Betteridge’s law of headlines would suggest that the answer is “no”, but the authors of a new paper in Animal Cognition beg to disagree. This short report (reference and free pdf below) tests the idea that cats can identify a rattling sound in a box as denoting an object in the box, and then, when the box is opened upside down, will get flummoxed if something doesn’t drop out of the rattling box. They will also get flummoxed if a toy drops out of a shaken box that didn’t make a rattle. In other words, cats can somehow sense the incongruity between an auditory stimulus (the rattling) and a visual stimulus (the expected object causing the rattle).
So, to be brief, here’s what Saho Takagi and her colleagues did. They studied 30 domestic cats of both sexes, all tested in —yes—cat cafes: a delightful staple of Japanese culture. Each cat was given four tests involving a box and a putative object. The box was designed with an electromagnet and all of them held three metal balls, with the magnet activated by pushing a button on the box. When the balls were in the box, shaking it would make a rattling sound—unless the balls were affixed to the electromagnet.
The kicker is that the electromagnet not only did the electromagnet allow a box to contain an object without making a rattling sound when shaken, but also enabled the investigator, when the bottom of the box was opened, to either release the ball to drop on a cushion, or keep the ball inside the box, stuck to the electromagnet.
Each cat was thus exposed to four conditions:
- Box rattles, cat hears it, then box opened and balls drop out.
- Box rattles, cat hears it, then box opened but NO balls drop out (electromagnet turned on).
- Box does not rattle (though it has balls in it), then box opened and balls drop out
- Box does not rattle (though it has balls in it), then box opened but NO balls drop out (electromagnet activated the whole time).
As the caption above notes, conditions 1 and 4 are congruent with expectations from Cat Physical Law, but conditions 2 and 3 are “incongruous”: the cat either hears an object and perhaps expects it to fall out (but it doesn’t), or doesn’t hear an object and nevertheless sees it fall out. These two conditions should flummox the cat—IF cats can associate an auditory stimulus with the appearance of an object they haven’t yet seen.
The researchers made two predictions. The first one, which is not surprising, is that cats would spend a larger amount of time looking at a box that’s rattling before the object either does or doesn’t drop out. This was verified by the data below (“mean looking time” is the number of frames of the videotape that the cat looked at the box during the five-second shaking period; these frames were scored by observers who were blinded as to the condition). Whether or not an object was going to drop out of the box (“object” or “no object”), cats paid significantly more attention to the box that rattled. No surprise here:
But then the cats got the chance to be flummoxed: the boxes were opened, and the ball either did or didn’t drop out. After 5 seconds of holding the box upside down, it was placed on the floor for 15 seconds, and the cats were released to look at the apparatus for a 15-second inspection period (they were held by their owners during the shaking phase and five-second post-opening phase). The authors predicted that cats would look at the box longer under the two “incongruent” conditions (2 and 3 above) than under the congruent conditions, because they’d be flummoxed by the lack of a visual stimulus matching the auditory one. And that, in general, is what they found (again, the length of inspection was judged by the number of frames of the videotape during which the cat was looking at the box:
As the graph shows, cats looked the longest at the box when an object fell out but there was no sound, or when there was a sound but no object fell out, than under the other two conditions taken together. (Whether an object fell out also in general increased their inspection time). The comparisons above are statistically significantly different when connected by a bracket with an asterisk. In particular, the authors’ predicted differences in inspection (between sound/object vs. no sound/object, as well as between sound/no object vs. no sound/no object) were upheld. HOWEVER, there was no difference between inspection time for the sound/object vs the sound/no object condition.
The authors interpret this as the cats looking longer at the apparatus when conditions 2 and 3 obtained: those conditions with physical incongruity. This is what they say:
This study may be viewed as evidence for cats’ having a rudimentary understanding of gravity. We have found no study specifically testing knowledge of this fundamental physical rule in cats. Some nonhuman animals have been shown to respond spontaneously in accordance with gravity (e.g., tamarins: Hood et al. 1999; dogs: Osthaus et al. 2003), which suggests that an innate tendency to react in accordance with the gravity rule may be common among mammals.
Well, forget the “understanding of gravity” part, and look at this as cats showing an association between a sound and the expected appearance of an object. The results support this to some extent, but the lack of difference in inspection time between conditions 1 and 2, in which 2 is incongruous and 1 is not, weaken this conclusion somewhat. (To be fair, one might argue that condition 1, in which a rattling box releases a ball, would really interest cats!) The similar results in studies with tamarins and dogs led the authors to suggest that an “understanding of gravity” may be “common among mammals.”
Finally, I’m pleased to see that the first author of the study owns a cat. Here’s a picture of Saho Takagi and her cat. Who else but a cat lover would even do such a study?
Takagi, S. et al 2016. There’s no ball without noise: cats’ prediction of an object from noise. Animal Cognition, 2016; DOI: 10.1007/s10071-016-1001-6