[HN Gopher] Are toxoplasma-infected subjects more attractive tha...
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Are toxoplasma-infected subjects more attractive than non-infected
ones?
Author : kloch
Score : 75 points
Date : 2022-04-02 15:50 UTC (7 hours ago)
(HTM) web link (peerj.com)
(TXT) w3m dump (peerj.com)
| michalrichards9 wrote:
| The statistics in this paper are... not robust IMHO. They do so
| many comparisons between the groups and never mention any
| multiple comparisons correction.
|
| Interesting idea, I am not convinced right now - but let's see if
| it reproduces.
| lupire wrote:
| It may be more likely to reproduce if it gets infected with
| toxoplasma.
| Quixotica1 wrote:
| Well said, lol
| lupire wrote:
| Even _suggesting_ that facial assymetry in adults, which takes
| decades to develop, is reduced by a parasite, is an extremely
| extraordinary claim, that requires far more evidence than this.
|
| What plausible mechanism is there for the body to even detect
| asymmetry and then change it? Your brain can't make your ear move
| lower.
| mrfusion wrote:
| Toxoplasma are kinda like the Gould. Can they help us heal too?
| rdevsrex wrote:
| I believe it's spelled Goa'uld :) Who knows, but the very fact
| that a parasite can co-opt our sense of smell to make cat urine
| smell not as bad, is saying something.
| ben_w wrote:
| I also assume that's what mrfusion meant, but there is also
| Sabine Baring-Gould who wrote (among other works) "The Book
| of Were-Wolves", which is clearly relevant to the topic of
| mysterious healing powers:
|
| https://en.m.wikisource.org/wiki/The_Book_of_Were-Wolves
| marcodiego wrote:
| "we found that infected men had lower facial fluctuating
| asymmetry whereas infected women had lower body mass, lower body
| mass index, a tendency for lower facial fluctuating asymmetry,
| higher self-perceived attractiveness, and a higher number of
| sexual partners than non-infected ones. Then, we found that
| infected men and women were rated as more attractive and
| healthier than non-infected ones."
| freddealmeida wrote:
| It is clear that parasites do change our genome and how we
| express our genes in order to further transmit themselves. It
| would not be surprising that good looks, lower body fat, etc
| increases sexual contact and therefor transmission.
|
| New sexual strategies are need I suppose.
| nootropicat wrote:
| >t. toxoplasma gondii
| dsign wrote:
| Well, I for one believe and amuse myself with the findings of
| this paper. It reminds us that nature is not a divinity of
| perfection working in our favor (if anybody had any doubt at this
| point, that is).
| [deleted]
| kwatsonafter wrote:
| Man that's some fucked up shit. I'd bet you'll see Kardash-clone
| ladies putting catshit flakes on their cereal to get, "lean'd." I
| think it's important to note the apostrophe, "d."
| auntienomen wrote:
| Of course they are! They have a kitty!
| tornato7 wrote:
| So people with cats are happier and take better care of
| themselves
| collegeburner wrote:
| Don't let the incels get ahold of this, they'll be eating cat
| poop by the bucketful.
| pengaru wrote:
| Isn't it already understood that toxoplasmosis increases risk-
| taking behavior?
|
| More sexual mates is riskier, living athletic/outdoorsy/"active"
| lives is also more risky than being a couch potato...
|
| I don't think we're breaking new ground in saying the risk-averse
| tend to be less sexually attractive.
| adhesive_wombat wrote:
| First we had Botox, but how long until you can have Toxtox and
| have someone inject protozoa into your face in their living room?
| abeppu wrote:
| From a quick skim, it looks like they don't present anything
| which would distinguish which way the causal arrow points. Do the
| parasites make their hosts more attractive so they are more
| likely to be passed on, or do more attractive people have more
| sex that gives them opportunities to be infected?
| layer8 wrote:
| Or maybe the more attractive people are just more attractive to
| T. Gondii.
| holub008 wrote:
| Seriously, has the bar sunk this low? I was certain the authors
| would express caution in interpreting causality, but alas: "Our
| results suggest that some sexually transmitted parasites, such
| as T. gondii, may produce changes in the appearance and
| behavior of the human host".
