Boffins in Europe have developed a computer model that shows how opinions evolve in social networks.

And, the scientific analysis showed that the key to forming opinions lay in how well people can communicate with each other.

As a part of their experiment, researchers led by physicist Renaud Lambiotte of the University of Liege in Belgium used two groups of people.

After initially isolating the two groups from each other, they were gradually brought into contact.

The researchers found that though initially the two groups continued to form opinions independently, when communication gradually increased between them, the final opinions of the two groups were always identical.

Even a few extra links between groups were enough to "tip" their final opinions from a state of full polarization to full agreement.

"We didn't expect such an abrupt transition. It implies that even a small change in network structure can lead to drastic consequences," the New Scientist quoted Lambiotte, as saying.

The boffins now suggest the results may help to explain why polarized communities can suddenly emerge rather than gradually appear, and also why languages remain distinct across geographic borders rather than merging into a common tongue.

The researchers argue that the same dynamic may preserve differences across boundaries where communications links are weak.

The study is published in the journal Physical Review.