What the hell, Chad?

After Chad and Yara hit it off and mated, I started shuffling Chad off to meet other spider ladies. First up, I paired him with Melisandre.

This morning, I find one live spider and one dead spider. My immediate thought was that the little witch had murdered the male, but no — Chad was fine, it was Melisandre’s corpse that was dangling from a silken thread. This is not right. Chad, you brute. Now I hesitate to move a known domestic abuser to a new cage, the rotten killer. Mate, don’t murder.

I suppose it’s possible Melisandre lost her magic necklace and just died of old age…

You see a man with spiders in his beard: shag, marry, kill?

This story was making the rounds last week, about a study that had found that women who are creeped out by bugs are less likely to be attracted to men with beards.

According to a new study, if a woman runs screaming from hair-dwelling creatures such as lice, ticks, fleas and the like, she’s likely to find men with beards much less attractive.
It’s on an unconscious level, of course. But from the viewpoint of her inner animal brain, who wants to pucker up to a mouth fringed by a thicket of hair that might contain tiny, squirmy, maggot-like creatures?

I’m taking this personally, as a bearded man with a fondness for creepy crawlies. For the record, my beard is respectably groomed and does not contain any squirmy maggots, and I find the implication offensive and unfounded. Do we go around suggesting that women grow their hair longer than men (usually) in order to provide a nesting ground for ticks and lice, or do we consider tastefully coiffed hair to be an attractive feature? Why assume that beards or any other hair repulsive?

So I read the paper, A multivariate analysis of women’s mating strategies and sexual selection on men’s facial morphology, by Tessa R. Clarkson, Morgan J. Sidari, Rosanna Sains, Meredith Alexander, Melissa Harrison, Valeriya Mefodeva, Samuel Pearson, Anthony J. Lee and Barnaby J. W. Dixson. I was even less impressed. In particular, they are trying to associate a phenomenological study of women’s reports of their preferences of a set of photographs with an evolutionary effect of sexual selection, which is a rather long reach. We know that fashions in hair styles vary wildly with time and location with a rapidity that cannot be associated with reproduction — shall we look at big hair styles from the 1980s and draw inferences about paleolithic mating preferences? Beards go in and out of fashion all the time, so a sample taken in 2019 of Western women’s taste in North European male faces (yes, they explicitly used only faces of a small ethnic subset) is only a snapshot of a narrow cultural preference in a tiny slice of time that cannot be interpreted as a significant biological factor.

Here’s the abstract.

The strength and direction of sexual selection via female choice on masculine facial traits in men is a paradox in human mate choice research. While masculinity may communicate benefits to women and offspring directly (i.e. resources) or indirectly (i.e. health), masculine men may be costly as long-term partners owing to lower paternal investment. Mating strategy theory suggests women’s preferences for masculine traits are strongest when the costs associated with masculinity are reduced. This study takes a multivariate approach to testing whether women’s mate preferences are context-dependent. Women (n = 919) rated attractiveness when considering long-term and short-term relationships for male faces varying in beardedness (clean-shaven and full beards) and facial masculinity (30% and 60% feminized, unmanipulated, 30% and 60% masculinized). Participants then completed scales measuring pathogen, sexual and moral disgust, disgust towards ectoparasites, reproductive ambition, self-perceived mate value and the facial hair in partners and fathers. In contrast to past research, we found no associations between pathogen disgust, self-perceived mate value or reproductive ambition and facial masculinity preferences. However, we found a significant positive association between moral disgust and preferences for masculine faces and bearded faces. Preferences for beards were lower among women with higher ectoparasite disgust, providing evidence for ectoparasite avoidance hypothesis. However, women reporting higher pathogen disgust gave higher attractiveness ratings for bearded faces than women reporting lower pathogen disgust, providing support for parasite-stress theories of sexual selection and mate choice. Preferences for beards were also highest among single and married women with the strongest reproductive ambition. Overall, our results reflect mixed associations between individual differences in mating strategies and women’s mate preferences for masculine facial traits.

