Because our evolutionary ancestors were not as adept at getting food in the forests as other animals around at the time, they were forced to move out into the savannahs to find food. Many explanations have been offered for this, including the fact that our ancestors were not able to digest unripe fruit, while their competitors for food did have this ability. This move to the savannah led to greater predation, since they were out in the open and in better view of predators than they would have been in the forests.
To protect from predation, group sizes had to increase, so that more individuals could fight off or scare away the predators. But with greater group sizes there is a greater need to form alliances. At this point in our evolutionary history, though, grooming, which is both labor-intensive and time-consuming, was the primary means through which alliances among individuals were formed.
In setting out the gossip hypothesis, Robin Dunbar theorizes that once the group size increases to approximately 150, grooming is no longer a viable method of alliance-building because it would require that individuals engage in this activity approximately thirty percent of their waking life, a percentage of time not spent grooming by any presently surviving primates. So, spoken natural language, which could be done with multiple individuals, and was less time-consuming, emerged and replaced grooming as a more efficient means of “social networking.”
It may seem strange that human language evolved not to convey information like “There’s a lion over there,” but to form social bonds for mutual support. But conveying information and forming social alliances are not mutually exclusive: Think of how much present communication, involves completely useless or uninteresting information! Consider “Hi, how are you?,” “Nice day out,” and “Goodbye” as examples. In these cases, as in countless others, not much in the way of valuable information is conveyed by these utterances. However, in terms of forming social alliances, they are often useful, and indeed expected. Also, information may be shared not simply for the usefulness of the information, but to bond the sharer of the information with receiver.
Source of Information : Open Court-Facebook and Philosophy 2010