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Male Scent May Compromise Biomedical Research
April 29, 2014 1:57 PM   Subscribe

Jeffrey Mogil’s students suspected there was something fishy going on with their experiments. They were injecting an irritant into the feet of mice to test their pain response, but the rodents didn’t seem to feel anything. “We thought there was something wrong with the injection,” says Mogil, a neuroscientist at McGill University in Montreal, Canada. The real culprit was far more surprising: The mice that didn’t feel pain had been handled by male students. Mogil’s group discovered that this gender distinction alone was enough to throw off their whole experiment—and likely influences the work of other researchers as well.

Olfactory exposure to males, including men, causes stress and related analgesia in rodents
We found that exposure of mice and rats to male but not female experimenters produces pain inhibition. Male-related stimuli induced a robust physiological stress response that results in stress-induced analgesia. This effect could be replicated with T-shirts worn by men, bedding material from gonadally intact and unfamiliar male mammals, and presentation of compounds secreted from the human axilla. Experimenter sex can thus affect apparent baseline responses in behavioral testing.
[Convenient imgur mirror of the paper for the so inclined]
posted by Blasdelb (82 comments total) 67 users marked this as a favorite

 
Wow.
posted by maryr at 1:59 PM on April 29


That's kind of amazing.
posted by Joey Michaels at 2:01 PM on April 29


So... men are literally biologically worse at science.
posted by Etrigan at 2:02 PM on April 29 [142 favorites]


But women cause more pain? Or at least, don't lessen it.
posted by maryr at 2:03 PM on April 29 [2 favorites]


Thanks for the link...fascinating stuff...
posted by Alexandra Kitty at 2:04 PM on April 29


Fascinating. Wow.
posted by zarq at 2:07 PM on April 29


Whoa.

I do wonder sometimes why more science fiction writers are not huddled up in a corner sobbing with despair at how bizarre the real world actually is and how hopeless it is to try and improve on its strangeness in fiction.
posted by MartinWisse at 2:11 PM on April 29 [52 favorites]


I don't know a ton about the way lab strains are created - is there any likelihood that this response is specific to lab mice? (As in, when stressfully being raised by the mean men in white coats, this particular stress response confers a reproductive advantage.)
posted by PMdixon at 2:11 PM on April 29 [9 favorites]


But women cause more pain? Or at least, don't lessen it.

I have a spookish dog, and "stress-induced analgesia" is not actually a good thing IME. It can lead to things like, "pawing at a cage well past the point of bleeding abrasions" and other maladaptive things.
posted by muddgirl at 2:14 PM on April 29 [7 favorites]


Of mice and men.

I wonder if they can somehow test this with friendly males.
posted by preparat at 2:16 PM on April 29 [1 favorite]


If further experiments and study prove this finding, it seems there are some interesting implications for the social mediation of pain in people, too, since the mechanism of action (so to speak) is claimed to be analogous in all mammals.
posted by clockzero at 2:19 PM on April 29 [4 favorites]


I don't know a ton about the way lab strains are created - is there any likelihood that this response is specific to lab mice? (As in, when stressfully being raised by the mean men in white coats, this particular stress response confers a reproductive advantage.)

That's a really interesting thought. I know there's a gender bias in STEM in general; I don't know about the field of model organisms in particular. But if the majority of scientists breeding lab mice are male, it's entirely possible that a genetic aversion to human male scent could be selected for inadvertently.

I mean, I can't think of a plausible scenario off the top of my head, but then I know almost nothing about how these animals are bred. Surely some lab-coat-wearing MeFite will come to our rescue.
posted by escape from the potato planet at 2:22 PM on April 29 [2 favorites]


This confirms everything I've always suspected about men.
posted by Flashman at 2:22 PM on April 29 [6 favorites]


The fun bit was that the paper showed that men literally scared the crap out of the mice.
posted by NoxAeternum at 2:22 PM on April 29 [6 favorites]


"Baby, I'm here to take your pain away...no, really. It's SCIENCE!!!"
posted by Mental Wimp at 2:26 PM on April 29 [1 favorite]


How do we know this isn't a rodent's reaction to, say, Axe body spray?
posted by asperity at 2:26 PM on April 29 [18 favorites]


I don't know a ton about the way lab strains are created - is there any likelihood that this response is specific to lab mice? (As in, when stressfully being raised by the mean men in white coats, this particular stress response confers a reproductive advantage.)

