New Delhi, Jan. 6: The hundreds of contacts stored on mobile phones or dozens of friends listed on social networking websites might not translate into abundant friendships, a study has suggested.

Each person has a unique social signature or style, which determines how much emotional and other resources will be channelled into friendships, according to research by a team of scientists in Europe.

This pattern doesn’t change even when old friendships fade and new ones blossom, say the findings, published today in the US journal Proceedings of the National Academy of Sciences.

“We have distinctive social signatures and they’re surprisingly stable over time,” Robin Dunbar, professor of experimental psychology and a member of the team at the University of Oxford in the UK, told The Telegraph.

The study is based on an analysis of 18 months of mobile phone calls to track the friends’ networks of 15 women and 15 men in a UK city as they moved from school to university or from college to work, gaining new friends and losing old ones.

“We find that people focus a very large fraction of their communication efforts on a small number of close friends or relatives,” Jari Saramaki, associate professor of biomedical engineering and computational sciences at Aalto University in Finland and the first author of the study, told this newspaper.

“This does not change even when some friends are lost and new ones gained.”

But the study also revealed how social signatures differ from person to person.

“One person may have five very close friends, four fairly close friends, six who are somewhat close, and 15 other casual acquaintances. Another person may have four very close relationships, six fairly close relationships, five somewhat close, and 20 casual acquaintances,” said team member Felix Reed-Tsochas, associate dean for research at the Said Business School at Oxford.

“In both, there are fewer strong relationships and more weak relationships, but the detailed pattern actually looks different. These patterns will persist over time even when technology influences social relationships.”

The findings reflect what scientists say are “limitations in the ability of humans to maintain many emotionally close relationships”, both because of limited time and because the emotional capital that a person can allocate between family and friends is finite.

“It’s likely that these constraints apply even when social relationships are entirely mediated through technological means, as is the case for social networking sites,” Reed-Tsochas said.

“One implication may be that there isn’t much point in trying to force people into being friends with each other on social networking sites,” Dunbar said. “They will have to drop existing friends to be able to include them.”

The researchers used two sets of data — one based on phone call records and the second on the participants’ own assessments of their emotional closeness to friends. While the study has not demonstrated that these findings also apply to social networking sites, the researchers say their results may have implications for digital networking too.

“While digital social networks allow us to be in contact with many individuals, they do not increase the numbers of close relationships,” said Saramaki. The findings raise the question of what gives rise to individual variations.