Cats distinguish between speech directed at them and humans, study finds

Human tone is known to vary depending on who the speech is directed to, such as when talking to infants and dogs. The tone of human speech has been shown in previous studies to change when directed at cats, but less is known about how cats react to this.

Charlotte de Mouzon and colleagues from Université Paris Nanterre (Nanterre, France) investigated how 16 cats reacted to pre-recorded voices from both their owner and that of a stranger when saying phrases in cat-directed and human adult-directed tones.

The authors investigated three conditions, with the first condition changing the voice of the speaker from a stranger's voice to the cat's owner. The second and third conditions changed the tone used (cat-directed or adult-directed) for the cat's owner or a stranger's voice, respectively. The authors recorded and rated the behaviour intensity of cats reacting to the audio, checking for behaviours such as resting, ear moving, pupil dilation, and tail moving, amongst others.

In the first condition, 10 out of the 16 cats showed a decrease in behaviour intensity as they heard three audio clips of a stranger's voice calling them by their name. However, when hearing their owner's voice their behaviour intensity significantly increased again. The cats displayed behaviours such as turning their ears to the speakers, increased movement around the room, and pupil dilation when hearing their owners' voice. The authors suggest that the sudden rebound in behaviour indicates that cats could discriminate their owner's voice from that of a stranger.

In the second condition, 10 cats (8 of which were the same from the first condition) decreased their behaviour as they heard audio from their owner in an adult-directed tone but significantly increased their behaviour when hearing the cat-directed tone from their owner. The change in behaviour intensity was not found in the third condition when a stranger was speaking in an adult-directed and cat-directed tone.

The authors observed that the cats can distinguish when their owner is talking in a cat-directed tone compared to an adult-directed tone, but did not react any differently when a stranger changes tone.

The small sample size used in this study may not represent all cat behaviour but the authors propose that future research could investigate if their findings can be replicated in more socialised cats that are used to interacting with strangers.

The authors suggest that their findings bring a new dimension to cat-human relationships, with cat communication potentially relying on experience of the speaker's voice. They conclude that one-to-one relationships are important for cats and humans to form strong bonds.