Alba de xarxes socials

26 01 2012

Antics éssers humans no han tingut el luxe d'actualitzar el seu estatus de Facebook, però les xarxes socials no obstant van ser un component essencial de les seves vides, un nou estudi suggereix.

Conclusions de l'estudi descriure els elements d'estructures de xarxa social que poden haver estat presents des del principi en la història humana, que suggereix com els nostres avantpassats pot han format llaços amb kin i no-kin basat en atributs compartides, incloent-hi la tendència a cooperar. Acord amb el document, xarxes socials contribuït probablement a l'evolució de la cooperació.
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"La cosa sorprenent és que antigues humà les xarxes socials tan molt molt assemblar-se el que veiem avui,", va dir Nicholas Christakis, professor de Sociologia mèdica i medicina a l'escola de Medicina de Harvard i professor de Sociologia a la Facultat d'Harvard d'Arts i Ciències, i autor d'alt nivell en l'estudi. "Des del moment estàvem al voltant de les fogueres i havia paraules flotant a través de l'aire, per avui quan tenim digitals paquets flotant a través de l'èter, hem fet xarxes de bàsicament la mateixa classe."

"Hem trobat que el que estan fent gent moderna amb les xarxes socials en línia és el que hem fet sempre — no només abans de Facebook, però abans de l'agricultura,"estudi coautor, va dir James Fowler, professor de genètica mèdica i Ciències polítiques a la Universitat de Califòrnia, San Diego, qui, amb Christakis, ha estat autor de diversos estudis seminals de l'humà les xarxes socials.

Els resultats es publicaran gener 26 enNatura.

Arrels d'altruisme

El món natural, Red in tooth and claw, té un costat suau. Mentre que els individus ferotgement competir per garantir la proliferació del seu progeny, uns pocs animals, incloent-hi els éssers humans, també cooperar i acte altruista. Researchers have wondered if human social networks are a product of modern lifestyles, or if they could have emerged under the kind of conditions that our distant ancestors faced. This question has been challenging for classic evolutionary theory to explain neatly.

For cooperation to arise, an altruistic act, like sharing food with a non-relative, must have a net benefit for the sharers. En cas contrari, purely self-serving individuals would outcompete and eventually replace the selfless. All theoretical explanations for the evolution of cooperation—kin selection, reciprocal altruism, group selection—rely on the existence of some system that allows cooperators to group together with other individuals who tend to share.

“If you can get cooperators to cluster together in social space, cooperation can evolve,” said Coren Apicella, a post-doctoral research fellow in Health Care Policy at Harvard Medical School and first author on the paper. “Social networks allow this to happen.”

While it is not possible to quiz our distant ancestors about their friendships or habits of sharing and collaborating, a team of researchers from Harvard Medical School, the University of California, San Diego, and the University of Cambridge have characterized the structure of social networks among the Hadza, an ethnic group in the Lake Eyasi region of Tanzania, one of the last surviving groups of hunter gathers. (There are less than 1,000 Hadza left who live in the traditional way).

Getting connected

The Hadza lifestyle predates the invention of agriculture. The Hadza eat a wide range of wild foods, foraging for tubers, nuts, and fruit and hunting a great variety of animals, including flamingos, shrews, and giraffes. Honey is one of their favorite foods, known by half a dozen different names in Hadzane, their primary language.

Apicella took the lead in collecting the data for the study, interviewing 205 adult Hadza over the course two months, measuring their tendency to cooperate and mapping their friendships.

Apicella, Fowler and Christakis designed the study and experiments, working with Frank Marlowe, lecturer in the Department of Archaeology and Anthropology of the University of Cambridge, and author of the only book-length ethnography on the Hadza in English.

Collecting the data was not easy. The nomadic Hadza roam over 4,000 rugged square kilometers. Apicella and her research assistants travelled the region by Land Cruiser battling mud-drenched trails—at one point forcing her and her colleagues to pave the ground with felled trees—and, on an earlier trip, even fleeing a horde of marauding elephants.

In order to construct a social network, Apicella and her colleagues took a dual approach.  First, they asked Hadza adults to identify individuals they would prefer to live with in their next encampment. Second, they gave each adult three straws of honey and were told they could give these straws as gifts to anyone in their camp. This generated 1,263 campmate ties and 426 gift ties.

In a separate activity, the researchers measured levels of cooperation by giving the Hadza additional honey straws that they could either keep for themselves or donate to the group.

When the networks were mapped and analyzed, the researchers found that co-operators and non-cooperators formed distinct clusters.

The researchers also measured the connectedness of people with similar height, age, handgrip strength, etc., and other characteristics, such as food preference. They also analyzed the transitivity of friendship—the likelihood that one’s friends are friends with one another, and other network properties.

The structure and dynamics of the Hadza hunter-gatherer social networks were essentially indistinguishable from existing social network data drawn from modern communities.

“We turned the data over lots of different ways,” said Fowler. “We looked at over a dozen measures that social network analysts use to compare networks and pretty much, the Hadza are just like us.”

“Human beings are unusual among species in the extent to which we form long-term, non-reproductive unions with other members of our species,” said Christakis. “In other words, not only do we have sex, but we also have friends.”

Previous work by Christakis and Fowler, who are coauthors of the book “Connected,” has shown that our experience of the world depends on where we find ourselves within social networks. Particular studies have found that networks influence a surprising variety of lifestyle and health factors, such as how prone you are to obesity, smoking cessation, and even happiness.

For the researchers, the Hadza offer strong new evidence that social networks are a truly ancient, perhaps integral part of the human story.

This research was funded by the National Institute on Aging and by the Science of Generosity Initiative of the University of Notre Dame.

—Written by Jake Miller

Focushms.com [en línia] Boston (EUA): focushms.com, 26 de enero de 2012 [Ref. 25 de gener de 2012] Disponible en la Internet:http://www.focushms.com/features/dawn-of-social-networks/

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