What’s the News: Infections that change an organism’s personality are a strange little corner of biology, with toxoplasmosis, which brainwashes mice and rats to have no fear of cats, topping the list. But scientists think that more pedestrian infections could play a role in shaping personality, especially when they happen early in life. Ducklings provide the latest data that this theory may have something to it.

How the Heck:

Ducks assess an object’s color when deciding whether it’s safe, showing a noted preference for green and a dislike of orange, which researchers think might indicate that insects of that color can be toxic.
To see whether they could get ducks to branch out, as well as be more active in unfamiliar environments, they first simulated a parasite infection by injecting ducklings at various stages of development with sheep red blood cells, which challenge the immune system in a similar way. (They didn’t infect them with real parasites because they wanted the same level of immune reaction in each duck, and it would require a much larger sample size to average out the varying effects that pathogens have on different individuals.)
Once those ducklings and their uninjected counterparts grew up, ...