Takagi’s team recruited 48 cats for their experiment. Of these felines, 19 lived in households with other cats. The rest were residents of cat cafés—establishments popular in Japan—where customers can interact with a whole group of kitties who are sometimes available for adoption. The researchers wanted to compare cats from these environments because “we thought there might be a difference in the number of times a cat is called by name at a home compared to at a cat café,” says Takagi. Café cats spend a lot of time with visitors who might not know them well, so these cats may have fewer opportunities to hear their companions’ names.
The scientists recorded the voices of owners and café caretakers calling out their cats’ names. They also took photos of each cat’s face. For the experiment, a researcher gently held a feline subject, or study participant, in place in front of a laptop. The scientists played an audio recording of the owner or caretaker calling the name of another cat who lives with the subject. Then a photo of a cat’s face appeared on the screen for seven seconds. Sometimes the photo matched the name the subject had just heard, and sometimes it didn’t. The researchers timed how long each cat looked at the photo (see Names and Faces).