Validation of Dunbar's Number in Twitter Conversations. How Many Friends Does One Person Need?: Amazon.de: Robin Dunbar: Englische Bücher. What is the Monkeysphere? "There's that word again... " The Monkeysphere is the group of people who each of us, using our monkeyish brains, are able to conceptualize as people. If the monkey scientists are monkey right, it's physically impossible for this to be a number much larger than 150. Most of us do not have room in our Monkeysphere for our friendly neighborhood sanitation worker.
So, we don't think of him as a person. We think of him as The Thing That Makes The Trash Go Away. And even if you happen to know and like your particular garbage man, at one point or another we all have limits to our sphere of monkey concern. It's the way our brains are built. Those who exist outside that core group of a few dozen people are not people to us. Remember the first time, as a kid, you met one of your school teachers outside the classroom? I mean, they're not people. "So? Oh, not much. They're all humans and they are all equally dead. "Why should I feel bad for them? Exactly. They'd think you'd gone insane. Sort of. The Tipping Point. The Tipping Point: How Little Things Can Make a Big Difference is the debut book by Malcolm Gladwell, first published by Little Brown in 2000. The three rules[edit] Malcolm Gladwell describes the "three rules of epidemics" (or the three "agents of change") in the tipping points of epidemics.
The Law of the Few[edit] "The Law of the Few", or, as Malcolm Gladwell states, "The success of any kind of social epidemic is heavily dependent on the involvement of people with a particular and rare set of social gifts".[3] According to Malcolm Gladwell, economists call this the "80/20 Principle, which is the idea that in any situation roughly 80 percent of the 'work' will be done by 20 percent of the participants".[4] (see Pareto Principle) These people are described in the following ways: Connectors are the people in a community who know large numbers of people and who are in the habit of making introductions.
Salesmen are "persuaders", charismatic people with powerful negotiation skills.
Christopher Allen. THE OPTIMAL SIZE OF A TERRORIST NETWORK. Distributed, dynamic terrorist networks cannot scale like hierarchical networks. The same network design that makes them resiliant against attack puts absolute limits on their size. If so, what are those limits? A good starting point is to look at limits to group size within peaceful online communities on which we have extensive data -- terrorist networks are essentially geographically dispersed online communities.
Chris Allen does a good job analyzing optimal group size with his critique of the Dunbar number. His analysis (replete with examples) shows that there is a gradual fall-off in effectiveness at 80 members, with an absolute fall-off at 150 members. Al Qaeda may have been able to grow much larger than this when it ran physical training camps in Afghanistan. This leads us to optimal group size, which according to Chris Allen's online group analysis, can be seen at two levels: both small and medium sized. This size dynamic can also be seen in criminal organizations. Dunbar. Security, Group Size, and the Human Brain. If the size of your company grows past 150 people, it's time to get name badges. It's not that larger groups are somehow less secure, it's just that 150 is the cognitive limit to the number of people a human brain can maintain a coherent social relationship with. Primatologist Robin Dunbar derived this number by comparing neocortex -- the "thinking" part of the mammalian brain -- volume with the size of primate social groups.
By analyzing data from 38 primate genera and extrapolating to the human neocortex size, he predicted a human "mean group size" of roughly 150. This number appears regularly in human society; it's the estimated size of a Neolithic farming village, the size at which Hittite settlements split, and the basic unit in professional armies from Roman times to the present day. Larger group sizes aren't as stable because their members don't know each other well enough. Instead of thinking of the members as people, we think of them as groups of people. Rule of 7: The Ideal Work Group Size | BNET. Last Updated Sep 28, 2010 12:18 PM EDT In the movie The Magnificent Seven, a group of crusty gunfighters led by Yul Brynner successfully protects a small Mexican village from desperadoes. The movie itself is a remake of Akira Kurosawa's Seven Samurai. As it turns out, seven is a great number for not only forming an effective fictional fighting force, but also for task groups that use spreadsheets instead of swords to do their work.
That's according to the new book Decide & Deliver: 5 Steps to Breakthrough Performance in Your Organization (Harvard Business Press). Once you've got 7 people in a group, each additional member reduces decision effectiveness by 10%, say the authors, Marcia W. Unsurprisingly, a group of 17 or more rarely makes a decision other than when to take a lunch break. Larger groups only seem to work when they adopt a strict set of governing policies, such as spelling out when a majority is needed to ratify a decision versus a plurality. . © 2010 CBS Interactive Inc.. Nexus: Small Worlds and the Groundbreaking Science of Networks (9780393041538): Mark Buchanan.
