sn- lecture 9

Social Capital & Network Characteristics

Lecture 9

Aims Lecture 9To understand:

To study characteristics of networks

Networks as social capital

The problem of only a structuralist approach+

+

+Homophily

Reciprocity

Centrality

Some Questions

Social network research requires general theories to answer:

In Network Research

Some Questions

Social network research requires general theories to answer:

Can the effects of networks (i.e., on behavior) be generalized across situations?

In Network Research

a.

Some Questions

Social network research requires general theories to answer:

Can the effects of networks (i.e., on behavior) be generalized across situations?

In Network Research

a.

Why certain network effects sometimes occur and sometimes not?b.

and if not,

i.e., Why is there more clustering in some networks than in others?

Structure & Social Capital

Structuralism

Structure overrides preferences

A first approach

You can explain people’s actions by only knowing the structure of their social network

Claims:

+

+

Structuralism

Structure overrides preferences

A first approach

You can explain people’s actions by only knowing the structure of their social network

Claims:

+

+

Give me the network & I will tell you what the actors will do

Selling Point

Labor markets (Granovetter, 1974)

Of this perspective

Illegal services: Abortion (Lee, 1969)

All markets:

+

+

Are socially organized in networks

Selling Point

Labor markets (Granovetter, 1974)

Of this perspective

Illegal services: Abortion (Lee, 1969)

All markets:

+

+

Are socially organized in networks

Role equivalence:Persons are tied not to the same persons but to similar persons

(Wasserman & Faust, 1994)

Selling Point

Labor markets (Granovetter, 1974)

Of this perspective

Illegal services: Abortion (Lee, 1969)

All markets:

+

+

Are socially organized in networks

Role equivalence:Persons are tied not to the same persons but to similar persons

(Wasserman & Faust, 1994)

Two positions in the aggregate: an elite person (well-connected) & a hanger-on (not well-connected)

Main ProblemsOf structuralism

It lacks a theory of individual behavior

Main Problems

Think about the micro-macro link

Of structuralism

It lacks a theory of individual behavior

+

Main Problems

Think about the micro-macro link

Of structuralism

It lacks a theory of individual behavior

+

Rational Choice Perspective:

Conceives networks as social resources

Main Problems

Think about the micro-macro link

Of structuralism

It lacks a theory of individual behavior

+

Rational Choice Perspective:

Personal networks can be treated as social capital that is instrumental in reaching our goals

Conceives networks as social resources

Not a new ideaSince Hobbe’s Leviathan:

Not a new idea

Thomas HobbesEnglish philosopher1588-1679

To have friends is to have power: for they are strengths united

Since Hobbe’s Leviathan:

Networks as Social Capital

Networks are treated as a specific resource important for most goals people have in life.

Networks as Social Capital

Two main propositions in S.C. Theory

Networks are treated as a specific resource important for most goals people have in life.

Networks as Social Capital

Two main propositions in S.C. Theory

Networks are treated as a specific resource important for most goals people have in life.

1 Social Resource Hypothesis: people better equipped with social capital will be better able to attain their goals

Networks as Social Capital

Two main propositions in S.C. Theory

Networks are treated as a specific resource important for most goals people have in life.

1 Social Resource Hypothesis: people better equipped with social capital will be better able to attain their goals

2 Investment Hypothesis: people will invest in social capital according to its instrumental value in producing their ends

Networks as S.C.It explains the emergence as well as the

effects of social networks

Networks as S.C.It explains the emergence as well as the

effects of social networks

A person’s social capital promotes her goal achievement

Networks as S.C.It explains the emergence as well as the

effects of social networks

She will invest in it depending on its instrumental value

&

A person’s social capital promotes her goal achievement

Networks as S.C.It explains the emergence as well as the

effects of social networks

Macro-micro link

She will invest in it depending on its instrumental value

&

A person’s social capital promotes her goal achievement

Networks as S.C.It explains the emergence as well as the

effects of social networks

Macro-micro link

She will invest in it depending on its instrumental valueMicro-macro link

&

A person’s social capital promotes her goal achievement

Homophily

Practical 11Choose links & Actions

Homophily

If instead of just looking at the network

We keep track of characteristics of the nodes (i.e., attributes)

Lazarsfeld & Merton (1954)

Homophily

If instead of just looking at the network

We keep track of characteristics of the nodes (i.e., attributes)

