Social Networks, Network Structures and Information Systems Part II: Homophily and Social Capital

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Lecture 10

• Social Networks, Network Structures and
  Information Systems Part II Homophily and Social
  Capital

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The power of social capital
1 1 2
Fully connected network N people, N(N-1)/2
ties Connections grow at a much faster
rate (quadratic vs. linear)
1 1 gt 2?
2 2 gt 4?
Bridge
6 6 gt 12?
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(No Transcript)
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Linking Social Capital and the Principle of
Homophily

• Two important concepts in structural arguments
  and network outcomes
• Social Capital
• Homophily

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Social Capital

• Networks as a resource access to information,
  goods, services.
• Cross-cutting social circles revisited
• The greater the number of intersecting social
  circles of which a node is a member, the greater
  the nodes social capital

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Simmel (1955) and Blau (1984) Cross-cutting
social circles
Circles can also be other categories i.e.,
political affiliations, religions, etc. They are
not necessarily well-defined groups.
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Homophily

• People interact more often with people who are
  like them than with people who are dissimilar.
• Age, gender, race/ethnicity, education, music
• We are a moving average of our associates.
  (Miller McPherson)

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Birds of a Feather Homophily in Social Networks

• Two types (Lazarsfeld and Merton 1954)
• Status Homophily
• Value Homophily
• Baseline and Inbreeding homophily
• Causes
• Structural Geography, Family, Organizational
  affiliations
• Cognitive Choosing to interact with similar
  others
• Common norms may bring individuals together with
  common attributes, and common attributes may lead
  to common norms

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Homogeny Vs. Homophily
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Information Flows and Structure

• Homophily affects the distribution and flow of
  information between individuals. It is a central
  part of understanding
• diffusion of Innovation
• distribution of cultural forms (music,
  religion, among others)
• information sharing and the distribution of
  knowledge through networks

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Example Music(Mark 1998)

• Music forms depend on people for their
  existence.
• Music types carve out niches in different
  sociodemographic segments of society.
• Music preferences are transmitted through network
  ties, which tend to be homophilous, leading to
  similar tastes among similar people.

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From Mark, 1998 Birds of a Feather Sing
Together Social Forces
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Homophily and Information Technology
Leskovec and Horvitz, Worldwide Buzz
Planetary-Scale Views on an Instant-Messaging
Network ftp//ftp.research.microsoft.com/pub/tr/TR
-2006-186.pdf
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What can we learn from studies like these?

• The processes do not appear to change so much
  over time (effects of weak ties, homophily), but
  systems like the Internetthe technology
  provides opportunities to connect on a wider
  range of dimensions.
• The structure of a given network can have
  significant effects on outcomes at the (a)
  individual and (b) aggregate level.
• Individual level Capacity to get/receive
  assistance, advice, help, resources.
• Aggregate level Regardless of individual
  efforts, the network structure in which a group
  of individuals are embedded can impact
  success/failure of some outcome(s).