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Here's your wiki for the Dunbar reading.

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Dunbar's focus: "The intersection of brain, mind, and language in hominid evolution. The study looks at the size of the human brain in comparison to body size, as well as functions it is able to perform.

Primates have unusually large brains for their body size and some species within primates have disproportionately large brains for their size (humans). Dunbar ays that "primates have larger brains than other species mainly because they have larger neocortices." (See below). This means the question we ask should be "Why do primates have unusually large neocortices?"

The social brain hypothesis, which is that "the cognitive demands of living in complexly bonded social groups selected for increases in executive brain (principally neocortex)" relies essentially on a correlation between neocortex size and relevant social behavior. To that end "five separate indices of social complexity or skill have been correlated against neocortex volume in primates. These include social group size (Sawaguchi&Kudo 1990; Dunbar 1992a, 1998a; Barton 1996; Barton&Dunbar 1997), grooming clique size (Kudo & Dunbar 2001), the extent to which social skills are used in male mating strategies (Pawlowski et al. 1997), the frequency of tactical deception (Byrne 1995, 1996), and the frequency of social play (Lewis 2001)." Adding further credence is that there is a "nonsignificant relationship between all four ecological indices and relative neocortex size (at least when ecological variables are adjusted for relative body size)."

Dunbar warns that correlation does not prove causality.

According to Dunbar, "It is not a question of whether or not ecology (the environment) influences behavior, but rather is one of whether ecological/survival problems are solved explicitly by individuals acting on their own or by individuals effecting social solutions to these problems." That is to say, Dunbar is not attempting to demonstrate that the evolutionary impetus for increases in the size of neocortices is not environmental, but that the evolutionary requirements were met in homonid ancestry with increases in social group size as opposed to increases in individual fitness.

"Do social situations require different or greater cognitive powers (executive brain) than ecological problem solving?"

Dunbar states the importance of "two different levels at stake here:"

1. Whether individuals use social transmission of information to solve problems of day-to-day survival and reproduction.

2. Whether individuals are able to exploit and manipulate the mind-states of other individuals in managing the social relationships on which their day-to-day survival and reproduction depend.

OR BOTH?

Using, sharing, teaching and/or passing along "existing" or learned information/knowledge vs. Changing, improving, and/or modifying information/knowledge and then sharing, teaching, passing along, persuading or even manipulating another individual(s) to adopt new concepts of information/knowledge. Behavior modification would also apply here.

Reder & Laland "dismiss the claim that ecological innovation (including tool use and social learning) is simply a by-product of having large brains (exectuve and otherwise) for social purposes." They claim that social intelligence is a reflection of the ability to use basic executive functions in a more sophisticated way by using "reasoning," "causal analysis," and "deeper time depths for predicting future events."

This would open the door to "critical thinking" and "problem-solving" and even "visionary/insight" and "persuasive-communicative" abilities; most likely "exectuve brain" functions (frontal lobe). These traits are also found in people who possess leadership qualities/abilities.

Dunbar: "The most succinct (see below) and parsimonious (see below) causal sequence with fewest unsupported assumptions ......" "bonded social groups and the social skills that underpin this was the crucial selection pressure for the evolution of large brains, even though simple ecological pressures may have been instrumental in kicking off the process."

**Social Group Size** - Dunbar says that social group size is "constrained by relative neocortex size". According to this idea, the larger the neocortex volume the larger the social group size. (As in the number of regular grooming partners).  <span style="font-family: Arial,Helvetica,sans-serif;">﻿THE BEGINNING OF THE SOCIAL WORLD! -Core social partners (reproduction and survival become increasingly more stable through social "trust" "reliance" "bonding" and "cognitive abilities," but only through, "A sophisticated balancing act" of group cohesion. <span style="font-family: Arial,Helvetica,sans-serif;">﻿ ﻿Miniature networks = Effective social units.

<span style="font-family: Arial,Helvetica,sans-serif;">**Origins of Language** - Dunbar claims that language "must have evolved with the appearance of H. sapiens and that H. erectus almost certainly lacked a language capacity." This claim is based on the study of social grooming time versus group size and estimated grooming time requirements. Dunbar argues that "if modern humans (with their groups of about 150) bonded their social groups using grooming in the conventional primate manner, then the regression equation relating grooming time to group size in Old World monkeys and apes would predict that about 43% of day time would have to be devoted to social grooming." However, "The mean amount of time actually spent in social interaction (principally conversation) by a set of seven modern human populations (with samples from both traditional and postindustrial cultures) is exactly 20%(Dunbar 1998b)." He goes on to argue that language evolved as a supplement to the increasingly large human populations (~.5 MY) to more efficiently effect social grooming. Among the ways in which language is a more efficient means of maintaining social relationships Dunbar includes: verbal communication allows for bonds to be formed with multiple interlocutors at once, it allows grooming to occur during other activities (eating, walking, etc.), and finally that language allows us to catch up on events which took place while we were not present in the group, further increasing group cohesion.

<span style="font-family: Arial,Helvetica,sans-serif;">Dunbar: "Culture, and particularly those aspects of high culture that seem to be so crucial to the human condition, depends on advanced social cognition. This is especially clear in the context of religion and its use both in terms of facilitating a more benign world."

<span style="font-family: Arial,Helvetica,sans-serif;">The ability to think about an external supernatural world (i.e. religion) is unique to modern day humans and is based on social rather than individual development. There are four levels of intentionality when thinking about religion. “I have to //believe// that you //suppose// that there are supernatural beings who can be made to //understand// that you and I //desire// that things should happen in a particular way.” At this level we are able to abide to social norms. While most adult humans stay at level 4 intentionality society leaders add an additional intention that is, “I //believe// that I can //persuade// you to //believe// that there are supernatural beings who will //understand// what you //want//.”


 * IMPORTANT TERMS:**

__Neocortex__ - The neocortex consists of the grey matter in the brain. In primates it has deep grooves and wrinkles.This has allowed primates and especially humans to evolve new functional areas of neocortex that are responsible for enhanced cognitive skills such as working memory, speech, and language.

__ Executive Brain __ - Responsible for "goal-directed" behavior: Starting/Stopping actions, and Moniotoring/Changing and Planning future behavior. "Executive functions are high-level abilities that influence more basic abilities like attention, memory and motor skills. - Encyclopedia of Mental Disorders. []

__ Succinct __ - A verbal or written expression that is precise without wasted words. - Merriam Webster

__ Parsimonious __ - Sparing and restrained to the point of stinginess. - Merriam Webster

__ ToM (Theory of Mind) __ - A specific cognitive ability to understand others' mental states, especially their desires, goals and intentions. - Psychology Press. []