We tend to find that link nodes are similar to each other

Lazarsfeld & Merton (1954)

Homophily

If instead of just looking at the network

We keep track of characteristics of the nodes (i.e., attributes)

We tend to find that link nodes are similar to each other

Birds of a feather flock (will fly) together

Philemon Holland, 1960

Lazarsfeld & Merton (1954)

Real-life networksHomophily

Race & friendship networks US:

Interracial marriages US:

Gender & friendship networks

Real-life networksHomophily

Only 8% of people have any people of another race that they discuss important matters with (Marsden, 1987)

Race & friendship networks US:

Interracial marriages US:

Gender & friendship networks

Real-life networksHomophily

Only 8% of people have any people of another race that they discuss important matters with (Marsden, 1987)

Race & friendship networks US:

1% of white marriages, 5% of black marriages, 14% of asian marriages (Fryer, 2006)

Interracial marriages US:

Gender & friendship networks

Real-life networksHomophily

Only 8% of people have any people of another race that they discuss important matters with (Marsden, 1987)

Race & friendship networks US:

1% of white marriages, 5% of black marriages, 14% of asian marriages (Fryer, 2006)

Interracial marriages US:

Closest friends: 10% of men name a woman, 32% of women name a man (Verbrugge, 1977)

Gender & friendship networks

Real-life networksHomophily

Only 8% of people have any people of another race that they discuss important matters with (Marsden, 1987)

Race & friendship networks US:

1% of white marriages, 5% of black marriages, 14% of asian marriages (Fryer, 2006)

Interracial marriages US:

Closest friends: 10% of men name a woman, 32% of women name a man (Verbrugge, 1977)

Gender & friendship networks

In all cases lower than if ignoring attributes

Possible ExplanationsReasons for Homophily

Opportunity (Contact Theory):

Benefits/Costs:

Possible ExplanationsReasons for Homophily

The possibility that you meet people could be biased by attributes (i.e, race)

Opportunity (Contact Theory):

Benefits/Costs:

More of a chance of meeting your own type

Possible ExplanationsReasons for Homophily

The possibility that you meet people could be biased by attributes (i.e, race)

Opportunity (Contact Theory):

Benefits/Costs:

More of a chance of meeting your own type

Common attributes (i.e., language, culture, knowledge) make it easier

Possible ExplanationsReasons for Homophily

The possibility that you meet people could be biased by attributes (i.e, race)

Opportunity (Contact Theory):

Benefits/Costs:

Also social pressure or social competition

More of a chance of meeting your own type

Important:

Common attributes (i.e., language, culture, knowledge) make it easier

Possible ExplanationsReasons for Homophily

The possibility that you meet people could be biased by attributes (i.e, race)

Opportunity (Contact Theory):

Benefits/Costs:

Also social pressure or social competition

More of a chance of meeting your own type

Common attributes (i.e., language, culture, knowledge) make it easier

Important:

The structure of the network depends on the characteristics

i.e., why communication might circulate among one group and not another?

Quick Summarytwo points

From Structuralism:

From Homophily (Segregation Patterns):

Quick Summarytwo points

From Structuralism:

The characteristics of the network matter. They affect the individuals

From Homophily (Segregation Patterns):

Quick Summarytwo points

From Structuralism:

The characteristics of the network matter. They affect the individuals

From Homophily (Segregation Patterns):

The characteristics of the individuals matter. They affect the structure of the network

Reciprocity

ReciprocityLocal Patterns

ReciprocityLocal Patterns

Directed Networks

ReciprocityLocal Patterns

Directed Networks

A node can be linked to another without the second being linked to the first (i.e., webpages)

ReciprocityLocal Patterns

Directed Networks

A node can be linked to another without the second being linked to the first (i.e., webpages)

ij in g does not imply ji in g

ReciprocityLocal Patterns

Directed Networks

A node can be linked to another without the second being linked to the first (i.e., webpages)

Reciprocity

There is a tendency to dyadic reciprocation in most directed networks

ij in g does not imply ji in g

ReciprocityLocal Patterns

Directed Networks

A node can be linked to another without the second being linked to the first (i.e., webpages)

