Last week’s Science Times carried an article explaining why the Ju/’hoansi are so enthusiastic about giving gifts. It’s a question of survival.

A New York Times reporter interviewed Pauline (Polly) Wiessner, an anthropology professor at the University of Utah, whose published scholarship has included works on gift giving in the Kalahari. Wiessner maintains that Ju/’hoansi social relationships work much like insurance does in America: to provide support during emergency situations.

The Ju/’hoansi gift giving is an important way for them to build relationships with other people. When they face a decrease in natural foods, they can call on their long-existing friendships and move to areas where their contacts live—and thus have access to more abundant food. Wiessner calls the Ju/’hoansi approach a “system maintained through gift-giving, storytelling and visiting.”

She gives an example that occurred during the first year she was in the Kalahari, in the early 1970s. She witnessed a period when the band she was studying experienced some food shortages—desert plants died and game dispersed. People began to talk fondly about friends living up to 200 km away. They started making beautiful objects for their friends, and when conditions got bad enough, about 150 people trekked to the camps of the folks they were thinking about. They continued the visiting until conditions in their home territories began to improve.

Telling stories is their way of keeping memories of distant people fresh, and their gifts signal their fondness for others. They visit other people often, not just when conditions are difficult, just to keep up their relationships, which of course work both ways, depending on where scarcity strikes. They exchange gifts frequently to help maintain the relationships.

Wiessner takes her analysis a step farther, however. She argues that these elaborate social relationships, which developed in Africa many millennia ago, allowed humans to move out of the continent and push into new territories around the world. “The storing of relationships for a time when you will need them is what facilitated this expansion,” she said. Beyond that, cultural advances may have also occurred due to this gift-giving. People who became skilled in fabricating nice gifts may have been more successful in building effective social relationships. The genetic propensity to craft better gifts, an essential ingredient for survival, might have been passed along to future generations.

The interviewer asked her if there are contemporary examples of this kind of social networking behavior. She responded that Facebook is a good one. It keeps alive memories of friends from long ago, and allows people to share information and mementos—pictures and reminiscences. Facebook posts represent “a kind of token that says, ‘I’ve kept you in my heart,’” she says.

The article closes with an amusing incident that occurred a few years ago. Some of her Ju/’hoansi friends gained access to a satellite phone from a safari tour operator, and found someone who could operate the device. They called Dr. Wiessner in the middle of the night, Utah time, to ask a favor of her. Another American had promised to buy them some athletic shoes for their soccer team. They asked her if she would buy the shoes, bill him, and bring along the shoes with her the next time she traveled to Namibia.

She told the interviewer that she was not at all annoyed by the call. She had been wondering how they were going to be able to continue to survive in their resettlement camps, where they get less nutrition than they did while they were still hunting and gathering. But the phone call gave her hope. She has more confidence now that they will be able to combine ancient strategies for maintaining their social structures with advanced technologies that will allow them to survive in the modern world.