A scientist working for the US Geological Survey and the CA university system has found out that a parasite commonly acquired by cleaning up after house cats can alter personality on a national level depending on country-wide exposure rates.
“The geographic variation in the latent prevalence of Toxoplasma gondii may explain a substantial proportion of human population differences we see in cultural aspects that relate to ego, money, material possessions, work and rules,” he says in the press release.
Apparently the parasite affects the personality trait of neuroticism. Neurotic people tend to be anxious and moody.
It's a stretch to go from there to "ego, money, material possessions, work, and rules" and the part about it explaining "a substantial portion" of cultural differences really overstates the findings I'd guess.
It all makes me wonder what the published study in the Aug 2, 2006 issue of the Proceedings of the Royal Society actually says.
My libraries only carry the electronic version up until 2000 and the print version won't arrive for several more weeks.... so I guess for now, we'll just have to take his word for it.
It is very interesting though! I love the studies that investigate how parasites manipulate their hosts so they can replicate even more efficiently. Parasite-host co-evolution is definitely one of my favorite evolutionary topics!
Here's an easier to digest version of the press release.