Robin Dunbar "Has the Internet Changed Our Social World?"

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Has the Internet Changed Has the Internet Changed Our Social World? Our Social World? Robin Dunbar

description

Presentation to 26th HBES Workshop Natal, 30 July 2014 - Internet Science official JRA6 workshop.

Transcript of Robin Dunbar "Has the Internet Changed Our Social World?"

Page 1: Robin Dunbar "Has the Internet Changed Our Social World?"

Has the Internet Changed Has the Internet Changed Our Social World?Our Social World?

Robin Dunbar

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The Global Village?

The Internet was based on the promise of enlarging your social world beyond the

limits of the local village

But has it actually worked?

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Social Brain Hypothesis

• Predicted group size for humans is ~150

• “Dunbar’s Number”

Monkeys

Apes

Neocortex volume divided by rest of brain

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The Natural Size of Human

Communities?

These all have mean sizes of 100-200

Neolithic villages 6500 BC 150-200 Modern armies (company) 180Hutterite communities 107‘Nebraska’ Amish parishes 113business organisation <200ideal church congregations <200Domesday Book villages [1087 AD] 150C18th English villages 160GoreTex Inc’s structure 150Research sub-disciplines 100-200

Small world experiments 134Hunter-Gatherer communities 148Xmas card networks 154

Maximum Network Size

350-374

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“Reverse”Small World Experiments

Hunter-Gatherer Societies

Xmas Card Networks

Individual Tribes

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HumanSocial Groups

These all have mean sizes of These all have mean sizes of 100-200100-200

Neolithic villages 6500 BC 150-200 Modern armies (company) 180Hutterite communities 107‘Nebraska’ Amish parishes 113business organisation <200ideal church congregations <200Doomsday Book villages 150C18th English villages 160GoreTex Inc’s structure 150Research sub-disciplines 100-200

Small world experiments 134Hunter-Gatherer communities 148Xmas card networks 154

Maximum Network Size

350-374

325-349

300-324

275-299

250-274

225-249

200-224

175-199

150-174

125-149

100-124

75-99

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25-49

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“Reverse”Small World Experiments

Killworth et al (1984)

Hunter-Gatherer Societies

Dunbar (1993)

Xmas Card NetworksHill & Dunbar

(2003)

Individual Tribes

Her 152 friends recorded for posterity…..?

http://www.youtube.com/watch?v=ApOWWb7Mqdo

Luckily, it’s a hoax….It was an advertising stunt!

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Is Your Online Network Bigger than ~150?

• Network size estimated from reciprocated exchanges

• # edges drops off after ~200

Gonzalez et al. (2011:PLoS-1) Haeter et al (2012: Phys. Rev. Letts)

Twitter Email

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Has Facebook Really Widened Your Social World?• It seems not….

• Modal number of ‘friends’ on Facebook = 150-250

• You may list 100s of friends, but you only talk to a handful

N 1 million Facebook users

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BUT….our friends are NOT all the same!

Our social world is less like this

…..and more like this

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Intimacy, Frequency and Trust

• Relationship between frequency of contact and intimacy

• Trust and obligation seem to be important

Emotional Closeness

109876543210

Me

an

Tim

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ince

La

st C

on

tact

(M

on

ths)

8

6

4

2

0

LOW Emotional Closeness HIGH

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The Fractal Periodicity of Human Group Sizes

Peak at=5.4

Peak at=5.2

Xmas Card Database

Social Groupings Database [N=60]

Scaling ratio = exp(2π/) = 3.2 and 3.3

Zhou, Sornette, Hill & Dunbar (2005)

Sizes of Hunter-Gatherer Groupings

Hamilton et al (2007)

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The Expanding Circles

Our relationships form a hierarchically inclusive

series of circles of increasing size

but decreasing intensity [ie quality of relationship]

We know all these layers exist

…and the military maintain the sequence far

beyond [to ~50,000]

5

15

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150

Intensity

EGO

500 1500

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The Military Model

Modern Army Organisation USA Australia

[1994] [2010]

Section 10 12Platoon 30 45Company 126 168Battalion 650 775Brigade/Regiment 4000 3750Division 12,500 15,000

