Last week, a study published in Nature revealed that lab mice react differently to their male and female researchers:
Mice, and rats, it turned out, are made especially stressed out by men. One way to watch the rising anxiety and depression of a mouse is to force it to swim. “Mice can swim very well, and they can swim for a long time, but they don’t really like it,” [psychologist Robert] Sorge said. Over a series of experiments, the team determined that even if a female scientist is working with a mouse, “just having a man in a room was similar to three minutes of forced swim.” …
The team determined that the rodents were responding to the scent of men, not the sight. … To confirm the smell theory, Sorge went on, “we’d have the man wear a T-shirt overnight in bed, with no cologne or anything. We’d have him take the shirt, put it in a bag, and drape it over a chair.” Sorge couldn’t detect the smell, though others in the lab could; the stink depends on the dose, he explained.
The team conducted the same musk test with other males—guinea pigs and cats and dogs, fixed and unfixed. (All male mammals, including humans, produce testosterone.) “We just used the bedding,” Sorge said. He brought in the pillow that his daughter’s cat sleeps on. In each case, the masculine scent provoked the same response from the mice. And it wasn’t just the introduction of a strong odor: “We tried vanilla smell. We tried banana—none of them did anything. It didn’t have to do with being a novel smell. It had to do with a testosterone smell.”
Ian Steadman suggests next steps for scientists:
Scientists working with rodents will need to begin acknowledging and studying these further biases that their implicit assumptions introduce to each experiment, or there may be huge bodies of potential knowledge out there that we just will never know. At the very least, scientists could begin reporting the genders of those taking part in experiments with mice subjects, to address the problem of men ruining things with their presence.
The Dish 