I saw a great talk about lab strains verses inbred wild strains and the HUGE differences in their innate immune responses at Tufts Medical School, but I can never remember the name of the researcher. The gist of it was that the immune systems of common lab strains had big over-reactions to low threat viruses but those of wild strains (which had been captured somewhere outside Jackson labs and then brought inside and bred for several generations - so not mice that had ever seen the sky) just ignored it. It was pretty eye-opening considering how much basic immune system research is done with mouse models. (I chose not to tell my friend who was about to defend her PhD mouse immunology work about the stuff, I figured it would only freak her out.)
posted by maryr at 2:29 PM on April 29 [7 favorites]


Anecdotally I know that there are at least a bunch of murine labs where this effect is already informally taken into account, where female students were just serendipitously discovered to more often be mouse whisperers, but handler sex appears to really be something that needs to be reported in methods sections and more universally controlled for.
posted by Blasdelb at 2:29 PM on April 29 [12 favorites]


It's tricky too because mouse work (at least mouse housekeeping) is sometimes considered less desirable and less prestigious lab work, so just saying "Oh, the girls will handle the mice," is problematic too.
posted by maryr at 2:31 PM on April 29 [22 favorites]


(By which I do not mean to denigrate mouse work - most people I know just tend to hand it off to students as soon as possible, so I just have that impression.)
posted by maryr at 2:32 PM on April 29 [1 favorite]


Science is awesome.
posted by stoneweaver at 2:38 PM on April 29 [3 favorites]


But it's not really a male v female thing though, right? Because it's olfactory, so it's presumably just the rats' reaction to different pheromone combinations. Granted, these tend to fall along sex lines of course, but not universally (you could have, say, a female sexed researcher with pheromones more typically exhibited by men). I wonder if they plan to narrow it down further.

Also I'm wondering if Metafilter might consider adding a Grimace Scale feature.
posted by Lutoslawski at 2:39 PM on April 29 [3 favorites]


If - if - this turns out to be true, I'm baffled as to why it would be true - how would such a circumstance be selected for, what "good" would it do?
posted by Greg_Ace at 2:40 PM on April 29


Cue Richard Scary picture of a lady mouse standing on a chair, lifting her skirts and shrieking "Good heavens! It's a man!"
posted by Ryvar at 2:40 PM on April 29 [34 favorites]


They were injecting an irritant into the feet of mice to test their pain response, but the rodents didn’t seem to feel anything...Mogil has studied pain for 25 years.

Hey, fuck you, buddy. How many times you gotta keep doing that?
posted by turbid dahlia at 2:42 PM on April 29 [20 favorites]


If - if - this turns out to be true, I'm baffled as to why it would be true - how would such a circumstance be selected for, what "good" would it do?

Presumably evolved as a defense mechanism of some sort. If a male predator is about, maybe the likelihood of a fight or whatever was greater, so they went into stress drive and feel less pain as a sort of fight prep.
posted by Lutoslawski at 2:42 PM on April 29 [3 favorites]


Greg, from the article: "He suspects the rodents are reacting to scent chemicals that male mammals have produced for eons. “It’s a primordial response,” he says. “If you smell a solitary male nearby, chances are he’s hunting or defending his territory.” If you’re in pain, you’re showing weakness."
posted by maryr at 2:43 PM on April 29 [1 favorite]


But then I wonder if it's typically the case that rodent predators tend to be the male of their species?
posted by Lutoslawski at 2:43 PM on April 29 [3 favorites]


I don't know a ton about the way lab strains are created - is there any likelihood that this response is specific to lab mice? ...

posted by PMdixon


I think you've got it, PMdixon, and I'd bet it's an epigenetically rather than genetically determined trait.
posted by jamjam at 2:43 PM on April 29 [4 favorites]


Most of my research experience is with rats, and the twin forces of hand-rearing and familiarization are subtle but important factors. Rats who get daily handling by humans (of either gender) find later handling much less stressful, and that stress response is decreased even further if they are specifically familiar with your scent, particularly if your arrive is a reliable predictor of imminent food. It's very possible that some additional effect of gender exists, but I would be surprised if the magnitude of that effect were greater than that of regular exposure and skillful handling.

This creates a tension in many labs, as the people in charge often are the most experienced, but are compelled by competing duties (analysis, writing, teach) to delegate that work to less-experienced subordinates. One of the major factors distinguishing a high-caliber lab from a mediocre one is how well-trained and well-supervised these lab technicians are at animal handling and animal care, which can be a fatal source of noise if neglected.

That said, I'm not certain how well the above generalizes to mice. Rats are generally much more pro-social towards humans than mice are, so it may well be that the benefits of dutiful handling are much less pronounced. Certainly, the reported gender effect should be enough to cause people to sit up and think seriously about (1) what can be done about it in the short run and (2) what further experiments should be performed to better understand the phenomenon.
posted by belarius at 2:44 PM on April 29 [13 favorites]


I think you've got it, PMdixon, and I'd bet it's an epigenetically rather than genetically determined trait.

