
Can Microbes Encourage Altruism? - tdurden
https://www.quantamagazine.org/can-microbes-encourage-altruism-20170629/
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cronjobber
If _humans_ had parasites that would encourage them to be altruists against
their interest and for the sole benefit of their parasites—which is of course
implausible and hypothetical and absolutely not even possible—would they make
us downvote and flag comments on HN discussing the possibility of parasites
manipulating humans to be altruists against their interest?

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ianai
The popularity of cats on the internet is at odds with your premise. They've
clearly infected many humans with thought changing microbes and yet
^H^H^H^H^H^H^H^H^H...what were we talking about?

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Poodlemastah
Uhm, just saying, you guys ever heard of toxoplasmosis?

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Terr_
Now I'm thinking of an old short story titled "The Giving Plague", by David
Brin.

[http://www.davidbrin.com/fiction/givingplague.html](http://www.davidbrin.com/fiction/givingplague.html)

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plaguuuuuu
>The researchers then pitted two types of virtual microbes against each other
in the simulation. One microbe promoted altruism in its hosts, while the
second did not.

Replace microbes with anything that's heritable and the effect still plays out
in the simulation. With respect to the study's model, is there any difference
at all between bug heredity and DNA?

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yorwba
The study is here:

[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5241693/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5241693/)

Their model has altruistic _α_ and non-altruistic _β_ microbes, that determine
the behavior of their hosts. In each generation, hosts are paired up randomly
to interact. Altruistic hosts reduce their fitness by a certain cost _c_ and
increase their partner's fitness by a benefit _b_. Additionally, each kind of
microbe has the opportunity to infect the other host with transmission
probability _Tα|Tβ_.

The proportion of α microbes increases when _Tα b > c (1 - Tβ) + (Tβ - Tα)_

Importantly, when there is no horizontal spreading between hosts (Tα = 0),
this is never true, so simple heritable genes are not enough for altruism to
dominate.

The quantity _Tα b_ essentially corresponds to the benefit accrued by
spreading to a host you have helped before, _c (1 - Tβ)_ is the cost you have
to bear if your host is not taken over by β anyway, and _(Tβ - Tα)_ is the
natural advantage of β over α.

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yakult
There's this, there's the post the other day about encouraging 'openness' with
MDMA, there was the article proposing 'fairer' jerrymandering reform that just
so happens to shift all the votes in a single direction, plus all the
hagiographies of our tireless selfless social media censors, I'm beginning to
think there's a burgeoning industry working on novel side-channel attack
against the electoral system.

