Free will exists, right? We are in control of our own minds and thus our own actions?
That’s what most of us like to believe, but what if a simple parasitic organism robbed us of at least part of that freedom? We know this happens quite regularly in the rest of the animal kingdom. For example:
Consider Polysphincta gutfreundi, a parasitic wasp that grabs hold of an orb spider and attaches a tiny egg to its belly. A wormlike larva emerges from the egg, and then releases chemicals that prompt the spider to abandon weaving its familiar spiral web and instead spin its silk thread into a special pattern that will hold the cocoon in which the larva matures. The “possessed” spider even crochets a specific geometric design in the net, camouflaging the cocoon from the wasp’s predators.
Why shouldn’t it also happen in humans? The possibility that we’re not as free as we thought is gaining credence. One of the first culprits identified is Toxoplasma gondii, a single-celled protozoan found in cat feces, which produces self-destructive behavior in rats:
She quickly confirmed, as previous researchers had shown, that infected rats were more active and less cautious in areas where predators lurk. But then, in a simple, elegant experiment, she and her colleagues demonstrated that the parasite did something much more remarkable. They treated one corner of each rat’s enclosure with the animal’s own odor, a second with water, a third with cat urine, and the last corner with the urine of a rabbit, a creature that does not prey on rodents. “We thought the parasite might reduce the rats’ aversion to cat odor,” she told me. “Not only did it do that, but it actually increased their attraction. They spent more time in the cat-treated areas.” She and other scientists repeated the experiment with the urine of dogs and minks, which also prey on rodents. The effect was so specific to cat urine, she says, that “we call it ‘fatal feline attraction.’”
These same effects are present in humans. In fact, men infected with T. gondii actually find cat urine much more attractive than men who are not infected. But more relevant, rates of schizophrenia and suicide increase with population-wide increase in the prevalence of T. gondii infection. Whether this particular parasite is any real cause for alarm is still up for debate. Jaroslav Flegr, the man conducting many of the studies on T. gondii, thinks his results are more of a curiosity than a cause for alarm.
But if the rest of the animal kingdom is anything to go by, this is certainly not the only organism that might have an effect on our thoughts and actions.
The whole article can be found at the Atlantic, and is definitely worth a read.
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