Its already known that past experiments with rodents are problematic. A number of studies could not be repeated, and it took a while before they twigged that it

Its already known that past experiments with rodents are problematic. A number of studies could not be repeated, and it took a while before they twigged that it was the higher proportion of female scientists. The rationale in the article I read was that the rats were more stressed when the males were around, and disguising the smell mitigated it like they found in this new study. Another similar problem was mice in maze experiments, which also could not be repeated. The experimenters were using mazes with sand on the floor rather than hard bases, and it turned out that the earlier experiments were not measuring the memories of mice; instead their ability to sense vibrations from their footsteps and helped with location senses.