LECTURE 11
Case Studies in Information Networks
Part I
Homophily and Network Ties: Religious
Switching (Cheshire 2000)
Triangles=High Racial Dissimilarity
Circles= Low Racial Dissimilarity
Structure of Interactions and Information Flow

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).
3
What’s a Core Network?





“Highly Salient Relationships”
Strong Ties
Homophilous Ties
High Density
Low Diversity
“core networks constitute
key sectors of routine interpersonal
environments that serve as primary loci of
interpersonal contact”
Network Structure & Social
Support in Non-routine Situations
Questions Addressed:
 How
do networks allocate
resources?
 How are core network ties
activated in non-routine
situations?
Questions NOT Addressed:
“Who gets what or how
much from different network
structures?”
 What were the outcomes?

5
The Influence of Core Networks
“individuals' experiences in core networks
produce "interpretive contexts" or
"frames" that condition individuals' responses
to nonroutine situations, through
their effects on individuals' routine experiences.”
‘Core’ Arguments
(Hurlbert, Haines and Beggs 2000)

Structure of core networks should affect allocation
of resources in two specific ways:
 Individuals
embedded in core networks that facilitate
support reception will activate a higher proportion of
their core network ties than those embedded in networks
that do not facilitate such support.
 Individuals
will receive a higher proportion of their
informal support from individuals inside, rather than
outside, their core networks.
Network Structure Hypotheses



Increased Density higher proportion of
core ties activated (and higher proportion
compared to those outside core)
Increased Size of Core higher
proportion of core ties activated (and
higher proportion compared to those
outside core)
Greater Geographic Dispersion  lower
proportion of core ties activated (and
lower proportion of informal support
providers coming from core)
Different Structures Affect Likelihood
of Tie Activation

Individuals who are embedded in higherdensity networks activate ties for informal
support better than those in lower-density
networks.
Low Density
High Density / Integrated
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Diversity and Tie Activation



Higher representation of men in core higher
proportion of activated core ties (and greater
proportion of informal support prividers will
come from core)
Older members of core  lower proportion of
activated core ties (and lower proportion of
informal support prividers will come from core)
Greater number of kin in core higher
proportion of activated core ties (and greater
proportion of informal support prividers will
come from core)
Different Structures Affect Likelihood
of Tie Activation

Greater gender diversity
also better activates ties
for informal support.
Different Structures Affect Likelihood
of Tie Activation

Greater proportions of
younger individuals, men, and
kin also better activates ties
for informal support.
Example of Social Support
Network of a Homeless
Woman (Mitchell 1994)
A Growing List…
So now we have at least 3 key issues about how,
when, and why individuals connect through social
networks:
1.
2.
3.
Weak / Strong Ties
Homophily
Core Networks & Informal Support
What are some of the implications for
designers of information systems?