Dunbar’s Number
   HOME





Dunbar’s Number
Dunbar's number is a suggested cognitive limit to the number of people with whom one can maintain stable social relationships—relationships in which an individual knows who each person is and how each person relates to every other person. This number was first proposed in the 1990s by Robin Dunbar, a British anthropologist who found a correlation between primate brain size and average social group size. By using the average human brain size and extrapolating from the results of primates, he proposed that humans can comfortably maintain 150 stable relationships. There is some evidence that brain structure predicts the number of friends one has, though causality remains to be seen. Dunbar explained the principle informally as "the number of people you would not feel embarrassed about joining uninvited for a drink if you happened to bump into them in a bar." Dunbar theorised that "this limit is a direct function of relative neocortex size, and that this, in turn, limits group size ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Robin Dunbar
Robin Ian MacDonald Dunbar (born 28 June 1947) is a British biological anthropologist, evolutionary psychologist, and specialist in primate behaviour. Dunbar is professor emeritus of evolutionary psychology of the Social and Evolutionary Neuroscience Research Group in the Department of Experimental Psychology at the University of Oxford. He is best known for formulating Dunbar's number, a measurement of the "cognitive limit to the number of individuals with whom any one person can maintain stable relationships". Education The son of an engineer, Dunbar was privately educated at Magdalen College School, Brackley. He went on to study at the University of Oxford as an undergraduate student at Magdalen College, Oxford, where his teachers included Niko Tinbergen; he completed his Bachelor of Arts in Psychology and Philosophy in 1969. Dunbar then went on to the Department of Psychology of the University of Bristol and completed his PhD in 1974 on the social organisation of the ge ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Evolutionary Psychology
Evolutionary psychology is a theoretical approach in psychology that examines cognition and behavior from a modern evolutionary perspective. It seeks to identify human psychological adaptations with regard to the ancestral problems they evolved to solve. In this framework, psychological traits and mechanisms are either functional products of natural selection, natural and sexual selection in human evolution, sexual selection or non-adaptive Spandrel (biology), by-products of other adaptive traits. Adaptationist thinking about Physiology, physiological mechanisms, such as the heart, Lung, lungs, and the liver, is common in evolutionary biology. Evolutionary psychologists apply the same thinking in psychology, arguing that just as the heart evolved to pump blood, the liver evolved to detoxify poisons, and the kidneys evolved to filter turbid fluids there is modularity of mind in that different psychological mechanisms evolved to solve different adaptive problems. These evolutionary ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Great Ape
The Hominidae (), whose members are known as the great apes or hominids (), are a taxonomic family of primates that includes eight extant species in four genera: '' Pongo'' (the Bornean, Sumatran and Tapanuli orangutan); '' Gorilla'' (the eastern and western gorilla); '' Pan'' (the chimpanzee and the bonobo); and ''Homo'', of which only modern humans (''Homo sapiens'') remain. Numerous revisions in classifying the great apes have caused the use of the term ''hominid'' to change over time. The original meaning of "hominid" referred only to humans (''Homo'') and their closest extinct relatives. However, by the 1990s humans and other apes were considered to be "hominids". The earlier restrictive meaning has now been largely assumed by the term ''hominin'', which comprises all members of the human clade after the split from the chimpanzees (''Pan''). The current meaning of "hominid" includes all the great apes including humans. Usage still varies, however, and some scientis ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Orangutan
Orangutans are great apes native to the rainforests of Indonesia and Malaysia. They are now found only in parts of Borneo and Sumatra, but during the Pleistocene they ranged throughout Southeast Asia and South China. Classified in the genus ''Pongo'', orangutans were originally considered to be one species. In 1996, they were divided into two species: the Bornean orangutan (''P. pygmaeus'', with three subspecies) and the Sumatran orangutan (''P. abelii''); a third species, the Tapanuli orangutan (''P. tapanuliensis''), was identified definitively in 2017. The orangutans are the only surviving members of the subfamily Ponginae, which diverged genetically from the other hominids (gorillas, chimpanzees, and humans) between 19.3 and 15.7 million years ago. The most arboreal of the great apes, orangutans spend most of their time in trees. They have proportionally long arms and short legs, and have reddish-brown hair covering their bodies. Adult males weigh about , while female ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Gibbon
Gibbons () are apes in the family Hylobatidae (). The family historically contained one genus, but now is split into four extant genera and 20 species. Gibbons live in subtropical and tropical forests from eastern Bangladesh and Northeast India to Southeast Asia and Indonesia (including the islands of Sumatra, Borneo and Java). Also called the lesser apes, gibbons differ from the great apes ( chimpanzees, gorillas, orangutans and humans) in being smaller, exhibiting low sexual dimorphism, and not making nests. Like all of the apes, gibbons are tailless. Unlike most of the great apes, gibbons frequently form long-term pair bonds. Their primary mode of locomotion, brachiation, involves swinging from branch to branch for distances up to , at speeds as fast as . They can also make leaps up to , and walk bipedally with their arms raised for balance. They are the fastest of all tree-dwelling, nonflying mammals. Depending on the species and sex, gibbons' fur coloration varies from ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Anthropoid Ape
The Hominidae (), whose members are known as the great apes or hominids (), are a taxonomic family of primates that includes eight extant species in four genera: '' Pongo'' (the Bornean, Sumatran and Tapanuli orangutan); ''Gorilla'' (the eastern and western gorilla); '' Pan'' (the chimpanzee and the bonobo); and ''Homo'', of which only modern humans (''Homo sapiens'') remain. Numerous revisions in classifying the great apes have caused the use of the term ''hominid'' to change over time. The original meaning of "hominid" referred only to humans (''Homo'') and their closest extinct relatives. However, by the 1990s humans and other apes were considered to be "hominids". The earlier restrictive meaning has now been largely assumed by the term ''hominin'', which comprises all members of the human clade after the split from the chimpanzees (''Pan''). The current meaning of "hominid" includes all the great apes including humans. Usage still varies, however, and some scientists ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Bayesian Inference
Bayesian inference ( or ) is a method of statistical inference in which Bayes' theorem is used to calculate a probability of a hypothesis, given prior evidence, and update it as more information becomes available. Fundamentally, Bayesian inference uses a prior distribution to estimate posterior probabilities. Bayesian inference is an important technique in statistics, and especially in mathematical statistics. Bayesian updating is particularly important in the dynamic analysis of a sequence of data. Bayesian inference has found application in a wide range of activities, including science, engineering, philosophy, medicine, sport, and law. In the philosophy of decision theory, Bayesian inference is closely related to subjective probability, often called "Bayesian probability". Introduction to Bayes' rule Formal explanation Bayesian inference derives the posterior probability as a consequence of two antecedents: a prior probability and a "likelihood function" derive ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Peter Killworth
Professor Peter D. Killworth (27 March 1946 – 28 January 2008) was an English scientist known for his work on oceanography and on the study of social networks. A prolific writer, he published more than 160 scientific papers over the course of his career.
He was also known for his work as a pioneering author of text interactive fiction games during the early 1980s. Peter Killworth died in 2008 from motor neurone disease.


