To do that, the researchers studied 30 domesticated cats, and videotaped their reactions to different scenarios. If you’ve ever had a cat, you’ve probably watched them react excitedly to a shaken bag of treats. The researchers in Japan have created a similar scenario by shaking a container in front of the cats. In one scenario, the container rattles and then an object is dropped from the container. In another, the container makes no noise and no object drops. These two are generally congruent with the laws of physics: the sound signals to the cat that there is something inside. And the cats reacted appropriately, staring longer at the container that made a sound.