Among the flaws are the aforementioned narrow set of sample images — sorry, you’re not going to get to choose whether you’d like a one-night stand with Idris Elba vs. a long-term relationship with Hugh Grant — but also, the study was executed using Amazon’s Mechanical Turk, which is going create unanalyzed biases in the respondent population. It also apparently created a far more diverse respondent population than was represented in the target images, so who knows what effect that had.

And really, the game they played was a variation on “shag, marry, kill”: would you have a quickie relationship with this face? Would you like to live with this face for months and months? Is this face totally unattractive to you? It’s the most superficial analysis possible. How many of you chose your mate because of their appearance, and nothing else, and prioritized conventional attractiveness over all other attributes? This is a meaningless study. You can’t say anything about human evolution with a study that reduces a complicated process, courtship behavior and reproduction in humans, to such a trivial scope.

Yeah, sure, you can talk all you want about Tinder and swiping left or swiping right, but that’s about transient relationships and not long-term investment in offspring.

Anyway, you want the results? Here you go.

Mean ratings (±1 s.e.m.) for attractiveness when judging short-term (a) and long-term (b) relationships for bearded (black circles) and clean-shaven (white circles). The composites were manipulated to appear 60% and 30% feminized, unmanipulated, and 30% and 60% masculinized. Note that the full rating scale ranges from 0 to 100.

Oh, wait, maybe the study isn’t so bad, since it found that bearded men are generally preferable to clean-shaven men, both for long term and short term relationships, clearly the correct result. Also women prefer the unmodified or slightly masculinized photographs, so men — be yourself, or use just a little subtle makeup.

But no…you know this result is going to vary across time and cultures. Wait a decade, and those results could flip.

This leads into the next part of the paper, which is to look at how the results vary with women’s phobias about disease and parasites and sex and morality. They even suggest a hypothesis: “The ectoparasite avoidance hypothesis proposes that ancestral humans underwent additional loss of body hair as it lessened the potential for disease-carrying ectoparasites to proliferate.” But they can’t test this hypothesis! These data are so ephemeral that you can’t use them to describe human behavior during the long period of our evolution, and further, I’d argue that it doesn’t even hold up, given that a) we don’t know much about the timing of hair loss in the human lineage, and b) they’re examining a persistent phenomenon, male facial hair. If there was selection to get rid of beards full of squirmy maggots, how come we still have them? The beards, that is, not the squirmy maggots. I’d also ask what’s special about humans, since most mammals are covered with hair; are chimpanzees uninterested in selecting mates lacking in parasites?

The authors administered a test to measure respondents attitudes about 4 dimensions of disgust and then correlated that with their measures of attractiveness. The idea was that if a woman was particularly repulsed by the sight of arthropods (“ectoparasite disgust”), then they ought to rate men with beards as less attractive, because who knows what might be lurking in that thatch?

That was sort of the result they got, that excited the popular press the most.

The associations between women’s ectoparasite, moral, pathogen and sexual disgust and their attractiveness ratings for male beardedness when judging bearded faces (red line) and clean-shaven faces (green line). Data show regression lines (±95% confidence interval). Note that the full rating scale ranges from 0 to 100.

Look at the ectoparasite avoidance and pathogen disgust graphs on the left. The attractiveness of bearded men did decline as the women subjects exhibited increasing queasiness about parasites…but I also notice that no matter how sensitive the women were, they still (on average) found bearded men more attractive than cleanshaven men. Which I interpret to mean that if I cultivated spiders in my beard, I might be slightly less attractive to more women, but I’d still be prettier than the beardless boys. I don’t see how it provides evidence that beardlessness has a selective advantage; I take it to mean that the forces behind the growth of male facial hair are more complex and diverse than can be accounted for by one simplistic hypothesis.

The moral disgust graph is complicated. Increasing moral disgust means the respondent attaches more importance to upright behavior, that they are repulsed by criminality, for instance. Those women find both bearded and clean-shaven men more attractive, and that may be a consequence of, for instance, avoiding homosexuality, to speculate a bit. Every man looks prettier when you’re afraid of falling for the wrong sex.

