What does "bubble" mean in the passage? (Reading: Anthropologists tell us that each of us walks around inside "bubbles of personal space." The size of the bubble represents our personal territory, territorial imperative, or "personal buffer zone." We neither like nor tolerate it when someone invades our bubble. As we travel to different places around the world, we learn that some cultural bubbles are larger or smaller than others. The American "bubble" extends about 12 to 15 inches, and so we may stand a combined 24 to 30 inches apart. Scientists point out this just happens to be an arm's length away. One could stretch out his arm and put his thumb in the other person's ear. Orientals, and especially the Japanese, stand even farther apart, anthropologist George Renwick adds. When it comes to ordinary business or social situations, they have the largest bubbles of all. However, in their own public settings, where crowding is impossible to avoid, they accept body contact or just seem to ignore it, "touching without feeling." Latins and Middle Easterners, on the other hand, stand much closer than Americans. They may stand, literally, toe-to-toe. They may even place a hand on the other's forearm or elbow, or even finger the lapel of the other person. However, touch codes are changing all over the world. In the United States, politicians have learned the value of touch. They frequently give two-handed handshakes, casually touch the elbow of another, or lightly touch the back of the person standing next to them. "Pressing flesh" has become a byword on political campaigns. Also, Japanese managers posted in the U.S. factories are steeling themselves and learning to accept finger-crunching handshakes, back patting, and maybe even a friendly arm around the shoulders for the softball team photo.)