Parasites Makes Us Dumber or Sexier

odie_q writes "It has long been known that the Toxoplasma gondii parasite alters its host's behavior, but now it seems the way it alters it depends on the sex of the host. From the article: 'A common parasite can increase a women's attractiveness to the opposite sex but also make men more stupid, an Australian researcher says ... Infected men have lower IQs, achieve a lower level of education and have shorter attention spans. They are also more likely to break rules and take risks, be more independent, more anti-social, suspicious, jealous and morose, and are deemed less attractive to women. On the other hand, infected women tend to be more outgoing, friendly, more promiscuous, and are considered more attractive to men compared with non-infected controls.'"

Comments

Ahh Toxoplasma gondii

[GrumpySimon]

I believe this is one of those news stories that sits around waiting for a slow news day. The original paper was released in November. It's written by Kevin Lafferty and was published in Proc. Roy. Soc. B.

It's a really quite fascinating paper - I recommend tracking it down if you can get access. Here's how it goes: Toxoplasmia gondii is adapated to live in cats and reproduces in felid intestinal cells & is shed, encysted, in their feaces. Then it can directly infect cats who come into contact with the cysts, or it encysts in brains of smaller mammals, and moves up the food chain as they get eaten until it hits a cat, and can reproduce again.

Fascinatingly, T.g. appears to affect rodent behavior to increase predation risk - i.e. the rodents become more active, less fearful of cat/cat smells, and have increased dopamine levels (which supposedly leads to novelty seeking behavior and neuroticism-type behaviors, or at least, they do in humans).

Despite humans not having any major cat predators, it could still affect us as a byproduct type of thing. Particularly that whole dopamine increase - this is should increase neuroticism levels.

So - the big question - does prevalence of T.g. correlate with cultural variation in neuroticism in humans? Lafferty finds a fairly strong correlation ( r2 of 0.38 ) between population aggregate neuroticism (as measured by the fairly standard NEO PI-R personality inventory ).

Unfortunately I think the populations he uses for his stats are a little bit suspect (always the problem with worldwide analyses though), but it's definitely worth a read. You should also keep in mind that so far it's only an interesting correlation and not a direct demonstration that T.g. causes large scale cultural differences.