número de Dunbar
· Outline Dunbar's number is a suggested cognitive limit to the number of people with whom one can maintain stable social relationships. These are relationships in which an individual knows who each person is and how each person relates to every other person. This number was proposed by Dunbar, 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 only comfortably maintain 150 stable relationships . Proponents assert that numbers larger than this generally require more restrictive rules, laws, and enforced norms to maintain a stable, cohesive group. It has been proposed to lie between 100 y 230, with a commonly used value of 150. Dunbar's number states the number of people one knows and keeps social contact with, and it does not include the number of people known personally with a ceased social relationship, nor people just generally known with a lack of persistent social relationship, a number which might be much higher and likely depends on long-term memory size. Dunbar's number was first proposed by British anthropologist Robin Dunbar, who theorized that "this limit is a direct function of relative neocortex size, and that this in turn limits group size ... the limit imposed by neocortical processing capacity is simply on the number of individuals with whom a stable inter-personal relationship can be maintained." On the periphery, the number also includes past colleagues, such as high school friends, with whom a person would want to reacquaint themself if they met again. Contenido 1 Research background 2 Alternative numbers 3 Ver también 4 Referencias 5 External links Research background Primatologists have noted that, due to their highly social nature, non-human primates have to maintain personal contact with the other members of their social group, usually through grooming. Such social groups function as protective cliques within the physical groups in which the primates live. The number of social group members a primate can track appears to be limited by the volume of the neocortex region of their brain. This suggests that there is a species-specific index of the social group size, computable from the species' mean neocortex volume. En un 1992 artículo, Dunbar used the correlation observed for non-human primates to predict a social group size for humans. Using a regression equation on data for 38 primate genera, Dunbar predicted a human "mean group size" de 147.8 (casually represented as 150), a result he considered exploratory due to the large error measure (un 95% confidence interval of 100 Para 230). Dunbar then compared this prediction with observable group sizes for humans. Beginning with the assumption that the current mean size of the human neocortex had developed about 250,000 years BCE, es decir. during the Pleistocene, Dunbar searched the anthropological and ethnographical literature for census-like group size information for various hunter-gatherer societies, the closest existing approximations to how anthropology reconstructs the Pleistocene societies. Dunbar noted that the groups fell into three categories — small, medium and large, equivalent to bands, cultural lineage groups and tribes — with respective size ranges of 30-50, 100-200 y 500-2500 members each. Dunbar's surveys of village and tribe sizes also appeared to approximate this predicted value, Incluido 150 as the estimated size of a neolithic farming village; 150 as the splitting point of Hutterite settlements; 200 as the upper bound on the number of academics in a discipline's sub-specialization; 150 as the basic unit size of professional armies in Roman antiquity and in modern times since the 16th century; and notions of appropriate company size. Dunbar has theorized that 150 would be the mean group size only for communities with a very high incentive to remain together. For a group of this size to remain cohesive, Dunbar speculated that as much as 42% of the group's time would have to be devoted to social grooming. Correspondingly, only groups under intense survival pressure, such as subsistence villages, nomadic tribes, and historical military groupings have, de media, achieved the 150-member mark. Además, Dunbar noted that such groups are almost always physically close: "... we might expect the upper limit on group size to depend on the degree of social dispersal. In dispersed societies, individuals will meet less often and will thus be less familiar with each, so group sizes should be smaller in consequence." Así, the 150-member group would only occur because of absolute necessity, es decir. due to intense environmental and economic pressures. Dunbar proposes furthermore that language may have arisen as a "cheap" means of social grooming, allowing early humans to efficiently maintain social cohesion. Without language, Dunbar speculates, humans would have to expend nearly half their time on social grooming, which would have made productive, cooperative effort nearly impossible. Language may have allowed societies to remain cohesive, while reducing the need for physical and social intimacy. Dunbar's number has since become a major meme of interest in anthropology, sociología, Estadísticas, and business management. As with many theoretical values, it has occasionally been abused and mistaken as a "magic number". Alternative numbers Anthropologist H. Russell Bernard and Peter Killworth and associates have done a variety of field studies in the United States that came up with an estimated mean number of ties, 290, which is roughly double Dunbar's estimate. The Bernard–Killworth median of 231 is lower, due to[cita necesaria] upward straggle in the distribution, but still appreciably larger than Dunbar's estimate. The Bernard–Killworth estimate of the maximum likelihood of the size of a person's social network is based on a number of field studies using different methods in various populations. It is not an average of study averages but a repeated finding. No obstante, the Bernard–Killworth number has not been popularized as widely as Dunbar's. See also Allen curve Bowling Alone Continuum concept References ↑ Cite error: No válido etiqueta; no text was provided for refs named dunbar92 ↑ PMID 23515066 (PMID 23515066) La cita se completará automáticamente en unos minutos.. Jump the queue or expand by hand ↑ PMID 22506743 (PMID 22506743) La cita se completará automáticamente en unos minutos.. Jump the queue or expand by hand ↑ PMID 22216422 (PMID 22216422) La cita se completará automáticamente en unos minutos.. Jump the queue or expand by hand ↑ PMID 21826200 (PMID 21826200) La cita se completará automáticamente en unos minutos.. Jump the queue or expand by hand ↑ Gladwell, Malcolm (2000). The Tipping Point – How Little Things Make a Big Difference, 177–181, 185–186, Poco, marrón y compañía. ↑ Purves, D. (2008). Principles of cognitive neuroscience. Sinauer Associates Inc. ↑ . "Unravelling the size distribution of social groups with information theory on complex networks". ↑ includeonly>"Don't Believe Facebook; You Only Have 150 Friends", NPR, 4 Junio 2011. ↑ includeonly>Carl Bialik. "Sorry, You May Have Gone Over Your Limit Of Network Friends", The Wall Street Journal Online, 16 Noviembre 2007. Recuperado el 2007-12-02. ↑ McCarty, C. (2000). Comparing Two Methods for Estimating Network Size. Human Organization 60 (1): 28–39. ↑ DOI:10.1016/0378-8733(87)90017-7 This citation will be automatically completed in the next few minutes. You can jump the queue or expand by hand ↑ H. Russell Bernard. "Honoring Peter Killworth's contribution to social network theory." Paper presented to the University of Southampton, 28 Septiembre 2006. HTTP://nersp.osg.ufl.edu/~ufruss/ Sawaguchi, T., & Kudo, H. (1990), Neocortical development and social structure in primates, primates 31: 283-290. Dunbar, R.I.M. (1992) Neocortex size as a constraint on group size in primates, Journal of Human Evolution 22: 469-493. Dunbar, R.I.M. (1993), Coevolución del tamaño neocortical, tamaño del grupo y lenguaje en humanos, Ciencias del Comportamiento y del Cerebro 16 (4): 681-735. External links A pre-publication version of Coevolution of neocortical size, tamaño del grupo y lenguaje en humanos. (See also Bibliography section there.) University of Liverpool Research Intelligence No. 17, Agosto 2003 - "The ultimate brain teaser" - an article on Dunbar's research. Detailed article about Dunbar's number and its application to online gaming Mospos blog entry - Communities of practice and Dunbar's number This page uses Creative Commons Licensed content from Wikipedia (ver autores).
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