War of Spanish Succession [1701-1714]

The need to solve two conflicting requirements:

Maximising cohesion and the number of boots-on-the-ground

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Network Structure on Facebook

• Facebook regional network in April 2008

• 3M nodes with 23M edges [useable dataset: 92,300 nodes]

• Density-based clustering: Optimal cluster structure is

4 layers

• Layer sizes correspond exactly to those found by Zhou et al. (2005) in F2F networks….with a scaling ratio of ~3….AND an added layer at 1.5

Cumulative size: 1.6 5.7 17.6 52.2Predicted size: (1.5) 5 15 50

Arnaboldi et al. (2012)

Optimal Cluster #

Support Sympathy Affinity ?? clique group group

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Network Structure on Twitter

• 205,000 human Twitter followers, 200M tweets

• Reciprocated postings

• Optimal # clusters = 4• Layers have same scaling ratio

[~3) and sizes virtually identical to theoretical layers

Facebook: 1.6 5.7 17.6 52.2

Theoretical: 1.5 5 15 50

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The Expanding Circles … as they really are

• It turns out, as predicted, that there really is an inner-inner layer at 1.5

• …perhaps because girls can have two intimate relationships (a best girlfriend PLUS a boyfriend)

….but boys can only manage one (a girlfriend or nothing)?

5

15

50

150

1.5

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Social Bonding Primate-Style

Primate social bonds seem to involve two distinct components:

An emotionally intense component

[= grooming endorphins]

A cognitive component [=brain size + cognition]

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• Best predictor of network size is orbitofrontal prefrontal cortex volume

• In a fine-grained VBM (voxel) analysis: best predictor of network size is ventromedial PFC

• 2 of 7 neuroimaging studies showing correlations between brain region volume and network size in humans and macaques

Friendship on the Brain?

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Importance of Time

Kin

0 9 18months

Friends

Change in Emotional Closeness Daily contact rates per person

Friendships decline rapidly in the absence of contact

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Time really is a Network Constraint

• Mobile phone dataset from 11 months [20M users and 9 billion calls]

• As network size [k] gets larger, o mean call rate asymptotes at ~200 o call diversity declines after a peak at

k≈15

Total calling is time is limited, and gets distributed more thinly

• There is a natural limit to network size, and it is set [in part] by how thinly social capital can be invested

Miritello et al. (2013)

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Just how consistent are these patterns?

An 18-month longitudinal study of 30 18-year-olds transitioning to University

….for whom we have complete call + text records and detailed relationship

questionnaires (at start, mid and end)

Roberts et al (2009), Roberts & Dunbar (2010a,b)

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Stability of Social Signatures

• Alters ranked by frequency of calls

• Ranking pattern remains similar across all three 6-mnth windowsDESPITE high turnover in in membership in successive 6-month windows [esp. in first interval as indicated by low Jaccard index – indexes similarity]

• 25% to top Alter 48% to top 3 Alters

Saramaki et al. (2014)

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Stability of

Social Signatures

• Comparison between 3 intervals

• Individual signatures are significantly more similar over time [dself] than they are to other individuals’ signatures [dref]

• Picture is identical using Emotional Closeness, duration of calls and # texts

Saramaki et al. (2014)

Ego 1

Ego 2

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Three Ways We Solved the

Bonding Problem

Millions Years BP

3.53.02.52.01.51.0.50.0-.5

Pre

dict

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room

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Tim

e (%

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50

40

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Laughter a cross-cultural trait

shared with chimpanzees

Music and dance

Religion and its rituals

Australopiths

Modern humans

H. erectus

Archaic humans\

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Something in the Way She Moves….?

• A study carried out in Brazil with very simple dance moves

Change in Pain Threshold

Self-in-Other Index

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Conclusions

• Human social networks are constrained by (1) cognition and (2) time

• The internet has increased the distance over which we can contact network members….

• BUT it has not increased the size or structure of our networks

• The real limitations [now] are:

o Lack of face-to-face interactiono Absence of endorphin-based bonding mechanisms

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Thanks ….!