Research Intelligence - Issue No 17 - The ultimate brain teaser. Relative to their body size, monkeys, apes and humans have unusually big brains. It has been suggested that this reflects the complexity of their social lives. This hypothesis is gaining support thanks to ground-breaking research by a University of Liverpool scientist, whose methods have been taken up by primate researchers around the world. These same methods could soon shed light on the story of human evolution. Judged by our genomes, there's surprisingly little difference between humans and chimps: 95% of our DNA is similar, making chimps our closest ape 'cousins'.
Clearly, brain size plays a crucial role: all primates have big brains relative to their body size, but human brains are disproportionately large. Why did these changes take place in primates in general, and humans so particularly? Over the past decade, a Liverpool University scientist has subjected this ‘social brain’ hypothesis to rigorous tests. Innovative Models Significant correlations The human dimension back to top. The ‘Path’ to Social Network Serenity Is Lined With 50 Friends | Epicenter Three ideas lurk behind Path, a new social service that launches Monday as an iPhone app. As CEO Dave Morin explains it, the first two are the products of scientific research. As a former Facebook exec — Morin was responsible for the Facebook platform that supported apps from outside developers — he was drawn to the work of evolutionary anthropologist R.I.M. Dunbar, whose work on the primate neocortex suggested that brain size limits the number of close connections.
This applies to grooming cliques among apes and Internet social networks among humans. Dunbar has recently been scientifically frolicking in the anthropological gold mine of Facebook and has revealed his early findings that digitally, as well as in the real world, our species is incapable of managing an “inner circle” of more than 150 friends. That increment became known as “Dunbar’s Number.” Is a ‘Favored Fifty’ the magic number for your Personal Network? This leads to the third idea behind Path. Communities of practice and Dunbar's number. Posted at 17:01 in . Dunbar is an anthropologist at the University College of London who hypothesized that there is a cognitive limit to the number of individuals with whom any one person can maintain stable relationships, and predicted that 150 is the "mean group size" for humans.
Ross Mayfield wrote a very interesting post last year starting from there on Ecosystem of Networks and came out with this nice summarized graph, which I have been struggling a little with to be honest since I saw it for the first time (are axes consistent from one raph to the other?..) But still it is intriguing. Christopher Allen just elaborated further on this in a remarkable post on The Dunbar Number as a Limit to Group Sizes In my experience and vision of communities of practice, I tend to find similar numbers floating around.
At the center, the "core group" of the community of practice is typically composed of 5 to 7 people. Continue reading 'Communities and Dubar's Number'... Thanks for signing in, . Robin Dunbar: How Many Friends Does One Person Need? Bio Robin Dunbar Robin Ian MacDonald Dunbar is a British anthropologist and evolutionary biologist, specializing in primate behavior. He is best known for formulating Dunbar's number, roughly 150, a measurement of the "cognitive limit to the number of individuals with whom any one person can maintain stable relationships". Professor Dunbar is a director of the British Academy Centenary Research Project (BACRP) "From Lucy to Language: The Archaeology of the Social Brain" and is involved in the planned BACRP "Identifying the Universal Religious Repertoire".
To download this program become a Front Row member. ZOOM IN: Learn more with related books and additional materials. Encyclopædia Britannica Article anthropology The “science of humanity.” Anthropology on britannica.com © 2010 Encyclopædia Britannica, Inc. If you’re working in a big group, you’re fighting human nature. When you’ve got a small group, you don’t need to constantly formalize things. You communicate and you know what’s going on. If you have a question about something, you ask someone. Formalized rules, deadlines, and documents start to seem silly.
Everyone’s already on the same page anyway. Ten-groups According to British author Antony Jay, there are centuries of evidence to support the idea that small groups are the most efficient. He offers up interesting examples to back up the theory, from sports teams to juries to army squads: Jay draws attention to units of around this size in many fields beyond the corporation.
Groups this size succeed because they have mutual dependence and a common objective: This group displays qualities in addition to its size. Two-pizza teams The tech world equivalent of ten-groups: two-pizza teams. Bottom line If you’re working in a group bigger than 15 people, you’re fighting human nature. Related Some other Antony Jay quotes: Dunbar's numbers for ideal group size. | Leading Leaders - Identity Based Leadership. From a single person to group sizes of over 1000 people, the ideal number of people in any group is becoming quite a science. After some research I have discovered that not only are there some serious thinkers spending quite a bit of time developing this idea, but these thought processes about group sizes have been around in the military for 100’s of years. One thing is certain, adjusting the number of people in a group size, directly impacts the group’s cohesion and performance. How many people are in your groups? Anthropologist Robin Dunbar found that the MAXIMUM number of people that a person could keep up with socially at any given time, called gossip maintenance, was 150.
This doesn’t mean that people don’t have 150 people in their social network, but that they can only keep tabs on 150 people at any given point. Dunbar’s Numbers What is the ideal number? Perhaps it is at 5 that the feeling of “team” really begins. Military groups sizes Two questions then: Dunbar's number.