Week 1: do contexts make networks? 1
Feld (1981) 1
Lorenz et al. (2020) – Social influence or selection? 3
Martinovic et al. (2009). Changes in immigrants' social integration during the stay in the host
country 5
Week 2 8
Milgram, S. (1967) The small world problem. 8
Watts, D. & Strogatz, S. (1998) Collective dynamics of ‘small-world’ networks. 9
Dodds et al (2003) An experimental study of search in a global social network. 11
Collins, J. & Chow, C. (1998) It’s a small world 13
Week 3 14
Mintz & Schwartz (1981) – Interlocking Directorates and Interest Group Formation 14
Cook, Emerson, Gillmore & Yamagishi (1983) – The Distribution of Power in Exchange
Networks 15
Savin-Williams (1979) – Dominance Hierarchies in Groups of Early Adolescents 18
Chase, Tovey, Spangler-Martin & Manfredonia (2002) – Individual Differences versus Social
Dynamics in the Formation of Animal Dominance Hierarchies 20
Week 5 21
Granovetter (1973) — "The Strength of Weak Ties" 21
Coleman (1988) — "Social Capital in the Creation of Human Capital" 24
Centola & Macy (2007) — "Complex Contagions and the Weakness of Long Ties" 27
Burt – The Social Capital of Structural Holes 29
Week 6 32
Harrigan & Yap (2017) — Avoidance in Negative Ties: Inhibiting Closure, Reciprocity, and
Homophily 34
Rubineau, Lim & Neblo (2019) — Low Status Rejection 37
Kros, Jaspers & Van Zalk (2021) — Avoidance, Antipathy, and Aggression 39
Week 7 42
Coleman, Katz & Menzel (1957) — The Diffusion of an Innovation Among Physicians 42
Christakis & Fowler (2007) — The Spread of Obesity in a Large Social Network over 32 Years44
Liu, King & Bearman (2010) — Social Influence and the Autism Epidemic 45
Centola (2010) — The Spread of Behavior in an Online Social Network Experiment 48
Week 8 50
Bond et al. (2012) — A 61-Million-Person Experiment in Social Influence and Political
Mobilization 50
Kramer, Guillory & Hancock (2014) — Experimental Evidence of Massive-Scale Emotional
Contagion Through Social Networks 52
Lewis, Gray & Meierhenrich (2014) — The Structure of Online Activism 54
Salganik, Dodds & Watts (2006) — Experimental Study of Inequality and Unpredictability in an
Artificial Cultural Market 56
,Week 1: do contexts make networks?
Feld (1981)
Research question
The paper seeks to explain why social networks exhibit specific structural properties, such as
clustering (high density) and transitivity (friend of a friend is a friend).
The central question is: How does the organization of social activities into "foci" constrain
and shape the formation and maintenance of social ties?
Feld specifically wants to challenge the idea that these network patterns are solely the result
of individual psychological preferences (like balance theory) by showing they can be
explained by the social structure of "foci."
Theory
The theory is based upon the idea that the relevant aspects of the social environment can be
seen as foci around which individuals organize their social relations. A focus is defined as a
social, psychological, legal, or physical entity around which joint activities are organized
(e.g., workplaces, voluntary organizations, hangouts, families, etc.). As a consequence of
interaction associated with their joint activities, individuals whose activities are organized
around the same focus will tend to become interpersonally tied and form a cluster.
1. Clustering: Social networks are not random; they consist of "clumps" of people with
many ties. According to Feld, clustering is the direct result of the organization of
activities into foci. Because a focus brings a limited group together and forces
interaction (constraints), a cluster forms automatically. It is a structural outcome, not a
psychological preference.
2. Opportunity: Individuals who share a focus have more opportunities to meet and
interact. Therefore, they are more likely to form a tie than individuals who do not
share a focus
3. Constraints: Foci constrain the set of potential associates (ties). You can only choose
friends from the people you actually meet.
‘The more constraining a foci is, the greater is the likelihood that 2 individuals in that
focus will be tied.’
● A foci always has a constraint; otherwise, there is no foci. In general, a smaller
foci has more constraint than a larger foci.
● High constraining foci have close-knit clusters.
4. Social reinforcement: interaction within a focus is often encouraged by the rules or
social norms of that specific setting.
