Via Andrew Sullivan, James Hamblin in The Atlantic:
Toxo[plasmosis gondii] has been all over the news in recent years, since it became known that the parasite manipulates people’s behavior. Maybe most interestingly and notoriously, it seems to make men more introverted, suspicious, unattractive to women, and oblivious to the way others see them. Infected women, inversely, have been shown to be more outgoing, trusting, sexually adventurous, attractive to men, and image-conscious. Infected men tend to break more rules than their uninfected peers, and infected women tend to pay them more heed. Infected men and women are 2.5 times more likely to have traffic accidents, more likely to develop schizophrenia, and more likely to engage in self-directed violence.
As these stories made news, though, they lacked a logical explanation. At least 60 million Americans have it, if almost always unknown to them, so understanding this is beyond academic. Thinking about the potential scale of the parasite’s effect on civilization and history can be overwhelming, like imagining the twin brother you never had. If you do have a twin brother in real life, it’s like imagining your triplet. Already have a triplet? You get the idea.
Why, though? Why does Toxo affect human behavior? In The New York Timeslast year, Choire Sicha channeled cats in a memo (“From the desk of: Cats”) that read, “We have trained, by means of this gentle biological warfare, your women to let us into your homes, and your men to stay home and scratch us in our difficult places.”
Who are you going to believe? The cats?
More here.