So like, because most researchers used to be men, some generations back this line of lab rodents evolved the ability to feel less pain from male researchers, is your idea? Interesting, but it wouldn't explain why females produce less of a stress response, unless females were typically like rescuing their grandpas or whatever.
posted by Lutoslawski at 2:45 PM on April 29 [3 favorites]


I sent this info to my neuroscience professor friend who wrote back almost instantaneously: "Holy shit!!!!!!! I am tracking this down. THANK YOU!"
posted by komara at 2:48 PM on April 29 [4 favorites]


If - if - this turns out to be true, I'm baffled as to why it would be true - how would such a circumstance be selected for, what "good" would it do?

I think it's premature to assume or conclude that this is a purely evolved reaction. Although the mice in the experiment are "experimentally naive", they still had time to develop learned behaviors that haven't been accounted for (as far as I can tell from a quick skim). I can think of half a dozen different hypotheses I'd want to test with rats and mice from birth before forming any conclusions.
posted by muddgirl at 2:51 PM on April 29 [3 favorites]


I find this fascinating. It's also pretty much the last story I'd like to run into in the social media age.
posted by MillMan at 2:52 PM on April 29 [1 favorite]


I mean, to be fair, if you've ever been in a men's gym locker room, you'll know that an overwhelming scent of testosterone can indeed be stressful and cause an instinctual production of Man Face.
posted by Lutoslawski at 2:57 PM on April 29 [2 favorites]


> "He suspects the rodents are reacting to scent chemicals that male mammals have produced for eons. “It’s a primordial response,” he says. “If you smell a solitary male nearby, chances are he’s hunting or defending his territory.” If you’re in pain, you’re showing weakness."

Not just rodents.
posted by benito.strauss at 2:57 PM on April 29 [1 favorite]


Most likely explanation given one experiment: experimental error.

Otherwise: holy crap that's interesting.
posted by Fists O'Fury at 3:01 PM on April 29


No woman, no cry?
posted by mosk at 3:05 PM on April 29 [14 favorites]


I told our gerbil I'm sorry I stress him out. :(
posted by edheil at 3:14 PM on April 29 [7 favorites]


Lutoslawski: "If - if - this turns out to be true, I'm baffled as to why it would be true - how would such a circumstance be selected for, what "good" would it do?

Presumably evolved as a defense mechanism of some sort. If a male predator is about, maybe the likelihood of a fight or whatever was greater, so they went into stress drive and feel less pain as a sort of fight prep.
"

I confirmed this in the bubble popping thread. (Or rather, with my predator man boss around, I tense up and have fight or flight, ready to deal with any shock or pain in the way). Once I get home. Unwind and owwwwwwwwww. :(
posted by symbioid at 3:26 PM on April 29 [1 favorite]


Assuming it's true (and the paper does look pretty convincing to me at first glance), you have to wonder how it squares with the evidence that mice can inherit a learned stress response to a smell, presumably via epigenetic modifications.

In the three (British) labs where I've worked with mice, the technical staff looking after them day-to-day have been overwhelmingly female. Given that biology departments (at least, in my discipline) are pretty female-dominated at the bench worker level, it seems reasonable to assume that most of the animal experimenters there are female too. It'd be interesting to know the sex makeup of their lab, and to see whether the same patterns crop up in labs with a different balance.

Blasdelb - Anecdotally I know that there are at least a bunch of murine labs where this effect is already informally taken into account, where female students were just serendipitously discovered to more often be mouse whisperers...

Two of the best animal handlers I've met -- both women with years of experience working with mice and training others to do so -- have told me before that they think mice tend to prefer women. It's not absolute, as I've definitely known women who spook the mice, and the mice I've been handling daily for the last year are noticeably more chilled with me (male) than with a woman than haven't encountered much before. But I'm definitely willing to accept their judgement as strong supporting evidence.

belarius: like your rats, mice who're regularly handled from birth are very calm in comparison to ones who're left to their own devices for the first month or two. I'm pretty sure that mine are more relaxed with me than with most other people, but it could be that they're used to my handling style, rather than being used to me specifically. They're not as docile as a trained rat can be, but it's a very noticable difference in behaviour.

Lutoslawski - If a male predator is about, maybe the likelihood of a fight or whatever was greater, so they went into stress drive and feel less pain as a sort of fight prep.

Not just predators. At least in some strains of lab mice, males are generally complete arseholes to animals that they're not already living with. Introduce a male to an unfamiliar male and, if they can't avoid each other (or are just in an ornery mood) they'll get into a pretty nasty fight. Females meeting new females get territorial too, but it's generally less violent. Males meeting new females goes pretty much how you'd expect (attempted assertion of dominance, often mating). I should stress that this is something I've been taught, not seen demonstrated: introducing unfamiliar animals to each other, except male/female pairs for breeding, isn't done.
posted by metaBugs at 3:34 PM on April 29 [5 favorites]


An adaptation doesn't have to be perfect to convey a fitness advantage. A neurological system that allows for early detection and appropriate response to 50% of predators is still better than nothing. People often forget that, when they're talking about evolution; it doesn't have to be perfect or even sensible, it just has to work and be better than the prior alternative.