Reciprocity

There is a tendency to dyadic reciprocation in most directed networks

ij in g does not imply ji in g

if ij in g it is more likely ji in g

ReciprocityExplanation

ReciprocityExplanation

Mutual Dependence

ReciprocityExplanation

Mutual DependenceActors (i.e., players, people) depend on each other for valued outcomes, and benefits will be received from another actor only if they are also given in return

(Emerson, 1972)

ReciprocityExplanation

Mutual DependenceActors (i.e., players, people) depend on each other for valued outcomes, and benefits will be received from another actor only if they are also given in return

Think aboutCooperation: if relations are not reciprocated they are likely to be terminated more rapidly

(Emerson, 1972)

ReciprocityExplanation

Mutual DependenceActors (i.e., players, people) depend on each other for valued outcomes, and benefits will be received from another actor only if they are also given in return

Think aboutCooperation: if relations are not reciprocated they are likely to be terminated more rapidly

(Emerson, 1972)

Keeping a non-reciprocated relation implies status deference

tend to be eliminated

Node Centrality

Node CentralityPositions in Networks

Node CentralityPositions in Networks

Who are influential, powerful (Think of our Facebook Example with Ana)

How different nodes are positioned in the network?

Node CentralityPositions in Networks

Who are influential, powerful (Think of our Facebook Example with Ana)

How different nodes are positioned in the network?

Many social networks show a fair extent of centralization

Node CentralityPositions in Networks

Who are influential, powerful (Think of our Facebook Example with Ana)

How different nodes are positioned in the network?

Many social networks show a fair extent of centralizationdifferentiation between social actors with

respect to their centrality

Node CentralityExample

Ways of measuring centrality

Node Centrality

2

1 4

1 24

1 3

3 2

3 2

2

2

Example

Ways of measuring centrality

Node Centrality

2

1 4

1 24

1 3

3 2

3 2

2

2

Both white nodes have degree 2 (degree centrality)

The first seems more central - neighbors (3) & (4): (betweenness)

Better connected in another sense

Example

Ways of measuring centrality

Node Centrality

2

1 4

1 24

1 3

3 2

3 2

2

2

There are many other measures of centrality

Both white nodes have degree 2 (degree centrality)

The first seems more central - neighbors (3) & (4): (betweeness)

Better connected in another sense

Example

Ways of measuring centrality

Node CentralityWhy do we observe it?

It reflects social organization and opportunities

Node CentralityWhy do we observe it?

It reflects social organization and opportunitiesA strongly centralized network increases the likelihood of collective action in mobilizations - easier contact to others

(Marwell, Oliver & Prahl, 1988)

Node CentralityWhy do we observe it?

Result of feedback processesFavoring the creation of links to nodes that are already highly connected

It reflects social organization and opportunitiesA strongly centralized network increases the likelihood of collective action in mobilizations - easier contact to others

(Marwell, Oliver & Prahl, 1988)

Node CentralityWhy do we observe it?

Result of feedback processesFavoring the creation of links to nodes that are already highly connected

It reflects social organization and opportunitiesA strongly centralized network increases the likelihood of collective action in mobilizations - easier contact to others

(Marwell, Oliver & Prahl, 1988)

Unto him that hath is given and from him that hath not is taken away, even that which he hath

The Matthew effect (Merton, 1968)

Node CentralityWhy do we observe it?

Result of feedback processesFavoring the creation of links to nodes that are already highly connected

It reflects social organization and opportunitiesA strongly centralized network increases the likelihood of collective action in mobilizations - easier contact to others

(Marwell, Oliver & Prahl, 1988)

Unto him that hath is given and from him that hath not is taken away, even that which he hath

The Matthew effect (Merton, 1968)

However, centralization is most likely in physical networks: Internet hubs

Checklist

Both structure of the network & individual behavior (and characteristics) influence each other

Checklist

Both structure of the network & individual behavior (and characteristics) influence each other

Checklist

People use their social networks as a form of capital that helps them achieve what they want

Checklist

People use their social networks as a form of capital that helps them achieve what they want

Social networks portray different properties:

Both structure of the network & individual behavior (and characteristics) influence each other

Checklist

People use their social networks as a form of capital that helps them achieve what they want

Social networks portray different properties:

Individuals with common traits are likely to be related (Homophily)

Most relationships are reciprocal (both parts aim for it)

We can look locally at who is influential (centrality)Important for diffusion of information

Both structure of the network & individual behavior (and characteristics) influence each other

Questions?