| folli wrote:
| T. gondii is not a sexually transmitted parasite. Or am I
| missing something?
| holub008 wrote:
| I was directly quoting the article and am not a domain
| expert. It is interesting to see some commenters here state
| that it isn't an STD. It appears this is an open question.
|
| https://academic.oup.com/aje/article/190/3/386/5905708
| https://pubmed.ncbi.nlm.nih.gov/24986706/
| lupire wrote:
| > may
|
| That _is_ expressing caution.
| holub008 wrote:
| Perhaps it's because I don't frequent the literature, but I
| interpret that as "T Gondii. may [provided by our level of
| statistical certainty in MANCOVA] produce changes".
| Otherwise, what's the point of performing a statistical
| analysis? Moreover what's the value of any assertion if it
| can be guarded by an unbounded-uncertainty keyword "may".
| ascar wrote:
| I think that's a classic case of reading between the
| lines and making implications where one shouldn't. If I'm
| using words that state uncertainty, it is because I am
| not certain, but only say it is a possibility. A research
| result that shows there is a correlation is already
| interesting without establishing or confirming causation.
| Their wording is exactly saying that. Without that paper
| we wouldn't even know there is a correlation!
|
| How else would you like them to state that without being
| overly verbose?
| holub008 wrote:
| > How else would you like them to state that without
| being overly verbose?
|
| "Our results suggest that some sexually transmitted
| parasites, such as T. gondii, may be correlated with
| appearance and behavior of the human host."
|
| I appreciate your viewpoint. I would counter it by saying
| that there are two sources of uncertainty here: choice of
| model & sampling variance. It's my opinion that in
| scientific writing, one should be precise with which
| source of uncertainty they are guarding. If I'm allowed
| to group these together, why can't I make a similar
| statement of causation of any old spurious correlation -
| when obviously my model is bad?
|
| Considering this example again - isn't it arbitrary that
| the authors get to choose which hypothesis (among many,
| like attractive people being predisposed to own cats)
| they get to claim "may" be demonstrated?
|
| Similar line of discussion: https://statmodeling.stat.col
| umbia.edu/2015/04/04/thinking-p...
| ascar wrote:
| > "Our results suggest that some sexually transmitted
| parasites, such as T. gondii, may be correlated with
| appearance and behavior of the human host."
|
| But that is a different statement. They say that they
| found correlation and there may be causation. You say
| there may be correlation, a much weaker claim.
|
| > Considering this example again - isn't it arbitrary
| that the authors get to choose which hypothesis (among
| many, like attractive people being predisposed to own
| cats) they get to claim "may" be demonstrated?
|
| Of course it is arbitrary. But that was their hypothesis
| and you have to start with some hypothesis, no? They
| gathered data to establish correlation between the
| infection and attractiveness. They didn't gather data for
| anything else, so I think it's pretty reasonable to say
| we found correlation and further research might be
| interesting to see if there is causation.
|
| Literally the next sentence says "Taken together, these
| results lay the foundation for future research".
|
| If you go beyond the abstract and into the actual
| article, they are pretty careful to just list
| possibilities for the observed correlation. They
| certainly could have stated that it might just be
| spurious correlation there, but I don't blame them too
| much. These articles are supposed to be concise and not
| verbose and especially the abstract is supposed to be as
| concise and short as possible.
|
| I agree with your general premise and the linked article
| though. It should be a given to consider that and ideally
| also state it in the article.
| axlee wrote:
| > Do the parasites make their hosts more attractive so they are
| more likely to be passed on, or do more attractive people have
| more sex that gives them opportunities to be infected?
|
| T. Gondii reproduces in felines, and is transmitted initially
| through their feces to other hosts. Humans catch it most often
| through infected food (meat, vegetables) or liquids (water,
| milk). Humans cannot transmit T. Gondii to other humans, unless
| pregnancies, organ transplants or cannibalism are involved.