The sexual disgust scale is the only one that shows a preference for clean-shaven men over bearded ones at the extreme end. Sexual disgust is a measure of the importance of sexual propriety (no incest, for example) and also of the desirability of an individual for reproduction — again to speculate, maybe beards are a way of concealing biological defects, so they are less attractive.

Finally, though, these measures of attractiveness are so deeply subject to trends and fashions and wildly varying personal taste that they cannot be used to test hypotheses of human evolution. This would have been a better paper if they’d avoided making the unwarranted claims of deep biological meaningfulness…but then, it wouldn’t have been picked up by the tabloids and news agencies, now would it?

Oh, how I detest textbook publishers

I was not going to go into the university today. It is miserable outside — bitter cold, stiff winds, piles of drifting snow — and I had resolved to stay warm indoors and focus on getting prepped for spring term classes. And I did! I was about to post the first homework assignment for my class, and I was double-checking all the details, when I noticed that the list of textbook problems was from the 10th edition of Concepts of Genetics, while the syllabus specifies the 11th edition. Oh no, crap. If there’s one thing I know, it’s that this publisher loves to fuck around with problem numbers. They may not have changed a thing in the content between editions, but they will still juggle around the order of the problems and call it a new “edition”.

I did not have a copy of the textbook at home. Therefore, I had to put my pants on — and boots and scarf and hat and gloves and heavy coat — and wade out into the wilderness to my office. Yikes, but it was cold. There were knee-high drifts of snow on the sidewalks at the university, which has not been cleared at all since we’re still officially on break. I nearly lost my hat to the wind twice. I stumbled in one drift and twisted my ankle…I think it’s OK, but it was also numbed by the cold, and I’ve been discovering that all I have to do is roll over in bed nowadays and something will ache, so I’ll probably be feeling that tomorrow. But I got my copy of the textbook! I staggered home, sat down, and started to pull out the changes when…sudden terrifying thought, what is the latest publishers edition?

It’s 12. Not 11, not 10, 12. I don’t have a copy of that. Goddammit.

Oh well, I’ll do the extra work I’ve often had to do: I post the problem numbers of the edition I’ve got, with the beginning phrase of the problem, and tell the students to figure it out. You know what we’re doing this first week? A review of basic probability and statistics, and an overview of simple Mendelian genetics, stuff that hasn’t changed in 50 to a hundred years, but we’re going to gouge $174.25 out of the students to get the latest arrangement of textbook problems.

(I do tell the students they should feel free to order older, much cheaper editions because of this absurdity.)


On the bright side of things, I had a chance to duck into the lab and check on Mrs Yara and Mr Chad. No eggs yet, but I’ll put some photos below the fold.

[Read more…]

What good are virgins in a developmental biology lab?

I’m back! I survived my trek to the lab! It wasn’t as bad as I made it sound — the wind is biting, and the snow is coming down sideways, but it’s fairly light so far — so, except for the wolves and the yeti that tried to block my path, it was a reasonably easy trip.

There were reasons I was eager to go in. I’ve been getting anxious, because I’ve got all these new generation spiders, and they’re all virgins because of the shortage of males. I need them to lay eggs! I’ve got new students who want to work with me this semester, and it’s hard to do developmental biology with a bunch of virginal female spiders not producing embryos for us.* That one pair mated yesterday was a promising start, so there were a few things I wanted to do.

  • See if Yara had produced an egg sac. She hadn’t, but there were signs that she was nesting, with some debris pulled up into her favorite corner (which makes me think she might be Parasteatoda tabulata, too.)
  • Make sure her current partner, Chad, hadn’t been eaten. He was fine.
  • Feed her some more, both to make her less likely to eat the male, but also to fuel a little more egg production. Mission accomplished.

Does she look plump to you? She does to me, a little bit. Also her abdomen is paler than it was yesterday, I think. Come on, mama!


*There are some behavioral experiments we could do, but really, development is where my brain is at. We’ll see what interests the students.

