What does global communication look like? One way to picture it is by mapping phone calls—specifically where they're coming from and heading to. The map below, first flagged by my colleague Tim Fernholz at Quartz, shows a year's worth of cross-border calls, as measured in minutes per person spent on international phone calls in 2012, the most recent year for which data is available. It's one component of a study, written by business scholars Pankaj Ghemawat and Steven A. Altman, with funding from the logistics firm DHL, that aims to quantify globalization by tallying up measures of "cross-border flows of trade, capital, information, and people."

A map of phone calls around the world. Click here for a full-sized version. (DHL Global Interconnectedness Index 2014)

The phone data is part of a broader measure of how information moves across the world, and the report's authors explain what may be driving the direction of the lines. One set of factors is the cost of an international phone call—which the authors note is relatively low in the United States, for example—and the income available to pay for it. People in rich countries are far more likely to call overseas than people in poorer countries. Among total international phone calls, according to the study, 41 percent are placed from advanced economies to emerging economies; just 9 percent go in the other direction.

“The other, more evident driver of calling patterns has to do with interactions due to immigrants," the researchers write. "The top two destinations of international calls placed from the United States are Mexico (the largest source of first-generation immigrants) and India (the third-largest)." The same kind of pattern appears elsewhere: "[T]he two flows of the largest 10 that don’t involve the United States are from Hong Kong to China and from the United Kingdom to India (the largest source of first-generation immigrants to the United Kingdom).”

The map appears to depict an interconnected world, albeit one in which the main source of international interaction occurs within rather than between regions. But the map doesn't reveal just how rare overseas calling actually is. People in the U.S. may check on relatives overseas from time to time, but they still do most of their calling in-country. Of all the minutes people spend on the phone every year, the authors write, only about 3 to 4 percent are devoted to international phone calls. “The average person," they note, "still transmits and receives a very limited amount of information via international telephone calls: just about 2.5 hours of conversation content per year!”

You could draw the conclusion that the phone is not the preferred mode of international communication, and you’d be right—up to a point. The map does not include computer-to-computer calls, for instance via Skype, which, as the authors write, “accounted for about one quarter of all international calling minutes” in 2012. Meanwhile, they also note that the share of Internet traffic that crosses borders is, at 17 percent of total Internet traffic, about five times as high as the percentage of total phone calls that are international. But that's not exactly a cyberspace without borders. "[A]n estimated 16% of people's friends on Facebook are foreign, as are 25% of the people individuals follow on Twitter," the write. "Just because we are able to befriend anyone living anywhere on Facebook doesn't mean we will—there is an important distinction between potential connectivity and actual connectedness."

None of which excuses you from calling your folks every once in awhile, wherever they may be.