|
| So, regardless of how attractive an host is, he won't have more
| or less opportunities to be infected with T. Gondii than anyone
| else. This is not a STD.
|
| Unless there is some sort of correlation between attractiveness
| and eating poorly corked meat.
| abeppu wrote:
| I think the point of the article disagrees with you? Like, to
| my reading, the hypothesis is that T. Gondii should be under
| selective pressure to support its host mating, because that
| aids its spread.
|
| From the background paragraph:
|
| > However, if parasites diminish a host's health and
| attractiveness to such an extent that finding a mate becomes
| almost impossible, the parasite would decrease its odds of
| reproducing and passing to the next generation. There is
| evidence that Toxoplasma gondii (T. gondii) manipulates
| phenotypic characteristics of its intermediate hosts to
| increase its spread.
|
| And the conclusions paragraph:
|
| > Our results suggest that some sexually transmitted
| parasites, such as T. gondii, may produce changes in the
| appearance and behavior of the human host, either as a by-
| product of the infection or as the result of the manipulation
| of the parasite to increase its spread to new hosts. Taken
| together, these results lay the foundation for future
| research on the manipulation of the human host by sexually
| transmitted pathogens and parasites.
|
| It's hard to read that as anything other than the authors
| classifiying T. gondii as a "sexually transmitted parasite".
|
| I don't know how to reconcile that with what you're saying.
| Am I missing something?
| wzdd wrote:
| Contrary to what you wrote about T. gondii definitively not
| being sexually transmitted between humans, the article links
| to several studies which postulate exactly that. The
| paragraph is:
|
| > Since reports that T. gondii can be a sexually transmitted
| parasite in humans are relatively recent (e.g., Flegr,
| Klapilova & Kankova, 2014; Hlavacova et al., 2020; Kankova,
| Hlavacova & Flegr, 2020; Tong et al., 2021), many questions
| and hypotheses still need to be properly formulated and
| tested in further studies.
|
| The basis for this theory is that T. gondii cysts have been
| found in human ejaculate, which means it could for example be
| transmitted through oral sex. There does not appear to be any
| conclusive proof that this has happened, but apparently these
| are viable cysts which, if swallowed in any other context,
| would result in infection, so it's plausible.
|
| This non-"pregnancies, organ transplants or cannibalism"
| route is the basis for a lot of this article's theorising
| about T. gondii benefiting from raising its host's likelihood
| of having sex.
| dtgriscom wrote:
| > Humans cannot transmit T. Gondii to other humans, unless
| pregnancies
|
| (phew.. I'm male)
|
| > organ transplants
|
| (none needed yet)
|
| > or cannibalism are involved.
|
| (oh, NO!!!!!)
| holub008 wrote:
| How about correlation between attractiveness and owning cats?
| Attractiveness and having a larger number of partners, which
| increases odds of exposure to cats / T. Gondii? These
| hypotheses seem plausible enough that I believe the authors
| are wrong in claiming causality.
| hunterb123 wrote:
| Unless people are hooking up in barns I don't think
| frequenting partners that own cats would be correlated.
| House cats generally eat kibble, not infected mice.
|
| Even then you'd have to infect yourself with the cat while
| getting together, as humans don't transfer to each other.
|
| Personally I don't think there's any causation here at all
| with attractiveness directly.
|
| It may be correlated with more outdoorsy people, those
| people are probably more attractive on average.
| eurasiantiger wrote:
| Just want to note that kibble is not the best of foods
| for cats, especially not as the only food: it tends to
| cause urinary blockages which are a veterinary emergency.
| holub008 wrote:
| I wasn't implying infection was occurring during sex, but
| rather by being in the environment (many people stay
| around partners for more than sex).
| hunterb123 wrote:
| I wasn't implying that either, indicated by "as humans
| don't transfer to each other."
|
| I painted a scenario where your environment would occur,
| and dispute it by saying those cats in that environment
| generally aren't infected
|
| Unless those attractive people are hanging out in barns
| or patios with outside cats.
|
| Now that could be the case if you go at it from an
| outdoors perspective, outdoorsy people may be more
| attractive on average, and they may encounter infected
| cats more on average.
