in the boat after some snorkeling in French Polynesia.
A new report in Nature displays what is said to be the oldest “figurative artwork” in the world—work that is representational of real-world items rather than just abstract figures. It shows not only hunting scenes, but “therianthropes” (human-animal hybrid figures), and also is the oldest “narrative art”, as it’s said to depict a hunting scene. (Click on screenshot below to read the article, and you can find the pdf here). How old is it? Uranium/thorium dating places a minimum age of the cave paintings at 43,900 years, making it older than the oldest nonrepresentational art: a disk dated at 40,800 years from Spain.
The authors start the paper with a history of “oldest” art, which I’ll reproduce below (I have photos of the stuff that I’ve put in bold):
Previous uranium-series (U-series) dating has suggested that the oldest known figurative cave art is found in Indonesia. Up until now, the earliest minimum U-series ages for representative artworks reflect dates of 40 ka for a naturalistic painting of a wild bovid in Kalimantan and, from south Sulawesi, 35.4 ka for a painting of a pig—possibly a female babirusa or young Sulawesi warty pig (Sus celebensis). Non-figurative rock art dated to 65 ka in Spain has been attributed to Neanderthals, but this claim has been questioned on various grounds. With a minimum age of 40.8 ka, the earliest dated art that is generally attributed to modern humans in Europe is an abstract ‘disc’ sign from the rock art site of El Castillo in Spain. Although animal motifs are abundant in the Pleistocene cave art of Indonesia and Europe, in both regions humans hunting fauna are very seldom depicted; composite human–animal figures are also uncommon. In Europe, images of lone animals that are seemingly impaled by projectiles are documented in art of Magdalenian cultures (dating to about 21–14 ka); however, the motifs that are regarded by some as spears or arrows are subject to varying interpretations In terms of parietal imagery, one of very few obvious narrative compositions is the famous scene from the shaft (or ‘well’) at Lascaux (France) (Extended Data Fig. 1). This Magdalenian rock art panel apparently depicts a bird-headed man being charged by a wounded bison. The shaft scene is the subject of considerable speculation, but some scholars believe it represents a real hunt; if this is the case, so far as we can ascertain this would be the oldest narrative composition that portrays a hunting scene in European art. The earliest image that is generally accepted to represent a therianthrope is the Löwenmensch (‘lion-man’) figurine, a 31.1-cm-tall mammoth-ivory statuette of an apparently part-human, part-lion creature from Hohlenstein–Stadel (Germany) (Extended Data Fig. 1). This artefact, which belongs to the early Aurignacian tradition (dating to about 40–39 ka), is regarded by some as the earliest evidence for the capacity to link the concepts of ‘animal’ and ‘person’ into a single abstract category. The Hohlenstein–Stadel figure also has a prominent role in scientific debates about the origins of religion, as it has been argued that the ability to imagine the existence of things that do not exist—including therianthropes—forms the basis for religious thought. In Kalimantan, U-series dating has shown that people began painting small anthropomorphic figures inside caves at least 14 ka, and perhaps as early as 21–20 ka—these figures are sometimes shown pursuing deer, but dates are not available for any of these scenes. To our knowledge, no unambiguous depictions of therianthropes have previously been identified in the early cave art of Kalimantan or Sulawesi.
Here are some pictures of the images put in bold in the text. First, the abstract disks at El Castillo, dated to at least 40,800 years and the oldest art of any kind. There are also handprints made by blowing pigment around a hand, which really conjures up our ancient relatives as people.
The 40,000 year old bovid figure from Borneo, previously the oldest figurative art:
And here, from the supplementary data in the new Nature paper, are several other pieces of artwork mentioned above, including the Lascaux cave painting, which shows the bird-headed man (all captions are from the Nature paper). The art at Lascaux is much younger: 21,000-14,000 years ago. You can also see the lion-man therianthope statue, which is about 39,000-40,000 years old, and is already quite sophisticated.