Ferda! Also, Yara ♥ Chad

You’ve missed the spiders, haven’t you? I was away for a week, and only today had time to spend a long morning working with them. They’ve been growing; I fed them a lot before I left, and when I came back I found that almost all of them had molted.

I gave them all a lot of flies today, because we’ve got another of those blizzards coming in tomorrow, and I may not be able to make it into the lab for a few days.

One big problem is that I’m down to only two Parasteatoda males, and no males for Steatoda triangulosa. This happened last year, too — the males are so much more fragile and they die off more rapidly. I resolved to invest more effort in raising da boys so this wouldn’t happen, and I didn’t do enough, obviously. Next year! I’ll do better! Or if I get a nice clutch of eggs to hatch soon, I’ll segregate the males and females as early as possible and make sure they’re well fed and protected.

Which may happen…

This is Chad, the biggest male I’ve got. Look at those bulging palps at the front of his head!

Chad got his chance. I put him in the cage with Yara, and they hit it off immediately. Yara scuttled over to him, and there was a bout of touchy-feeling probing, legs everywhere, and then she presented her epigyne to him, and he scurried right in there with those masculine palps. No fighting! No running away! I have high hopes for this encounter.

Aww, isn’t that sweet? I’m leaving them together for the next few days to make sure, then Chad is going to be introduced to some other ladies around the lab.

When will the criticisms of evolutionary psychology sink in?

I’ve been complaining for years, as have others. The defenders of evolutionary psychology just carry on, doing more and more garbage science built on ignorance of evolutionary biology, publishing the same ol’ crap to pollute the scientific literature. It’s embarrassing.

Now Subrena Smith tries valiantly to penetrate their crania. It’s a familiar explanation. She sees it as a matching problem between their claims about the structure of the brain and behavioral history.

The architecture of the modern mind might resemble that of early humans without this architecture having being selected for and genetically transmitted through the generations. Evolutionary psychological claims, therefore, fail unless practitioners can show that mental structures underpinning present-day behaviors are structures that evolved in prehistory for the performance of adaptive tasks that it is still their function to perform. This is the matching problem.

In a little more detail…

Ancestral and present-day psychological structures have to match in the way that is needed for evolutionary psychological inferences to succeed. For this, three conditions must be met. First, determine that the function of some contemporary mechanism is the one that an ancestral mechanism was selected for performing. Next, determine that the contemporary mechanism has the same function as the ancestral one because of its being descended from the ancestral mechanism. Finally, determine which ancestral mechanisms are related to which contemporary ones in this way.

It’s not sufficient to assume that the required identities are obvious. They need to be demonstrated. Solving the matching problem requires knowing about the psychological architecture of our prehistoric ancestors. But it is difficult to see how this knowledge can possibly be acquired. We do not, and very probably cannot, know much about the prehistoric human mind. Some evolutionary psychologists dispute this. They argue that although we do not have access to these individuals’ minds, we can “read off” ancestral mechanisms from the adaptive challenges that they faced. For example, because predator-evasion was an adaptive challenge, natural selection must have installed a predator-evasion mechanism. This inferential strategy works only if all mental structures are adaptations, if adaptationist explanations are difficult to come by, and if adaptations are easily characterized. There is no reason to assume that all mental structures are adaptations, just as there is no reason to assume that all traits are adaptations. We also know that adaptationist hypotheses are easy to come by. And finally, there is the problem of how to characterize traits. Any adaptive problem characterized in a coarse-grained way (for example, “predator evasion”) can equally be characterized as an aggregate of finer-grained problems. And these can, in turn, be characterized as an aggregate for even finer-grained problems. This introduces indeterminacy and arbitrariness into how adaptive challenges are to be characterized, and therefore, what mental structures are hypothesized to be responses to those challenges. This difficulty raises an additional obstacle for resolving the matching problem. If there is no fact of the matter about how psychological mechanisms are to be individuated, then there is no fact of the matter about how they are to be matched.