5. Transitivity: If A is friends with B and A is friends with C, it is highly likely that
they all belong to the same focus. Because B and C are in that same focus, they are
constrained to interact. the focus provides the opportunity and the common ground,
making it very likely that B and C will also form a tie.
, 6. Density of personal networks: This refers to the extent to which an individual's
friends are friends with each other.
● If there is perfect transitivity, then all of an individual's friends know each
other, and the individual's network is completely dense. This is a highly
constraining focus On the other hand, if every tie is a local bridge, then none
of the individuals know each other, and the density is zero. The individuals
then has many low-constraining, non-overlapping foci.
● Multiplexity: when two individuals know each other through multiple foci.
This results in multifaceted relationships, which means the bond is deeper
because it is based on multiple areas of life. This significantly strengthens both
the constraint and the stability of the tie.
7. Local bridges: a local bridge is a tie between two people (A & B) who have no other
friends in common. These ties are crucial for the flow of information between
different groups (strength of weak ties (Granovetter)). Local bridges occur when two
people share a focus that is separate from their other foci.
● E.g., if A from group X and B from group Y both attend a very specific show
once a year, that show is the focus that creates a ‘local bridge’, otherwise A
and B (and therefore group X and Y) would stay disconnected
● When transitivity is perfect, local bridges don't exist because transitivity
requires every node to be tied to each other.
Conclusion
Social networks are not the result of individual choice, but a reflection of how society
organizes activities into foci. Social structure precedes and determines interpersonal ties.
Patterns like clustering and transitivity are logical consequences of the constraints within a
focus. To understand networks, you must look at the extra-network conditions (foci) that
bring people together.
Lecture: Balance theory
Balance theory is about the psychological drive for consistency in social relationships. It
explains transitive closure: if you are friends with Person A and Person B, those two are
likely to become friends with each other to create a "balanced" triangle. This process reduces
social tension and creates stable, cohesive groups.
Lorenz et al. (2020) – Social influence or selection?
Research Question:
The study investigates why friends in school often have similar educational expectations
(e.g., both wanting to go to university). The researchers aim to disentangle two competing
processes:
1. Selection: Do students choose friends who already have the same ambitions as they
do?
, 2. Social Influence: Do students change their own ambitions to match those of their
friends over time? This is crucial for understanding how social inequality is
maintained within the school system.
theory
The authors distinguish between two primary processes, each driven by specific
sociopsychological and structural mechanisms:
Social Selection (Homophily)
1. Homophily: adolescents tend to befriend others who are similar in salient characters,
like race, gender, ethnicity.
2. Secondary homophily: Even without a direct preference for similar expectations,
networks cluster because expectations overlap with other attributes like academic
performance, SES, and ethnicity. If students select friends based on these traits, they
indirectly sort by expectations.
Social network theory states that friendships are shaped by general, endogenous processes
that happen regardless of individual traits. These include:
● reciprocity: people tend to return a friendship nomination
● transitive closure: friends of friends are likely to become friends themselves
Transitivity specifically amplifies homophily because if your current friends already share
your educational expectations, befriending their friends—who likely share those same
traits—further increases the overall similarity within your social group.
Hypothesis 1: Adolescents are more likely to become and stay friends with peers who have
the same educational expectations than with other peers.
mechanisms of peer influence:
1. Social comparison: results in peer influence when adolescents evaluate their
educational goals through comparisons with others who provide a benchmark for
attitudes and behaviour. E.g., if friends have high expectations, the student perceives
these goals as "attainable" and "normal" for "people like us."
2. Social norms: Social interactions within social networks enforce social norms
regarding the value of education, which can affect students’ educational expectations
through peer pressure, peer rewards, and the exchange of information regarding the
importance of education. To maintain group cohesion and avoid being an "outlier,"
students adapt their expectations to the group mean.
3. provision of social capital: Peers provide resources. If peers have high expectations,
they provide knowledge about the "utility" of higher education and how to navigate
the system, which raises the actor's own expectations.
*Not all peers are relevant sources of social influence: friendship groups enable more
effective sanctioning of deviant behaviour than loose structures with weak ties. Information
about peers (the basis of social comparisons) varies according to the intensity of the contact
with these peers.