| mulmen wrote:
| There are house cats all over my neighborhood. I can
| think of four in the area. It's extremely common to have
| an outdoor cat as a pet.
|
| Your characterization of cat ownership is unrealistic.
| hunterb123 wrote:
| Most cat owners I know have inside only cats, as do I. I
| do know of 3 cats that roam my neighborhood, they could
| be from quite far away as outdoor cats have a large
| range.
|
| I guess anecdotes from you or I isn't really telling if
| an indoor or outdoor majority of cat ownership is
| "unrealistic". Maybe we need a study :p
|
| Do outside cat owners generally let their cats inside
| their home?
| mulmen wrote:
| Doesn't matter, they're domestic cats and you already
| explained a circumstance where they could expose visitors
| and owners. Half the year here is a hospitable climate
| for outdoor recreation and cat survival. Half of it
| isn't. I have seen these cats for multiple years so
| unless they have an outdoor cat house (something I have
| never seen in my life) then I suspect they come inside.
|
| The ratio of cat owners with outdoor cats is irrelevant.
| They exist and they are common. That's enough to sink
| your assertions.
| hunterb123 wrote:
| > Doesn't matter, they're domestic cats and you already
| explained a circumstance where they could expose visitors
| and owners
|
| > The ratio of cat owners with outdoor cats is
| irrelevant.
|
| It's extremely relevant when talking about a large enough
| scale of infection to support the attractiveness
| causation hypothesis posed by GP.
|
| > I have seen these cats for multiple years so unless
| they have an outdoor cat house (something I have never
| seen in my life)
|
| Outdoor cats generally stay underneath the house /
| porches, cars, etc. during cold or especially hot
| weather.
|
| > That's enough to sink your assertions.
|
| I'm disputing the above proposed hypothesis on the
| grounds I don't think it's common enough occurrence and
| we're lacking information.
| jjj123 wrote:
| I don't understand why you keep mentioning hooking up,
| that seems irrelevant since it's been clarified this is
| not an STD. The parent comment was saying people who own
| cats could be more attractive on average, and people who
| own cats are more likely to get toxoplasmosis.
| hunterb123 wrote:
| > Attractiveness and having a larger number of partners,
| which increases odds of exposure to cats
|
| Hooking up was simply an example of why the person would
| be at the other person's environment.
|
| Replace it with getting together if you're getting hung
| up on it. Whether or not the humans met up to have sex,
| talk, stand on their head, or whatever is irrelevant.
|
| The point was house cats generally don't eat infected
| mice, if you're hanging out in barns or on the patio with
| outside cats, sure maybe.
| atty wrote:
| Agreed. I think it's far more likely that the lifestyle
| differences between more and less attractive individuals is
| causing increased exposure. Not to mention they performed a LOT
| of tests without correcting for multiple comparisons (as far as
| I could tell by skimming). Overall pretty disappointing.
| riccardopa wrote:
| N=35,178. Give us a break, its too small of a study to make any
| conclusion.
| jsnodlin wrote:
| tokai wrote:
| Jokes on you, nothing is concluded.
|
| "Our results suggest [...] these results lay the foundation for
| future research"
|
| Its the classic do an easy little study, and suggest that the
| potential for _results_ might point to further studies. Now you
| have something to tell your research coordinator next time they
| get in your hair.
| hombre_fatal wrote:
| We should just have an HN bot that posts these comments if
| N<1000 or paper.includes(/rats|mice/) for people to upvote.
| carabiner wrote:
| Wait until HNers find out that n = 10 can be more
| significant than n = 100 via power analysis.
| hex4def6 wrote:
| Are toxoplasma-infected scientists more likely to shill for Big
| Toxoplasma?
| bee_rider wrote:
| Note that the 35,178 in this comment is actually a list, aka in
| python: [35, 178], and not the number 35,178 -- which would of
| course be a large enough sample size to make some observations.
| mrfusion wrote:
| /s?
| _nhynes wrote:
| 35 infected, 178 uninfected. The comma is misleading. A slash
| or semicolon might be better.
