Human Social Networks

(Notes by Van Sloan, author of this Social Quotient website.)

New research shown on PBS TV indicates that the large size of human brains may be due to the large numbers of individuals that one knows well (about 150). Chimpanzees know well about 55 other chimps, and their brain size is proportionately smaller. The same PBS program also showed how babies from 3 to 10 months old preferred helping over hindering characters, indicating that such preference is largely inborn. The articles below detail these findings.

This research gives clues why social skills are a most important characteristic of successful human activity. Unlike IQ's, which change little over one's lifetime, social skills can be improved – a major theme of this website.

January 17th, 2010 on PBS

Video Excerpt: Social Networks and the Spark

At Oxford University, Alan Alda finds out from Robin Dunbar how human social networks compare to those of chimps, and at Yale University, watches babies as young as three months old pick cooperative puppets over those that won’t play.


Alan AldaWhat is the nature of human uniqueness?

In a three-part series originally broadcast on PBS in January 2010, Alan Alda takes this question personally, visiting with dozens of scientists on three continents -- even undergoing an examination of his own brain.

NEW SCIENTIST   21.11.92
ROBIN DUNBAR- professor of biological anthropology at University College London.


(excerpts from )

Humans live in much larger groups than other primates. Language may have evolved as a form of grooming to allow us to live with so many people.

Why do primates have such big brains?
There are two general kinds of theories. The more conventional one is that they need big brains to help them to find their way about the world and solve problems in their daily search for food. 
The alternative type of theory is that the complex social world in which primates live has provided the impetus for the evolution of large brains. The main version of the social intelligence theory, sometimes known as the Machiavellian intelligence hypothesis, has the merit of identifying the thing that sets primates apart from all other animals—the complexity of their social relationships. 

Primate societies seem to differ from those of other animals in two key respects. The first is the dependence on intense social bonds between individuals, which gives primate groups a highly structured appearance. Primates cannot join and leave these groups as easily as animals in the relatively amorphous herds of migrating antelope or the swarms of many insects. Other species may have groups that are highly structured in this way—elephants and prairie dogs are two obvious examples—but these animals differ from primates in a second respect. This is that the primates use their knowledge about the social world in which they live to form more complex alliances with each other than do other animals. 

Language has two interesting properties compared to grooming: you can talk to several people at once and you can talk while travelling, eating or working in the fields. Conventional wisdom has always supposed that language evolved to enable humans to exchange information about food sources and to aid cooperation during hunting. But it is difficult to see why humans should be any more in need of this than other primates or, if hunting is the issue, the social carnivores such as lions and wolves. A more plausible suggestion is that language evolved to enable humans to integrate a larger number of individuals into their social groups. 

Importance of a good gossip

There is, of course, another way in which language allows us to integrate a large number of social relationships, and that is by allowing us to exchange information about other individuals who are not present. In other words, by talking to one person, we can find out a great deal about how other individuals are likely to behave, how we should react to them when we actually meet them and what kinds of relationships they have with third parties. All these things allow us to coordinate our social relationships within a group more effectively. And this is likely to be especially important in the dispersed groups that are characteristic of humans. 
This could explain our fascination for social gossip in the newspapers, and why gossip about relationships accounts for an overwhelming proportion of human conversations. Even conversation in such august places as university coffee rooms tend to wing back and forth between academic issues and gossip about individuals. To get some idea of ow important gossip is, we monitored conversations in a university refectory, scoring the topic at 30-second intervals. Social relationships and personal experiences accounted for about 70 per cent of conversation time. About half of this was devoted to he relationships or experiences of third parties (people not present). Males, however, tended to talk more about their own relationships and experiences whereas females tended to talk most about other people’s. 

What we seem to have here, then, is a new theory for the evolution of language that also seems to account for a number of other facets of human behaviour. The theory explains why gossip about other people is so fascinating; it explains why human societies are so often hierarchies; it predicts the small size of conversation groups; it meshes well with our general understanding of why primates have larger brains than other mammals, and it agrees with the general view that language only evolved with the appearance of Homo sapiens. 

Babies can spot nice and nasty characters

Infants as young as six months instinctively prefer helpful characters.

Michael Hopkin

(from )

Infants have more social savvy than usually given credit for.

You might scoff at doting parents who proudly tell you that their youngster, even though still in diapers, takes an instant liking to kind-hearted people and shows disdain for less savoury characters. But a new experiment shows that such claims could be more than parental pride. Babies, it seems, have a lot more social savvy than we credit them with.

Research led by Kiley Hamlin, a graduate student at Yale University in New Haven, Connecticut, shows that babies less than a year old can judge the niceness or nastiness of others, even when watching events that don't directly affect them. The researchers made the discovery using nothing more high-tech than a simple puppet show.

After watching the show, the babies, aged either six months or ten months, instinctively preferred 'nice' characters over less helpful ones. This kind of skill may be useful in helping them learn the right values as their social awareness develops later in childhood.

"We knew that babies were socially skilled, but we weren't aware that they were so skilled that they could track people by their behavioural tendencies; how they might treat someone else," says Hamlin.

Evil puppets

Going up? Kids tend to approach the puppet that helped its mate up the hill. Nature

Hamlin and her colleagues showed the babies a puppet show in which the central character, a brightly coloured round wooden block complete with googly eyes, tried in vain to scale a steep hill. The puppet was then either given a friendly shove up the hill by a 'good Samaritan' puppet, or thwarted by an evil puppet who pushed the climber back down.

After the show, the babies were encouraged to reach out for either the helper or the hinderer puppet. Almost all favoured the helper, Hamlin and her colleagues report in this week's Nature1.

"This suggests to us that at least they're able to tell them apart, and also that they have some tendency towards the positive helper," Hamlin says. "We were shocked by the strength of the responses. We thought infants would be sensitive to the behaviour of others, but didn't anticipate the extent of this."

What's more, the effect was not so marked when the puppets' googly eyes were removed, showing that the babies identify with the puppets as characters and make their choice on the basis of the characters' actions, even though the babies were not personally affected by the show's events.

In a second experiment, the babies were again shown the puppet show, and then saw the climber subsequently appear to 'make friends' with either helper or hinderer. The older babies spent longer looking at it when the climber approached the hinderer, suggesting that they found this event more surprising. The result shows that the older babies, although not the younger ones, can draw fairly sophisticated conclusions about the social attitudes and motives of others, say the researchers.

Parental pride

"You get a lot of parents saying their babies have these reactions to different kinds of people," says Hamlin. "It's been said anecdotally but never tested experimentally before."

The fact that babies can make choices like this at such an early age suggests that the ability to choose between nice and nasty may even be innate, Hamlin says. This may even form the bedrock of a child's social development, she suggests — by favouring helpful over unhelpful people, a growing child may sow the seeds for strong social ties with others in later life.

"Just by spending more time with positive people, they might get a different set of learning inputs than if they spent time with negative people, and over time you can see that could have a real influence on their development," Hamlin says. 

Published online 21 November 2007 | Nature | doi:10.1038/news.2007.278