People also tend to forget that evolution isn't all powerful. It's not like Evolution looked at mice one day, thought about all the ways in which their predator detection and response systems could theoretically be improved, and picked this one. Rather, what presumably happened is that a minor, random change was made to a gene that by chance caused the mouse who had it to freak out whenever it detected certain male pheremones. This turned out to give its descendants an advantage in avoiding predators, and it stuck around. The issue of some hypothetical superior adaptation never came up.

Of course, this all assumes that the effect they are seeing is real and that it has a genetic origin. As others have said this is far from certain just from this one paper, though you can bet people will be following it up.

Crap like this happens all the time in biology. For instance in herpetology we're just starting to agree that it's better to measure your frogs while alive or freshly killed than to do it after they've been pickling in ethanol for who knows how long, because their squishy little bodies get all distorted. Not severely distorted, but unpredictably and progressively distorted and certainly significantly distorted when your morphometric analysis relies om caliper measurements being accurate down to 0.1mm. Nobody checked on this until 1982 (because it involves a lot of tedious measurement and remeasurement and is not the kind of paper that's going to make anyone's reputation, plus you risk pissing off a bunch of established researchers by summarily invalidating their entire careers) and even now most people just don't think about it, though the idea is starting to gain traction. Such are the vagaries of science.
posted by Scientist at 3:36 PM on April 29 [15 favorites]


I just have to say that science is awesome.
posted by feckless fecal fear mongering at 3:44 PM on April 29


men: scientifically proven to be ruiners
posted by elizardbits at 3:54 PM on April 29 [11 favorites]


>Not just predators. At least in some strains of lab mice, males are generally complete arseholes to animals that they're not already living with.

This is my thought as well -- could this reaction meant to provoke a stress response to other mice that are male, and the reaction to male predators and scientists is a side effect? It seems unlikely that male predators are more dangerous to mice than female ones. But both female and male mice would have reason to expect trouble from a male mouse that they wouldn't from a female. I'm not a scientist, but I have kept mice, and it's basic to mouse-keeping that male mice won't live together without serious fighting.
posted by Erasmouse at 4:01 PM on April 29 [3 favorites]


"The rodents showed significantly fewer signs of pain (an average of a 36% lower score on the grimace scale) when a male researcher was in the room than when a female researcher—or no researcher at all—was there."

Slartibartfast coughed politely.

``Earthman,'' he said, ``. . .These creatures you call mice, you see, they are not quite as they appear. They are merely the protrusion into our dimension of vast hyperintelligent pan-dimensional beings. The whole business with the cheese and the squeaking is just a front.''

The old man paused, and with a sympathetic frown continued.

``They've been experimenting on you I'm afraid.''

Arthur thought about this for a second, and then his face cleared.

``Ah no,'' he said, ``I see the source of the misunderstanding now. No, look you see, what happened was that we used to do experiments on them. They were often used in behavioural research, Pavlov and all that sort of stuff. So what happened was hat the mice would be set all sorts of tests, learning to ring bells, run around mazes and things so that the whole nature of the learning process could be examined. From our observations of their behaviour we were able to learn all sorts of things about our own ...''

Arthur's voice tailed off.

``Such subtlety ...'' said Slartibartfast, ``one has to admire it.''

``What?'' said Arthur.

``How better to disguise their real natures, and how better to guide your thinking. Suddenly running down a maze the wrong way, eating the wrong bit of cheese, unexpectedly dropping dead of myxomatosis, --- if it's finely calculated the cumulative effect is enormous.''

posted by markkraft at 4:02 PM on April 29 [15 favorites]


> They were injecting an irritant into the feet of mice to test their pain response, but the rodents didn’t seem to feel anything...Mogil has studied pain for 25 years.

Hey, fuck you, buddy. How many times you gotta keep doing that?


Until we have better treatments for chronic pain in humans, I hope.
posted by sebastienbailard at 4:03 PM on April 29 [3 favorites]


On behalf of science: Whoopsie.
posted by gingerest at 4:05 PM on April 29


This is yet another one of those fleeting moments where life imitates Kilgore Trout.
posted by usonian at 4:27 PM on April 29 [1 favorite]


Grimace scale. Poor mousies.
posted by maryr at 4:39 PM on April 29


My first reaction was to wonder how the histories of the individual mice are accounted for, that is, if the bias may result from something like men being more frequently associated with stressful situations prior to the experiment. From the paper:

Changing the sex of the technician providing animal husbandry did not alter results, nor did changing the sex of the person administering zymosan.
posted by Casimir at 5:47 PM on April 29 [1 favorite]


This is also sort of interesting on a metaphysical level because one of the big goals of the masculine gender entails denying the experience of pain.
posted by clockzero at 5:56 PM on April 29 [1 favorite]


Does this extend to humans? Well if you have a headache hon, come on over here and smell my armpit.
posted by humanfont at 6:14 PM on April 29 [1 favorite]


Some kind of sexually-selected adaptation for male-male competition is a perfectly good hypothesis as well, and perhaps more likely than predator avoidance. Knowing evolution, it could well be serving both purposes. If it were a male-male thing then you'd expect the trait not to be expressed in females, though. Not that it would be impossible for it to be expressed in both sexes under that type of selection pressure, but it would seem less likely.