Oceanography

The major part of Peter Killworth's career was spent as an oceano ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Cybercrime
Cybercrime encompasses a wide range of criminal activities that are carried out using digital devices and/or Computer network, networks. It has been variously defined as "a crime committed on a computer network, especially the Internet"; Cybercriminals may exploit vulnerabilities in computer systems and networks to gain unauthorized access, steal sensitive information, disrupt services, and cause financial or reputational harm to individuals, organizations, and governments. In 2000, the tenth United Nations Congress on the Prevention of Crime and the Treatment of Offenders classified cyber crimes into five categories: unauthorized access, damage to computer data or programs, sabotage to hinder the functioning of a computer system or network, unauthorized interception of data within a system or network, and computer espionage. Internationally, both state and non-state actors engage in cybercrimes, including espionage, financial theft, and other cross-border crimes. Cybercrimes c ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Terrorist Network Analysis
Network science is an academic field which studies complex networks such as telecommunication networks, computer networks, biological networks, cognitive and semantic networks, and social networks, considering distinct elements or actors represented by ''nodes'' (or ''vertices'') and the connections between the elements or actors as ''links'' (or ''edges''). The field draws on theories and methods including graph theory from mathematics, statistical mechanics from physics, data mining and information visualization from computer science, inferential modeling from statistics, and social structure from sociology. The United States National Research Council defines network science as "the study of network representations of physical, biological, and social phenomena leading to predictive models of these phenomena." Background and history The study of networks has emerged in diverse disciplines as a means of analyzing complex relational data. The earliest known paper in this f ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Complexity Theory And Organizations
Complexity theory and organizations, also called complexity strategy or complex adaptive organizations, is the use of the study of complexity systems in the field of strategic management and organizational studies. It draws from research in the natural sciences that examines uncertainty and non-linearity. Complexity theory emphasizes interactions and the accompanying feedback loops that constantly change systems. While it proposes that systems are unpredictable, they are also constrained by order-generating rules. Complexity theory has been used in the fields of strategic management and organizational studies. Application areas include understanding how organizations or firms adapt to their environments and how they cope with conditions of uncertainty. Organizations have complex structures in that they are dynamic networks of interactions, and their relationships are not aggregations of the individual static entities. They are adaptive; in that, the individual and collecti ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Flight Centre
Flight Centre Travel Group (FCTG) is an Australian travel agency. It was founded in 1982, and is headquartered in Brisbane, Australia. FCTG operates under multiple names in Australia, New Zealand, United States, Canada, United Kingdom, South Africa, India, China mainland, Hong Kong (China), Singapore, United Arab Emirates, and Mexico, and licenses its name in a further 80 countries. In the United States, the company operates under the Liberty Travel and Travel Associates retail brands and GOGO Worldwide Vacations as a wholesale brand. It also operates StudentUniverse, FCM Travel Solutions, Corporate Traveler, ciEvents, Campus Travel, Stage & Screen, and Healthwise. History The company was co-founded by Graham Turner and Geoff Harris in 1982 and began with a store in Sydney. Flight Centre South Africa opened its first retail store in Eastgate, Bedfordview, Johannesburg on 17 Dec 1994. In 1995, Flight Centre UK and Flight Centre Canada opened.André Sammartino (2007), 'Retai ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]