Feld (1981) 1
Lorenz et al. (2020) – Social influence or selection? 3
Martinovic et al. (2009). Changes in immigrants' social integration during the stay in the host
country 5
Week 2 8
Milgram, S. (1967) The small world problem. 8
Watts, D. & Strogatz, S. (1998) Collective dynamics of ‘small-world’ networks. 9
Dodds et al (2003) An experimental study of search in a global social network. 11
Collins, J. & Chow, C. (1998) It’s a small world 13
Week 3 14
Mintz & Schwartz (1981) – Interlocking Directorates and Interest Group Formation 14
Cook, Emerson, Gillmore & Yamagishi (1983) – The Distribution of Power in Exchange
Networks 15
Savin-Williams (1979) – Dominance Hierarchies in Groups of Early Adolescents 18
Chase, Tovey, Spangler-Martin & Manfredonia (2002) – Individual Differences versus Social
Dynamics in the Formation of Animal Dominance Hierarchies 20
Week 5 21
Granovetter (1973) — "The Strength of Weak Ties" 21
Coleman (1988) — "Social Capital in the Creation of Human Capital" 24
Centola & Macy (2007) — "Complex Contagions and the Weakness of Long Ties" 27
Burt – The Social Capital of Structural Holes 29
Week 6 32
Harrigan & Yap (2017) — Avoidance in Negative Ties: Inhibiting Closure, Reciprocity, and
Homophily 34
Rubineau, Lim & Neblo (2019) — Low Status Rejection 37
Kros, Jaspers & Van Zalk (2021) — Avoidance, Antipathy, and Aggression 39
Week 7 42
Coleman, Katz & Menzel (1957) — The Diffusion of an Innovation Among Physicians 42
Christakis & Fowler (2007) — The Spread of Obesity in a Large Social Network over 32 Years44
Liu, King & Bearman (2010) — Social Influence and the Autism Epidemic 45
Centola (2010) — The Spread of Behavior in an Online Social Network Experiment 48
Week 8 50
Bond et al. (2012) — A 61-Million-Person Experiment in Social Influence and Political
Mobilization 50
Kramer, Guillory & Hancock (2014) — Experimental Evidence of Massive-Scale Emotional
Contagion Through Social Networks 52
Lewis, Gray & Meierhenrich (2014) — The Structure of Online Activism 54
Salganik, Dodds & Watts (2006) — Experimental Study of Inequality and Unpredictability in an
Artificial Cultural Market 56
,Week 1: do contexts make networks?
Feld (1981)
Research question
The paper seeks to explain why social networks exhibit specific structural properties, such as
clustering (high density) and transitivity (friend of a friend is a friend).
The central question is: How does the organization of social activities into "foci" constrain
and shape the formation and maintenance of social ties?
Feld specifically wants to challenge the idea that these network patterns are solely the result
of individual psychological preferences (like balance theory) by showing they can be
explained by the social structure of "foci."
Theory
The theory is based upon the idea that the relevant aspects of the social environment can be
seen as foci around which individuals organize their social relations. A focus is defined as a
social, psychological, legal, or physical entity around which joint activities are organized
(e.g., workplaces, voluntary organizations, hangouts, families, etc.). As a consequence of
interaction associated with their joint activities, individuals whose activities are organized
around the same focus will tend to become interpersonally tied and form a cluster.
1. Clustering: Social networks are not random; they consist of "clumps" of people with
many ties. According to Feld, clustering is the direct result of the organization of
activities into foci. Because a focus brings a limited group together and forces
interaction (constraints), a cluster forms automatically. It is a structural outcome, not a
psychological preference.
2. Opportunity: Individuals who share a focus have more opportunities to meet and
interact. Therefore, they are more likely to form a tie than individuals who do not
share a focus
3. Constraints: Foci constrain the set of potential associates (ties). You can only choose
friends from the people you actually meet.
‘The more constraining a foci is, the greater is the likelihood that 2 individuals in that
focus will be tied.’
● A foci always has a constraint; otherwise, there is no foci. In general, a smaller
foci has more constraint than a larger foci.
● High constraining foci have close-knit clusters.
4. Social reinforcement: interaction within a focus is often encouraged by the rules or
social norms of that specific setting.