The interesting thing here, in my opinion, is that if the effect is real and if it has a genetic basis, there's not any one hypothesis that really neatly explains the phenomenon. Perhaps the lack of a obvious, clear-cut cause is part of the reason why the effect wasn't noticed sooner. It's not very intuitive and it wasn't needed to explain anything up until someone had a hunch that this might be something they need to control for and decided to check.
posted by Scientist at 6:21 PM on April 29


How were the mice acquired? Is it possible that the people who raised the mice were female, but the people who exposed them to scary stimuli (e.g., packing and shipping) were male?
posted by Joe in Australia at 6:27 PM on April 29


Does this extend to humans? Well if you have a headache hon, come on over here and smell my armpit.

Research from 2003 suggests yes.
Scientists at the University of Pennsylvania and the Monell Chemical Senses Center in Philadelphia have found that exposure to male perspiration has marked psychological and physiological effects on women: It can brighten women's moods, reducing tension and increasing relaxation, and also has a direct effect on the release of luteinizing hormone, which affects the length and timing of the menstrual cycle.
posted by Kerasia at 6:28 PM on April 29 [4 favorites]


I don't work in behavioral neuroscience, but this paper is something we've been discussing a lot lately. It doesn't surprise me, though, mice are susceptible to olfactory cues and one of the first things I was told in grad school was to never wear perfume or scented shampoos, because it might throw off someone else's experiments. I knew a postdoc who worked on mouse anxiety projects and was also a cat lover ... whenever she did a behavioral experiment, she had to leave her cat at home and move into her boyfriend's apartment (with a neighbor taking care of the cat) for 1-2 weeks at a time, because otherwise her clothes smelled like cat and the mice freaked out.

if the majority of scientists breeding lab mice are male, it's entirely possible that a genetic aversion to human male scent could be selected for inadvertently.

My experience is that neuroscience, and behavioral neuroscience in particular, trends more female than other STEM branches. Labs I've worked in typically have a standard wildtype strain like C57s and then various sets of transgenics. If you want to do an experiment with C57s, you place an order with Taconic or Charles River, where they are bred, and then in one week your cage of (adult) mice is delivered to the central animal research facilities. So, they would be handled first for most of their life by the people at the vendor, then the shipping process, then later by the general university animal staff on a daily basis, and then the scientists get the mice from the facility daily for experiments and return them at night. For transgenics, you get the original parent transgenic from Jackson Labs or whatever lab first made it, then you maintain the line yourself in the general university facilities, so the same as the above minus the purchasing and shipping steps. The vet techs I've worked with in the departmental facilities at 3 different institutions are overwhelmingly female. I don't know what the typical makeup of Charles River (where the mice in this paper were from) is, but the "husbandry" here I think refers to the animal facility (vivarium) staff.

It looks like the paper authors did their experiments with C57s and CD-1 mice and Wistar rats. I'm not familiar with Wistars or CD-1s, but I would be curious to see how much the results differ with other strains. Lab mice are so inbred that different strains can produce very different data, and I've worked with common strains where it was quite obvious their neurology and general stress levels were ... different ... after so much inbreeding, so it wouldn't surprise me if that was also in play here.

And yeah, like lutoslawski and metaBugs comment, generally male mice are nasty to one another. Ironically, I always prefer working with female mice, because male mice not raised with one another often fight post-op.
posted by angst at 6:28 PM on April 29 [7 favorites]


My first reaction was to wonder how the histories of the individual mice are accounted for, that is, if the bias may result from something like men being more frequently associated with stressful situations prior to the experiment. From the paper:

Changing the sex of the technician providing animal husbandry did not alter results, nor did changing the sex of the person administering zymosan.
posted by Casimir at 14:47 on April 30 [1 favorite +] [!]


I call bullshit that rats are able to differentiate gender that much.

Its probably more likely that all the dudes were wearing axe body spray.
posted by hal_c_on at 6:52 PM on April 29


So... men are literally biologically worse at science.

No, men intimidate science into showing its weaknesses.
posted by Western Infidels at 6:53 PM on April 29 [3 favorites]


Two of the best animal handlers I've met -- both women with years of experience working with mice and training others to do so -- have told me before that they think mice tend to prefer women.

