Social Networks From the Ground Up -- CSSSA 2011 Presentation

8/3/2019 Social Networks From the Ground Up -- CSSSA 2011 Presentation

1/38

Social Networks

From the Ground Up

Maksim Tsvetovat, Bill Kennedy, Omar Guerrero

George Mason University


2/38


3/38

Friend of a friend is myfriend

Enemy of a friend is myenemy


4/38


5/38

Homophily /

Diffusion Similarity drives likelyhood of tie and/or

tie strength

Tie strength drives information diffusionacross tie

Birds of a feather flock together Tell me who your friends are...


6/38

Structural Holes

Span longer distances in terms ofhomophily

Access to differential information Control benefits / brokerage Help form small-world networks


7/38

Simmelian Ties /

Triads

Formation of distinct cultural artifacts(jargon, shared understanding) Feedback loops cement the tie strength

and homophily


8/38

WHY?


9/38

What is theunderlying

mechanism fromwhich network

structures evolve?


10/38

Hypothesis:Social behaviors can emerge

from neuro-cognitivemechanisms of the human

brain


11/38

or...

Human brain has aSocial Operating

System


12/38

Hypothesis 2:

Social Networkformation is mediatedby neurotransmitters

Dopamine andOxytocin (and maybe

others)


13/38

Evidence James Fowler -- Social networks make you fat Liberal/conservative attitudes may be genetically

modulated

Gerics, Schultz

Introversion vs. Extroversion modulated by dopamine(D1 receptors); also affects homophily

Creativity modulated by dopamine (D2 receptors)

Cho, DeVries, et al

Marital fidelity related to oxytocin and vasopressinreceptors

Dunbar -- network size related to size of PreFrontalCortex (PFC); Bickart -- network size related to size of


14/38

... in short

Mounting evidence on many levelssupports the hypothesis that socialbehavior is neurotransmitter-mediated

Therefore, social network structuresmay emerge from genetic factors


15/38

Units of Analysis

Neuroscience Psychology Social Sciences


16/38

Can we model S-OS?

Massive agent-based model

We build agents with an artificial brainencompassing dopamine and oxytocincircuits

Agents interact with others and theenvironment; there are external stimuliin the environment


17/38


18/38

Stimuli

External -- from the environment

Communicated -- from anotherindividual Internal -- a private, interal context of

remembered experiences andnarratives


19/38

Stimuli affect DA levels & wellness state Wellness = higher abstraction to deal

with perception & physiologicalreactions

Agents well-being is visible to itsneighbors via mirror neurons

Primitive movements (food seeking)


20/38


21/38

Herding Emerges

from simple signaling


22/38


23/38

Associative Learning Salient stimuli are associated with eachother if they occur within a single

dopamine spike


24/38

!!!

Agents associate abstract signals withother individuals

Associations become socially shared


25/38

Agents gave eachother names!


26/38


27/38

Predators

Predators cause pain but do not kill Observing an attack causes empathy

pain via mirror neurons


28/38

Emergence of

Sociality Simple sociality --

Associate behavior of others with aconcrete stimulus-response pair

If you see a lion, run If you see others running, run!


29/38

Shared concept ofpredator emerges


30/38


31/38

Narratives A traversal through the semantic

graph is a grammar


32/38

ChomskysUniversal Grammar


33/38

More complex

semantics

Dominance/submission signals Hierarchy -- alpha, beta, gammas (the

rest)


34/38


35/38

... as PFC develops...

Ability for reasoning (i.e. discriminatingpaths through the semantic network)increases

Ability to keep more informationincreases


36/38

Higher Sociality Families Clans, tribes

Emergent, evolving social norms Emergence of language and abstraction

Emergence of cultural diversity Emergence of macro-scale socialcomplexity


37/38

.........


38/38

Social Networks From the Ground Up -- CSSSA 2011 Presentation

Documents

Transcript of Social Networks From the Ground Up -- CSSSA 2011 Presentation