Cats have very sensitive ears and often respond to the presence of potential prey that they can hear but cannot see. In previous studies, cats have been shown to make mental representations of items that they have seen, but that subsequently disappear from sight. These tests of object permanence always present subjects with visual information, and have never investigated a cat’s ability to track the whereabouts of another individual through the use of vocalizations.
In a recent study by Japanese researchers, domestic cats were presented with auditory cues that came from their owner’s voice, from a familiar cat, or from a non-social source such as electronic sounds. Initially, the cats were habituated to the sound while it was played five times from a nearby speaker (speaker A).
After initial habituation, the cats were exposed to one of four different experimental conditions: they were presented with the same sound from the same location, the same sound from a different location (speaker B, more than 4 m away), a different sound from the same location or a different sound from a different location (speaker B). The behavioral responses to these tests were recorded on video cameras set up in the experimental rooms.
The researchers hypothesized that if a cat identifies a familiar individual (owner or familiar cat) from a vocalization and mentally maps the location of this familiar individual, then it should be “surprised” when the same vocalization is subsequently heard from a different location. This would simulate an “impossible teleportation” of the owner or familiar cat. If cats are not forming cognitive representations of the locality of the owner or other cat in this way, then they will not be surprised when the locality of the individual apparently changes.
The behavioral outcome of “surprise” was assessed by independent raters who watched the video footage recorded during each trial. They rated each cat’s surprise response by assessing a combination of behaviors, including moving ears, changing head direction, looking back towards speaker A (the initial source of the sound), and moving around the room.
The results showed that cats were most surprised when their owner’s voice was first heard from one locality (speaker A), and then immediately from another locality (speaker B). This indicated that the cats maintained a representation of their unseen owner from his or her voice alone, and expected the owner to be in the location of the most recent vocalization. The cats were surprised by the apparent teleportation of the owner to a new location.
By contrast, cats showed no surprise when a familiar cat was apparently teleported to a new location. They were surprised, however, when hearing the “meow” sound of a different cat from a different location. Cats are solitary organisms that are interested in the presence of other conspecifics mostly in terms of fighting them off their territory or mating with them. This explains the behavioral response under these experimental conditions.
Cats exposed to non-social, electronic sounds registered no surprise at all when the sounds moved inexplicably to a new location.
The findings, published today in the journal PLOS, support the idea that cats mentally map their owner’s location from voice cues and are surprised when the owner turns up inexplicably in a different location. This corresponds with previous studies showing that cats can form mental images of objects that they have seen but subsequently become hidden from them.
The study authors conclude that forming mental representations of the outside world, and then manipulating those representations flexibly, is an important feature of complex thinking and a fundamental aspect of cognition. They state that continuing comparative research on this ability can help shed light on how intelligence has evolved in various species, and the potential influence of ecological factors.