A lazy error [0] in the abstract suggests that the paper may have been written by a domestic cat (Felis catus). Given that male experimenters tend to stress out mice [1], it is plausible that the opposite effect occurs in cats. Mostly, it would be fun to know whether cat greetings reflect different motivational or emotional states, since reasonable people might believe that they don't.

[0] "We also tested whether demographic factors such as the influenced the amount of greeting behavior expressed by household cats."

[1] https://www.nature.com/articles/nature.2014.15106