One problem is that evolutionary psychologists all seem to think that their assumptions are obvious — and if you don’t agree, why, you must truly hate Charles Darwin and be little better than a creationist. Man, it’s weird when the intelligent design creationists are all calling you a dogmatic Darwinist, and the evolutionary psychologists are accusing you of being an intelligent design creationist. They’re both wrong.

Those sure are funny-looking spiders, Mary

While she’s away, I’m expected to take care of my wife’s animals, but so far I’m finding them mystifying. I can’t identify any of them, and I have a large collection of books for classifying North American invertebrates. I think they might be new species, never before seen by humans.

This one I’m calling a grey-backed bark spider.

This one is a red-headed pig-eating spider. As you can see, she has captured a bit of pork belly in the curiously colored red silk of her nest.

She better come back soon before I get even more confoozled.

How to make science more inclusive

We can be better, and the Society for Integrative and Comparative Biology shows how it’s done. Their journal published an article describing the steps they were taking to make SICB more inclusive and representative, and show the state of affairs in their membership.

The ethnic (top panel) and gender (middle panel) composition of SICB membership and the ICB editorial board (data from 2019) compared with the US and NSF census (data from 2015 US census and 2017 NSF survey). Bottom panel: Gender composition of the ICB editorial board since the journal’s foundation (median per decade).

The top graph is the ethnic distribution, and while the percentage of people of color in the society is somewhat lower than it is in the population of Ph.D.s, and significantly lower than the overall population, the key thing is that the population in leadership roles, that is the editorial board of their journal, is proportional to the population in the general membership. That sets the direction they’ll be taking.

The second graph is the gender distribution, and it’s roughly a healthy 50:50; maybe women are a little over-represented on the editorial board, but that’s also a smaller population with more variation. It’s worth noting, too, that over half the population of Ph.D.s in the country are women, so you’d better start paying more attention. Before the usual neandertals start whining about how women are in more ‘soft’ disciplines, note that over half the population of SICB, a highly technical field, are women. I should also point out that it doesn’t matter what discipline you’re talking about, all those non-STEM fields also require rigor and discipline and hard work.

The real eye-opener is that third graph, which shows the history of SICB. Sixty years ago, it was a very ‘masculine’ organization, with only about 10% of the SICB editorial board women; it rose to about one quarter women in the 80s, surging abruptly to 60% this year. That is a big deal. Changing the gate-keepers opens up new opportunities.

Researchers from non-prestigious institutions or minority groups face hurdles in publishing and in obtaining funding; for example, female scientists publish relatively less and get fewer citations than their male counterparts due to bias, such as gender differences in self-citation. Just as female and non-white authors remain underrepresented in the USA, so do authors from low-income and Global-South countries. In many scientific areas male, majority ethnic, and US scientists remain over-represented as gatekeepers (peer reviewers, editors) and lead authors. Although editorial boards have become more inclusive, most journals in the life sciences are still led by editors from US institutions and by men: in 2018, of the top 100 journals in life sciences as ranked in a 2009 study, 78 had a male editor in chief and 68 had an editor in chief affiliated with a US-based institution. Of the 22 female editors in chief, 17 were affiliated with US-based institutions. In contrast, women made up more than half of all PhDs granted in the USA in 2017 (Fig. 1), and the USA granted fewer than a quarter of doctoral degrees worldwide in 2018.

I’ve been to SICB a few times (not as much as I’d like, but their January annual meeting time doesn’t fit my schedule well), and there’s always been a lot of interesting work presented there. The directions they’re taking only make me want to go more often.

No spiders!

I took Iliana on a little survey trip around her house, and was mildly disappointed. She lives in this housing development of too-big houses that have some kind of disturbing style of permitted paint jobs — absolutely everything is in muted earth tones. Dull browns, grays, an occasional dark brick color, but nothing bright at all. The wildlife around here is the same. We spotted a prairie dog colony that yip-yip-yipped at us.

Brown everywhere. Then I found a fly on Iliana’s house, and was amazed: this is the color template for all the houses around here! The developers must have seen these little flies buzzing around and decided to paint everything to match.

There were no spiders in sight. Finding spider food gives me hope, though.