5. Transitivity: If A is friends with B and A is friends with C, it is highly likely that
they all belong to the same focus. Because B and C are in that same focus, they are
constrained to interact. the focus provides the opportunity and the common ground,
making it very likely that B and C will also form a tie.
, 6. Density of personal networks: This refers to the extent to which an individual's
friends are friends with each other.
● If there is perfect transitivity, then all of an individual's friends know each
other, and the individual's network is completely dense. This is a highly
constraining focus On the other hand, if every tie is a local bridge, then none
of the individuals know each other, and the density is zero. The individuals
then has many low-constraining, non-overlapping foci.
● Multiplexity: when two individuals know each other through multiple foci.
This results in multifaceted relationships, which means the bond is deeper
because it is based on multiple areas of life. This significantly strengthens both
the constraint and the stability of the tie.
7. Local bridges: a local bridge is a tie between two people (A & B) who have no other
friends in common. These ties are crucial for the flow of information between
different groups (strength of weak ties (Granovetter)). Local bridges occur when two
people share a focus that is separate from their other foci.
● E.g., if A from group X and B from group Y both attend a very specific show
once a year, that show is the focus that creates a ‘local bridge’, otherwise A
and B (and therefore group X and Y) would stay disconnected
● When transitivity is perfect, local bridges don't exist because transitivity
requires every node to be tied to each other.
Conclusion
Social networks are not the result of individual choice, but a reflection of how society
organizes activities into foci. Social structure precedes and determines interpersonal ties.
Patterns like clustering and transitivity are logical consequences of the constraints within a
focus. To understand networks, you must look at the extra-network conditions (foci) that
bring people together.
Lecture: Balance theory
Balance theory is about the psychological drive for consistency in social relationships. It
explains transitive closure: if you are friends with Person A and Person B, those two are
likely to become friends with each other to create a "balanced" triangle. This process reduces
social tension and creates stable, cohesive groups.
Lorenz et al. (2020) – Social influence or selection?
Research Question:
The study investigates why friends in school often have similar educational expectations
(e.g., both wanting to go to university). The researchers aim to disentangle two competing
processes:
1. Selection: Do students choose friends who already have the same ambitions as they
do?
, 2. Social Influence: Do students change their own ambitions to match those of their
friends over time? This is crucial for understanding how social inequality is
maintained within the school system.
theory
The authors distinguish between two primary processes, each driven by specific
sociopsychological and structural mechanisms:
Social Selection (Homophily)
1. Homophily: adolescents tend to befriend others who are similar in salient characters,
like race, gender, ethnicity.
2. Secondary homophily: Even without a direct preference for similar expectations,
networks cluster because expectations overlap with other attributes like academic
performance, SES, and ethnicity. If students select friends based on these traits, they
indirectly sort by expectations.
Social network theory states that friendships are shaped by general, endogenous processes
that happen regardless of individual traits. These include:
● reciprocity: people tend to return a friendship nomination
● transitive closure: friends of friends are likely to become friends themselves
Transitivity specifically amplifies homophily because if your current friends already share
your educational expectations, befriending their friends—who likely share those same
traits—further increases the overall similarity within your social group.
Hypothesis 1: Adolescents are more likely to become and stay friends with peers who have
the same educational expectations than with other peers.
mechanisms of peer influence:
1. Social comparison: results in peer influence when adolescents evaluate their
educational goals through comparisons with others who provide a benchmark for
attitudes and behaviour. E.g., if friends have high expectations, the student perceives
these goals as "attainable" and "normal" for "people like us."
2. Social norms: Social interactions within social networks enforce social norms
regarding the value of education, which can affect students’ educational expectations
through peer pressure, peer rewards, and the exchange of information regarding the
importance of education. To maintain group cohesion and avoid being an "outlier,"
students adapt their expectations to the group mean.
3. provision of social capital: Peers provide resources. If peers have high expectations,
they provide knowledge about the "utility" of higher education and how to navigate
the system, which raises the actor's own expectations.
*Not all peers are relevant sources of social influence: friendship groups enable more
effective sanctioning of deviant behaviour than loose structures with weak ties. Information
about peers (the basis of social comparisons) varies according to the intensity of the contact
with these peers.