Someone I know has a theory that cats bond best with owners of the opposite gender, and thinking back over my experience with cats, I think he might be on to something. My best guess is, if true, it's some complementary pheremonal-type thing.
posted by orange swan at 7:16 PM on April 29


This is not unprecedented. Female mice have been known for a long time (1959) to spontaneously abort if they smell a strange male's scent nearby, a phenomenon dubbed the Bruce Effect.
posted by benzenedream at 7:29 PM on April 29 [1 favorite]


Wow. Here is something I am perfectly situated to comment on (colloquially at least). I began my career post-undergrad at one of the big mouse suppliers for laboratory animals, both in the vivarium and in the vet tech crew. I have since earned my doctorate, and currently do a significant amount of mouse behavior work. I would consider myself a mouse whisperer. I am also female. Previously as a vet tech, it had been my observation that mice managed by females in the vivarium were a lot less aggressive compared to those managed by males.

I have also noticed that certain suppliers of C57 mice tend to have "angrier" mice compared to other vendors, and I am certain a lot of this has to do with handling. It has been my experience (>10 years*) that who does a behavior experiment can significantly impact the outcome. I have found it particularly important to make sure that the same researcher performs a given behavioral assay, for instance, to reduce variability in the outcome and reduce variability due to handling.

Regardless, this will definitely impact many of my own considerations when planning future experiments. Thanks for this post!

*and I just realized with all that experience I am still merely a post-doc. sigh
posted by nasayre at 7:52 PM on April 29 [17 favorites]


But the Bruce Effect has to do with female rats detecting male's scents.

This is important because it may be evolutionary successful behavior. The female wants her offspring to be biologically successful (reaching the age of maturity where they can have offspring). If they see another male as a threat, they can abort, and have his offspring...which would mean he's less likely to see the babies as food/threat. And then the female's genetic material gets passed on successfully if the rats reach the age of maturity.
posted by hal_c_on at 7:54 PM on April 29


But the Bruce Effect is species-specific! It really is surprising (to me, anyway) that there's a sex effect across species in mammals, while I can see their argument about lone males being likelier to defend territory, there are plenty of species where either sex is likely to prey on rodents given the opportunity, and where larger predator numbers are more threatening.

(Sex effect, not gender effect, BTW - this is presumably about biological sex, not sociosexual roles.)
posted by gingerest at 7:59 PM on April 29


This made me think of The Psychologist Who Wouldn't Do Awful Things to Rats (summary) by James Tiptree, Jr., written from her time as a PhD, which is detailed in the article The Psychologist Who Empathized with Rats: James Tiptree, Jr. as Alice B. Sheldon, PhD. If you can find the story, it's well worth the read, and is put into a new perspective after reading this recent research.
posted by filthy light thief at 8:27 PM on April 29 [1 favorite]


I think findings like this are intriguing, but I also hate essentially untestable propositions like,
“If you smell a solitary male nearby, chances are he’s hunting or defending his territory.” If you’re in pain, you’re showing weakness.
posted by expense-division at 9:20 PM on April 29 [5 favorites]


Changing the sex of the technician providing animal husbandry did not alter results, nor did changing the sex of the person administering zymosan.

Man, those were some dedicated technicians. I'm pretty sure a sex change won't alter your pheromones though.
posted by Tell Me No Lies at 10:33 PM on April 29 [3 favorites]


Funny! But considering that some sex pheromones are sex steroid metabolites (particularly in male mammals), exogenous hormone therapy for gender reassignment might well change pheromone output.
(The problem with being nerdily interested in a topic is you respond to jokes with "well, actually" remarks.)
posted by gingerest at 11:14 PM on April 29 [9 favorites]


Whoa. Fascinating. Thanks for posting this, Blasdelb.
posted by homunculus at 2:19 AM on April 30


maryr: "It's tricky too because mouse work (at least mouse housekeeping) is sometimes considered less desirable and less prestigious lab work, so just saying "Oh, the girls will handle the mice," is problematic too."
Its funny because in my experience these kinds of things are heavily dependent on local culture, where working with mice will be seen as the masculine hardcore thing for non-squeamish guys who do serious science things that males will flock to for some and then the feminine pedestrian thing for those who can't handle serious science stuff for others.

In the lab I worked in as an undergrad, and am still pretty connected to, I get to see this kind of effect form repeatedly first hand because of the lack of stabilizing graduate students making the generations of lab culture run fast, and I find it fascinating. The lab is almost two labs under a single professor working with bacteriophage against two different model organisms, E. coli and Pseudomonas, which need to be kept separated from each other in different rooms because more wild Pseudomonas has a nasty way of killing the shit out of more domesticated lab strains of E. coli and contaminating everything. The 'two' labs are connected, share a professor, share a break room, share a common type of research, share a research community, generally party together, and do everything but infections together; but ever since the 90s when work with the second model organism started they have always both dramatically self segregated by gender and switch every three to four years.

