vocal grooming
n. Gossip and other forms of casual conversation that act as linguistic equivalents of the social grooming performed by some primates.
Glossies make profitable business out of our "tabloid appetite". We religiously watch news that has little relationship to truth. We bond with talk shows where people hang out their personal lives. This age-old human habit is not simply letting off steam. It is creating stories that make sense of our friends and ourselves. "Vocal grooming" is essential to our social, psychological and physical well-being.
—“Did you hear the latest?,” The Hindu, January 14, 2006
Whatever their respective evolutionary roles, it is clear that both social grooming and high social status make us feel good, and may even be good for our health. It has been shown that the mutual grooming performed by primates stimulates production of endorphins – the body's natural painkilling opiates – which makes them relaxed, and reduces their heart rate and other signs of stress. It is highly likely that the 'vocal grooming' of gossip among humans has similar effects. Experiments have also shown that raising of social status is associated with increased serotonin in the brain, which has equally beneficial physical and psychological effects. By gossiping, we may effectively be giving ourselves the natural equivalent of small doses of morphine and Prozac.
—Kate Fox, “Evolution, Alienation and Gossip,” Social Issues Research Centre, December 04, 2001
1992 (earliest)
Conventional wisdom is that language evolved to enable humans to exchange information about food sources and to allow cooperation during hunting. But it is difficult to see why humans should require this more than other primates. A more plausible suggestion is that language evolved to enable humans to integrate a larger number of individuals into their social groups.

If language is a form of "vocal grooming" designed to service a larger numbe r of relationships, then the ratio of its efficiency to that of non-human grooming should be the same as the ratio of the sizes of the two groups.

If human groups are typically about 150, and the largest non-human groups (chimpanzees and baboons) are about 55, then speech should be 150/55 times more efficient than grooming as a bonding mechanism.

The fact that grooming is limited to a one-to-one relationship means that language should make possible a one-to-three ratio. In other words, while monkeys can groom only in pairs, human conversation groups should consist of an average of four individuals (one speaker and three listeners). And indeed they do. Conversation groups in student canteens, for example, consist of an average of 3.4 individuals, with a striking tendency for groups larger than four to fragment into two or more smaller subgroups.
—Sharon Loh, “Why gossip is good for you,” The Straits Times, December 09, 1992
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