| netizen-936824 wrote:
| Its more than misleading
|
| There's no space after the comma and the commenter is
| putting two values in a single variable which normal holds
| an integer
| [deleted]
| callesgg wrote:
| Being infected with toxoplasma is know to increase reckless
| behaviour. Having sex with lots of people can be seen as reckless
| behaviour. Using that argument the conclusion is somewhat
| reasonable.
|
| Another one I have thought about is HPV virus(or other sexualy
| transmitted illnesses) and your desire to have sex. There should
| be a strong evolutionary pressure for the virus to increase your
| sex drive. If it does, I don't know.
| sometimeshuman wrote:
| Recklessness in men, is, by its very nature, sexy[0]. Whether
| toxoplasma became genetically lucky (i.e., trait that is
| immediately genetically stable after a few mutations) or if
| evolutionary pressure created this effect (i.e., many
| generations where this trait grows over time) may be impossible
| to ever know.
|
| Edit: Downvotes, again? Added a reference. A scientific claim
| about evolutionary psychology can have merit even if it doesn't
| fit your personal hopes for the human race. Furthermore, in
| what world do the downvoters live where women are more likely
| to causally sleep with the cautious inconspicuous male vs the
| reckless bad-boy.
|
| [0] https://www.thetimes.co.uk/article/reckless-men-are-more-
| lik...
| pessimizer wrote:
| The referenced study is weird[0]. It uses smoking and
| drinking as a proxy for recklessness in men, but doesn't seem
| to take into account at all whether the women who were
| evaluating the men smoked or drank themselves. It's like it
| forgot it was specifically about smoking and drinking, not
| recklessness.
|
| Smoking and drinking women young women (<30) would
| intuitively find smoking and drinking men more attractive for
| a short term thing, and find that behavior less acceptable
| for the long term as they probably find it less acceptable
| for _themselves_ in the long term. Somebody else did this
| analysis with smokers, but didn 't treat the women as
| fungible[1]. They found the heightened attraction to smokers
| _was limited to smokers._
|
| IMO, we don't really need explanation for why reckless (i.e.
| brave, risky decisionmaking) people have more short-term
| relationships. They're more willing to proposition people
| (brave), and more willing to sleep with people who they will
| ultimately decide they actually don't like (risky
| decisionmaking.) This is by definition, as valid if not more
| than the use smoking and drinking as a definitive sign or
| recklessness.
|
| I'm not saying that people who smoke and drink are more
| likely to make brave and risky decisions when it comes to
| interactions with potential sexual partners, but both sets of
| behaviors can be called "reckless."
|
| > in what world [are] women are more likely to causally sleep
| with the cautious inconspicuous male vs the reckless bad-boy.
|
| The world in which the cautious inconspicuous male approached
| her, and the reckless bad boy didn't. Reckless behavior in
| women is also attractive, but it isn't due to conforming to
| some chad stereotype; it's due to the fact that if a woman
| makes bad decisions, sleeping with you might be one of them.
|
| [0] https://journals.sagepub.com/doi/full/10.1177/14747049166
| 316...
|
| [1] https://www.researchgate.net/publication/263849372_Can_ci
| gar...
| callesgg wrote:
| Well, you wrote by its very nature.
|
| For something to be of its very nature it has to be part of
| that thing.
|
| No reference in the world can make one thing in to another.
| stuckinhell wrote:
| https://www.smithsonianmag.com/science-nature/the-parasite-t...
|
| This parasite alters sexual behavior in rats, could this be
| altering people's behavior not just their appearance as well?!
| lupire wrote:
| Yes, that's _why_ the OP study was done. Toxoplasma has long
| been theorized to be a factor in "cat lady" stereotypical
| behavior.
| collegeburner wrote:
| Cat lady stereotype runs the other way in attractiveness,
| counter to the hypothesis formulation.
| lupire wrote:
| OP study is about facial physical attractiveness, not
| lifestyle attractiveness.
| xbar wrote:
| My anecdotal experience is contrary to the science.
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