When I started in the lab as a wee little pipette scratcher, I joined the E. coli lab while it was female dominated rather than the Pseudomonas lab, which was male dominated. It was really hard not to get a general sense that everyone sort of internalized how working with Pseudomonas phages was a hardcore medical thing done by future doctors who were doing serious science, while working with E. coli phages was an almost passive thing to do that was just basic research. Then, as the generation who trained me left and I was still there the male students in the generation I trained ended up flocking to me and constructing their own general internalized impression, where the basic research I was doing with E. coli was suddenly the serious science thing done only by people who could handle it while those in the suddenly female Pseudomonas lab were just glorified future nurses. Never mind that female pre-meds were the ones actually going to medical school while male pre-meds mostly washed out, or that all of the students who fucked up and couldn't handle it (aside from the one female heroin junkie) were pretty categorically male, or that the cycles seemed to in general correlate with female student generations needing to clean up various kinds of messes with poorly maintained stocks and useless data as well as male generations building on female efforts, the generalized impression of the worthiness of effort seems to just only follow dudes.

Now seeing the natural experiment play out a third time, it seems obvious to me that it isn't so much disparaged tasks that women get pushed into, but tasks that women do that get disparaged. The task itself is not the dependent factor, but the fact that women are doing it. It is also not like this was some kind of especially sexist environment students are entering into, the professor, who has been working since the 60s when molecular biology was among the worst of boy clubs, works thoughtfully to fight this sort of thing. Indeed, even though it was really me and my work that the impression of the maleness of the E. coli lab was built around, none of my own efforts seemed to do much other than occasionally provoke some thought - like its just this emergent property inherent to how students are raised.
posted by Blasdelb at 3:53 AM on April 30 [24 favorites]


"Man, those were some dedicated technicians. I'm pretty sure a sex change won't alter your pheromones though."
Searching around I can't find any examples of the various indirect ways that this is detectable being tested for trans* people, but I'd be really curious, does anyone know of any?
posted by Blasdelb at 4:54 AM on April 30 [1 favorite]


is the sex of the lab animals made note of?
posted by mdn at 7:01 AM on April 30


Both male and female mice displayed this 'male observer' effect, but female mice did so to a greater degree, Supplementary figure two shows the data
posted by Blasdelb at 7:14 AM on April 30 [1 favorite]


mdn: In this paper, yes.

More generally, I'd assume that the vast majority of people working with mice know and record what they're working with, for purely logistical reasons. The exception is experiments in mice up to ~18 days old, before which they're basically identical to the naked eye, and young enough to be kept together without getting incestuous. It's very quick and simple to do a PCR to test them for a Y chromosome if you're interested though, and IMO good practice. In my field, I know of two fairly recent cases of totally unexpected sex-dependent differences in disease progression/treatment efficacy that could easily have been missed.

That said, a small but non-zero number of papers don't bother to report the animals' sex, which I find utterly baffling.
posted by metaBugs at 7:22 AM on April 30


Reminds me of something from one of Feynman's lectures
Other kinds of errors are more characteristic of poor science. When I was at Cornell, I often talked to the people in the psychology department. One of the students told me she wanted to do an experiment that went something like this--it had been found by others that under certain circumstances, X, rats did something, A. She was curious as to whether, if she changed the circumstances to Y, they would still do A. So her proposal was to do the experiment under circumstances Y and see if they still did A.

I explained to her that it was necessary first to repeat in her laboratory the experiment of the other person--to do it under condition X to see if she could also get result A, and then change to Y and see if A changed. Then she would know the the real difference was the thing she thought she had under control.

She was very delighted with this new idea, and went to her professor. And his reply was, no, you cannot do that, because the experiment has already been done and you would be wasting time. This was in about 1947 or so, and it seems to have been the general policy then to not try to repeat psychological experiments, but only to change the conditions and see what happened.

Nowadays, there's a certain danger of the same thing happening, even in the famous field of physics. I was shocked to hear of an experiment being done at the big accelerator at the National Accelerator Laboratory, where a person used deuterium. In order to compare his heavy hydrogen results to what might happen with light hydrogen, he had to use data from someone else's experiment on light hydrogen, which was done on different apparatus. When asked why, he said it was because he couldn't get time on the program (because there's so little time and it's such expensive apparatus) to do the experiment with light hydrogen on this apparatus because there wouldn't be any new result. And so the men in charge of programs at NAL are so anxious for new results, in order to get more money to keep the thing going for public relations purposes, they are destroying--possibly--the value of the experiments themselves, which is the whole purpose of the thing. It is often hard for the experimenters there to complete their work as their scientific integrity demands.

All experiments in psychology are not of this type, however. For example, there have been many experiments running rats through all kinds of mazes, and so on--with little clear result. But in 1937 a man named Young did a very interesting one. He had a long corridor with doors all along one side where the rats came in, and doors along the other side where the food was. He wanted to see if he could train the rats to go in at the third door down from wherever he started them off. No. The rats went immediately to the door where the food had been the time before.

