Cats have lived alongside humans for around 12,000 years, and during that time, it seems they've been paying close attention to how we communicate.
A new study suggests that our feline companions can even learn to associate the words we use for particular objects or images, and they pick this up faster than our own babies do.
Previous research has shown cats can follow human pointing, they understand who is on their team, who they can trust, and who is in charge of their food. We also know they can recognize their own name.
Cats can even learn the names of familiar cats and people – findings that led cognitive scientist and first author of the new study, Saho Takagi from Abazu University in Japan, to wonder whether they are "hard-wired" to learn human language.
"I was very surprised, because that meant cats were able to eavesdrop on human conversations and understand words without any special reward-based training," Takagi told Christa Lesté-Lasserre from Science.
But it's been unclear whether cats 'learn' other human words in the way dogs can.
So Takagi and her colleagues tested cats' language abilities, with an experimental design that has previously been used to study the development of language in 14-month-old human babies, who showed signs of associating words with objects after just 16 to 20 repetitions.
The team gave the word test to 31 adult pet cats, by putting each one in front of a laptop showing two short cartoon animations, while an audio track of the cat's caregiver saying a made-up word was played.
For the first animation – of a unicorn-like creature growing and shrinking – the cats heard their owner say 'keraru'. And for the second – an expanding and shrinking red-faced sun – the made-up word was 'parumo'.
"In a study of human infants, infants received at least four 20-second trials for a picture-word pair," the authors write.
"Most cats habituated to the stimulus pairing after four trials, which means that they received only 9-second exposures in two trials for each picture-word pair."
When the cats tired of this, they were given a break before the next round, in which the images and audio were played four more times, with a slight tweak: half the images had the 'wrong' audio.
Despite the short habituation time, the cats showed signs of perplexity when they detected a mismatch, spending an average of 33 percent more time looking at the screen when this happened.
These results, the authors write, "demonstrate that cats can rapidly form picture-word association".
"Some cats even gazed at the screen with their pupils dilated during the 'switched' condition," Takagi told Science. "Cats pay attention to what we say in everyday life – and try to understand us – more than we realize."
While these experiments suggest cats might be able to associate human words with pictures even faster than human babies do, there are a few key differences between the 1990s experiment on babies and this new study that mean they can't be compared directly.
The babies, for example, were given only one-syllable words, and they were spoken in a range of intonations by an unfamiliar speaker. The cats, on the other hand, heard three-syllable words spoken by their own caregivers in a somewhat exaggerated manner.
Regardless of who can learn words faster, it's still pretty fascinating that cats can pick up on human word-image associations.
According to the authors, further research into whether these abilities are shared or unique could help us understand cognition and communication across different species.
This research was published in Scientific Reports.