The new finds are from Sulawesi in Indonesia, with the location given below. The paintings are badly weathered (I presume they’ll find a way to protect them), but have also been marred by water seeping through the paintings and then mineralizing, forming calcium carbonate concretions called “coralloid speliotherms”, or “cave popcorn”. However, the fact that the paintings were later marred by mineral deposits also gives us a way to date them, since cave popcorn can be dated using decay rates of uranium into thorium.
So at last we get to the cave art in Sulawesi, which has been enhanced in the figure below, and then given representations in b). In c) and d) you can see enlargements showing what the authors take to be human/animal hybrids, and then a very large anoa, which is a midget buffalo found only on Sulawesi. I’ve put a picture of one species of anoa below the figure.
A lowland anoa (Bubalus depressicornis). There’s also a mountain anoa, and it’s not clear which species the painting above represents—or whether it’s a third species that’s now extinct. Both living species are endangered by hunting and habitat loss. These little creatures are only about a meter high at the shoulder.
The authors conclude that this is the world’s oldest known figurative art and also the oldest narrative art, which implies that humans were already engaged in storytelling 43,000 years ago. The authors consider storytelling important because “the ability to invent fictional stories may have been the last and most crucial stage in the evolutionary history of human language and the development of modern patterns of cognition.” Of course, they’re speculating here.
Finally, these are also the oldest therianthropes: almost twice as old as the Lacaux “birdman” and several millennia older than the lion-headed figure which held the previous record. At the end, of course, there’s the requisite speculation about spirituality, as the authors say the scene “hints at the deeply rooted symbolism of the human-animal bond and predator-prey relationships in the spiritual beliefs, narrative traditions, and image-making practices of our species.” Well, again that’s more speculation. But it does suggest that about 43,000 years ago, H. sapiens was already thinking in numinous terms, for what else would a therianthrope represent?
It would seem a no-brainer to say “I’m sorry” in a way that tells people—or lets them think!—that you’re sincere, but nobody seems to get it right these days. Last night, I heard the perpetrator of another blackface episode say, “I’m sorry that I offended people.”
Now that is not an apology, and it’s obvious why not. This person was sorry not for doing something racist, but for offending people. When I hear an apology like that, I think, “What this person is really sorry for is being caught.” An alternative interpretation is “I am sorry that you were offended, but maybe you shouldn’t have been.”
What really conveys sincerity is something like, “Yes, I behaved in a racist way. It was wrong, and I’m sorry for that. And I won’t do it again.”
Now of course many people who proffer “sincere” apologies, like the last one above, don’t really mean them. But humans being who we are, we’ll feel better hearing even insincere words that sound sincere. So be it. The ideal tactic, if you really have done something offensive, is to reflect on your behavior and, if you decide it was wrong, go tell the person/people you offended that you were wrong and that you’re sorry for what you did. (Even if you feel that you were partly right, swallow your pride and just apologize for the sake of comity.)
I don’t understand why people don’t grasp that it’s not enough to say that you’re sorry that people were offended. That conveys the idea that you regret that they became offended, not that you regret making them offended.
I don’t want to dwell too much on Ilhan Omar, who tendered the apology below when called out by senior Democrats in the House for her anti-semitic tweets, but this is not the way to apologize:
1.) It apologizes for offending people rather than for saying something anti-semitic. Does she think what she said was anti-semitic? I doubt it.
2.) She says her intention was not to be offensive. If not, what was it?
3.) She apologizes to a limited group of people: her constituents and Jewish Americans as a whole. Well, perhaps others, including Jews who weren’t Americans, were offended.
4.) She makes it about herself with the “I expect people to hear me when others attack me for my identity.” You don’t make excuses for saying what you said, or try to drag your own offense into an apology.
5.) The word “unequivocal” is defused by the fact that she equivocates in the rest of the apology.
6.) The stuff about the problematic nature of lobbyists completely ruins the apology, as it’s irrelevant and apparently is some sort of excuse for what she did. That again makes the apology “equivocal”, especially in view of Omar herself taking money from lobbyists. Why is it okay for her to take money from CAIR while others take money from NRA? (AIPAC does not give money to individual politicians, by the way)
A genuine apology—one without equivocation or excuses—goes a long way with other people. Just fricking say you were wrong and that you won’t behave that way again! It isn’t rocket science!