The question was, how did the rats know, because the corridor was so beautifully built and so uniform, that this was the same door as before? Obviously there was something about the door that was different from the other doors. So he painted the doors very carefully, arranging the textures on the faces of the doors exactly the same. Still the rats could tell. Then he thought maybe the rats were smelling the food, so he used chemicals to change the smell after each run. Still the rats could tell. Then he realized the rats might be able to tell by seeing the lights and the arrangement in the laboratory like any commonsense person. So he covered the corridor, and still the rats could tell.

He finally found that they could tell by the way the floor sounded when they ran over it. And he could only fix that by putting his corridor in sand. So he covered one after another of all possible clues and finally was able to fool the rats so that they had to learn to go in the third door. If he relaxed any of his conditions, the rats could tell.

Now, from a scientific standpoint, that is an A-number-one experiment. That is the experiment that makes rat-running experiments sensible, because it uncovers that clues that the rat is really using-- not what you think it's using. And that is the experiment that tells exactly what conditions you have to use in order to be careful and control everything in an experiment with rat-running.

I looked up the subsequent history of this research. The next experiment, and the one after that, never referred to Mr. Young. They never used any of his criteria of putting the corridor on sand, or being very careful. They just went right on running the rats in the same old way, and paid no attention to the great discoveries of Mr. Young, and his papers are not referred to, because he didn't discover anything about the rats. In fact, he discovered all the things you have to do to discover something about rats. But not paying attention to experiments like that is a characteristic example of cargo cult science.
posted by Blasdelb at 7:25 AM on April 30 [7 favorites]


Funny! But considering that some sex pheromones are sex steroid metabolites (particularly in male mammals), exogenous hormone therapy for gender reassignment might well change pheromone output.
(The problem with being nerdily interested in a topic is you respond to jokes with "well, actually" remarks.)


That's okay, being a general nerd you respond to "well, actually..." with "Oooh, this should be interesting..."
posted by Tell Me No Lies at 11:12 AM on April 30 [1 favorite]


Reminds me of something from one of Feynman's lectures

It reminds me of the Harvard law:

Under the most rigorously controlled conditions of pressure, temperature, volume, humidity, and other variables, any experimental organism will do as it damn well pleases.
posted by Tell Me No Lies at 11:14 AM on April 30


just glorified future nurses

And of course, wanting to be a nurse is an ambition to sneer at because it's a female-dominated profession. Wheels within wheels.

posted by gingerest at 5:54 PM on April 30 [1 favorite]


By the way, this article sent me down a rabbit hole about androstenone perception. (Androstenone is one of the three male axillary pheromones Mogil's group found influenced stress-induced analgesia.) It's been known since the late 1980s that the ability to smell androstenone is a heritable trait (pdf), but people who can't smell it can learn to detect it with prolonged exposure. Overcoming this selective anosmia provides a handy model for neural plasticity.

And it turns out that even within the people who can smell it, there's high variability in what it smells like - some people detect it as a sweet/vanilla scent, and others as a pungent urine-like smell, and there's some evidence that this may be genetic as well. (I've known a bunch of hygienic-enough, sane guys who smelled like pee, at a distance, and I always wondered what was wrong - did they just not shake hard enough, or what? Well, maybe it's me. Specifically, my olfactory neurons.)

Another interesting thing about androstenone is that it's an important contributor to "boar taint", a flavour contaminant in pork products made from male pigs.
posted by gingerest at 6:33 PM on April 30 [6 favorites]


I am also reminded of a lecture I attended by the late, great Judah Folkman, who is otherwise referred to as the "father of angiogenesis." The man could spin the best of the true science tales. One anecdote he related to the audience had to do with measuring blood pressure in mice. Sometimes, the experiments seemed to make sense, other times, no. Eventually they figured out that every time a male was in the room, the blood pressure of the mice would skyrocket. What's more, a male could enter the room, and cause the blood pressure to change. This never happened when females performed the experiments. So, they just decided to only have females perform the experiment. I wonder how they wrote the methods for that paper.
posted by nasayre at 7:25 PM on April 30 [4 favorites]


WOW I've long wondered whether predatory males can use scent (among many things) to induce tonic immobility in their victims. I wonder if human males have this super power more than males of other species.

I'm not musing as a scientist... just as a muserer. A muser. A person who is musing. It would add a whole nother level to survivors experience of tonic immobility. I feel like dominance strategies between humans are so complex and so much of it is way beyond our conscious understanding.

Are we ready to start understanding these things better because it could get weird.
posted by xarnop at 6:55 PM on May 1


Female predatory mammals hunt too, including female cats, dogs, boars, and humans. Not to mention snakes and birds. Not that evolution is logical, but "these lab mice are afraid of men because Men are Hunters" seems like a just-so story at this point.
posted by muddgirl at 7:01 PM on May 1 [5 favorites]


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