Friends and social networks

Strong and Weak Ties

Strong ties: Intense attachment Often reinforced by other ties

Weak ties: Acquaintances May link otherwise unconnected actors

Back to relationships and networks:

What produces (solidary) groups? (1) similarity/selection (2) influence (3) (inter-)dependence

Start with an interesting theory:

Balance theory simple theory of interaction generates ideal-types of social

structures can be tested against data

Balance Theory A theory of action Basic idea is that persons seek to avoid

tension or dissonance in their relations predicts that persons will change their

relations in order to avoid dissonance Scope conditions

Based on triads (groups of three) Assumes only positive (+) or negative (-)

relations Assumes symmetry of relations

Balance theory

Romeo

Juliet

Capulet

-

+

+

Unbalanced triad

Romeo

Juliet

Capulet

+

+

+

Balanced

Romeo

Juliet

Capulet

-

-

+

Balanced

Romeo

Juliet

Capulet

-

+

-

Balanced Balance theory

Balance and Transitivity

Balanced triads where no dissonance exists between members is called a transitive triad

Technical measure of transitivity: Triads are transitive if the product of

the sides is positive (+ x + x + = +; - x + x - = +)

Triads are intransitive if the product of the sides is negative (+ x + x - = -)

Balance theory

A

D

E

+

+

+

A

D

E

-

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+

Transitive Triads

A

D

E

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-

A

D

E

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+

+

Intransitive Triads

Balance theory

?

W. Virginia Caucus: On the 2nd round of balloting, McCain’s supporters voted for Huckabee

More on balance theory

Some cultural rules: The friend of a friend is a friend An enemy of my friend is my enemy The friend of my enemy is my enemy The enemy of my enemy is my friend

Balance theory

Can’t build a society from negative relations (things fall apart…)

A

D

E

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-

-

D

I

A B

E

C

G

J

F

H

But balance can produce groups

Balance theory

Trick: find the triads

Friends withEnemies with

+-

A

D

E+

+

+

A B

E

+

-

-

B

I

E

-

-

+

B

D

I

A

E

-

-

--+

++

+

Balance theory

Friends withEnemies with

Balanced Opposition

D

A B

E

C

G

J

F

H

Balance theory

I

Balance Theory and the Formation of Groups

In a world with only symmetric relations, we will find structures of balanced opposition (opposing solidary groups) “Us” and “them” Groups whose coherence comes from

Similarities to those within; and Difference from those outside

Real World examples of balanced opposition

Interpersonal relations Ethnic conflict Global alliances

Balance theory