Notes on cohesion

From InterSciWiki
(Redirected from Trash)
Jump to: navigation, search

Boxes. all 20 social network studies testing effects of “cohesive blocking” (aka Structural cohesion; Harary & White'01), as implemented by Moody & White'03, cohesive blocking (aka Structural cohesion; Harary & White'01, Moody & White'03) has predictive effects such as these:

  • more positive student-attachment to the 10 schools studied,
  • attachment (vs. outmigration) to the 5 communities (and marmot homes!) studied,
  • increase in family size & wealth in the one city,
  • new tie formation among worldwide biotech firms to the more cohesive firms (and more productivity),
  • replication in 42 3rd & 4th grade American classrooms that aggressive bullying & prestige of bullies was least in classrooms with low-order cohesion (i.e., “egalitarian” networks, as found for foragers) & highest in classrooms with hierarchical cohesion (subgroups with successive higher cohesion levels).
Ahn, J.-J., C. F. Garandeau, P. C. Rodkin. 2010. Effects of Classroom Embeddedness and Density on the Social Status of Aggressive and Victimized Children. The Journal of Early Adolescence 30(1): 76-101.
  • (All findings are consistent with our hypothesis for foragers & the latter suggests a testable hypothesis for the forager-to-chiefdom contrast. Both would be major “social prosociality” findings for our study.

Test. Socially nurturing environments of expanded kinship networks present another explanation for the evolution of altruism (Kaplan, et al. 2000:183). Early humans were not a classical pair-bonding (monogamous) species but developed the cognitive ability somewhere (surely by 45,000 BP) in the Late Pleistocene for expanded kinship networks with recognition of paternal as well as maternal links and multiple extended kinship roles. With language (surely by early Holocene) came the ability to label these roles and relations linguistically, and memes for non-kin as well. Such networks would have high structural cohesion, a property of network subgroups only recently recognized in the network sciences (White and Harary 2001, Moody and White 2003, White 2012). In its egalitarian form such cohesion lends strength to resistance to dominators (White 2009) and may correlate with the sanctioning of bullies or violators of moral injunctions. Because it uniquely defines the boundaries of a continuum of increasingly intense self-scaling cohesive subgroups (diminishing in size the higher the cohesion k), structural cohesion is a well defined variable for predicting the effects of cohesion, a powerful predictive variable in kinship networks (White 2011), and corresponds to Nowak’s (2006) definition of selection by network reciprocity where b/c > k with b/c the benefit/cost ratio for each neighbor and k the average number of neighbors. Structurally cohesive groups subsets of individuals within extended kinship and affinal networks may provide another explanation for how cooperation was fostered in early foraging societies and resistance to political domination. White’s social network research groups (including Harary, Moody, McMahon, Padgett, and Oztan) are the developers of the R software (in the iGraph package) for computing structural cohesion. These measures of cohesion have been found to be predictive of prosocial and cooperative outcomes in studies of business networks, kinship and school friendship groups, and many other networks. Cohesive subgroups in kinship networks have proven to emigrate less than low cohesion community members, and to be more reproductively successful in offspring (White and Johansen 2006). A decade-long SFI collaboration between the PI (White) and political scientist J. Padgett (2010) established for a 100,000-couple kinship demography and politico-economic database developed for Renaissance Florence, 1150-1500 AD, that patrilineages more cohesively connected by marriage were those whose offspring were more reproductively successful and wealth-increasing for the group.

measures of cohesion have been found to be predictive of prosocial and cooperative outcomes in studies of

  • business networks,
  • kinship and school friendship groups

Cohesive subgroups in kinship networks have proven to emigrate less than low cohesion community members,

and to be more reproductively successful in offspring (White and Johansen 2006).
  • A decade-long SFI collaboration between the PI (White) and political scientist J. Padgett (2010) established for a 100,000-couple kinship demography and politico-economic database developed for Renaissance Florence, 1150-1500 AD, that patrilineages more cohesively connected by marriage were those whose offspring were more reproductively successful and wealth-increasing for the group.