Social networks

Question 1

What are nodes & edges?

Answer 1

What are nodes?
* Entities aka actors
* When we’re talking about social networks, actors consist of persons (i.e. pupils, workers in a firm, etc)

What are edges?
* Ties between them
* Connections in form of i.e. friendships, collaboration, bullying, exploitation, etc.

But can be much more complex/mathematical: nodes could be words that are used in a language & edges the frequency of how often they co-occur

Question 2

What are paths?

Answer 2

The different ways through a network that follow ties along certain nodes

Question 3

Directed / indirected networks

Answer 3

• Directed = friendship (directed arrow connecting the nodes)
• Undirected = relatives (no sense to use direction)

Question 4

Why study social networks?

Answer 4

• Empirically important: provide the base for a lot of different social processes, e.g. transmission of infection/disease or opinion dynamics (who is able to make his opinion the dominant one), polarization or cultural change - gender roles diffusing through population
• Socially fascinating: Immediately at the core of sociology, not about action theories of individuals but social structure right away (no identity issue, identity still important: norms, roles, etc) but with networks you’re already at the macro level + if studied over time, one can also look at the dynamics - how does network change
• Methodologically different: compared to standard regression models and normal data collection methods (i.e. Allbus survey), where data is collected on the individual level + also randomly selected (ideally no relation with each other)  with network analysis it is tried relatively early on to retain social structure so it is examined much more direct manner

Question 5

What kind of problems do we encounter when studying SN?

Answer 5

1. Statistical problem later on as not randomly sampled - error is not IID (independently & identically) + a lot of confounders as it is very difficult to capture everything that goes on between the nodes  one has to control for every relevant mechanism and maybe even look beyond bounded network, always the risk of some unobserved source of correlation that biases our estimate
2. “Theory Gap” - Granovetter (1979):
   - Rapidly expanding literature on “social networks” BUT where is theoretical underpinning? Most of them are constructed on theoretical vacuum -> network theories tend to be rather technical
   - Flap & Völker 2013: base of network theory is just an orienting statement “the structure of social networks determines the action of network members”
   - Some people even say it is only about methods, no place in sociological theory -> Kroneberg critique: wrong bc social mechanisms in networks analysis very important

Question 6

Egocentric Network Analysis

Interest

Answer 6

Interested in collecting data on personal networks of individuals, i.e.support network of elderly people or new immigrants

Question 7

Egocentric Network Analysis

theoretical framework

Answer 7

More generally, a version of social capital theory deals with ties that are of value to us/ help us to attain our goals (Flap & Völker 2013)

2 hypothesis which often guide egocentric network analysis as a theoretical framework

• Social resource hypothesis: People better equipped with social capital will be better able to attain their goals
• Investment hypothesis: Therefore, people are ready to invest in social capital according to its instrumental value in producing their ends

Question 8

Egocentric Network Analysis

What do we do in ENA?

Answer 8

Try to reconstruct the network of particular respondent’s ego (can be random sampled)

(1) Name-Generator

• Respondents are asked to give names of people who are most important to them, who they know, know by sight, etc. -> hierarchical levels of acquaintanceship
• Not every survey has these kinds of questions bc they take a lot of time (Side fact: study of close ties in the US, evidence suggested that people had fewer ties, but one of the reasons was that the respondents did not want to engage in this time-intensive activity again so they just told them about less people)
• Typical size around 50 (close-and-active network) but sometimes also valuable to look even beyond personal network (150), especially if interested in social capital: it is those weak ties where you get interesting information, usually in support group information u get is redundant

(2) Position-Generator

• You ask: Think about lawyer, physician, data scientist, whatever - do you know someone in this position?  much more effective, especially when it comes to Social Capital

Question 9

Sociocentric Network Analysis

Interest

Answer 9

• Data on all ties within a bounded setting i.e. gossip ties in company or friendship ties in school class (egocentric approach cannot tell you who is friends with each other, only who you consider your friends or your view on these bonds)
• Egos are not sampled randomly, but one tries to capture the whole bounded network

Question 10

Sociocentric Network Analysis

Problems

Answer 10

• Boundary problem: What is the relevant setting? Where does is end? (i.e. friendships only within one class or should we look at parallel classes as well? The one below? The one above? Only academic context or neighborhood?)
• Non-response: At least 80% of network needs to participate otherwise too much missing

Question 11

Sociocentric Network Analysis

Why is complete/socio-network analysis so promising?

Answer 11

• Main advantage: information on not only who is selected as network partner by whom BUT ALSO could have a tie but don’t - the absence of ties, ties that did not form  reconstruct choices that underlie the social network
• Example: no tie bc no lawyer present in the network or no tie although there are lawyers present - completely different explanations - egocentric approach could not tell

Question 12

Basic mechanisms of tie formation

Stadtfeld/Amati (2021)

Answer 12

1. Transitivity = Triadic closure: a third tie builds between the first and last node (i.e. sharing a friend)
2. Popularity = likely to receive more ties when already has a lot of ties
3. Activity vs Attraction (opposites)
4. Homophily
   * selection mechanism based on certain shared attributes i.e. both are boys, sociologists which makes them share a tie, they assume that it is more rewarding (“gleiches und gleiches gesellt sich gern”)
   * of great interest bc related to social cohesion & segregation, strong homophily = people prefer similar people  fragmentation of society
   * not an iron law, also heterophily possible, more likely to connect with someone who is different (exchange relations, better if specialized in different areas, i.e. “classical family”, men = labor, women = children)
   * sometimes difficult to tell whether homophily (friends bc we are both criminal) or social influence (friends before and then I became criminal bc you are)  longitudinal data to tell apart

Question 13

Basic mechanisms of tie formation

Gremmen et al. 2017

Answer 13

Question 14

Why network evolution interesting?

Answer 14

• Intrinsic interest: i.e. Is social cohesion declining? Or Do networks become more segregated?
• Base for causal inference: “why does it look how it looks?” - understanding the underlying mechanisms of tie formation

Question 15

How do we analyze network evolution?

Answer 15

• Most prominent approach = Stochastic actor-oriented models (SAOM) for dynamic networks (Snijders et al. 2010) aka longitudinal data
• Basic idea: observing a model at two different time points (i.e. school class friendships) - going there maybe every 3 months - how do we get from state A to state B?
• Goal: model the evolution of the network between these time points
• Assumptions:

1) Really requires longitudinal data
2) Time is modelles as continuous-time process, changes can happen at any time
3) Individuals (nodes) decide whether to form a tie or not (behavioral model)
4) Only 1 tie change at a time –> big changes are due to small changes
5) some changes will be random

Question 16

SAOMs - Actor-oriented element:

Answer 16

• reconstructs the choices that actors make, every actor can make a choice if it’s his/her turn whether to
  1. dissolve tie (i.e. unfriend a certain person)
  2. create a new tie (i.e. new friend)
  3. do nothing

(then another actor is chosen and so on)

Question 17

SAOMs

why quantitative approach

Answer 17

• How attractive is it to reciprocate a friendship tie with someone else? Or to befriend a friend’s friend? –> then we infer from the data that there is a tendency for reciprocation, triadic closures, etc.
• Not qualitative by asking but quantitative by reconstructing the mechanisms

Question 18

SAOMS - The objective (utility) function

Answer 18

• models the attractiveness of network states x to actor i that are reachable in one step from the current network
• modelled like multinomial logistic regression (not a binary choice but the choice to form/un-form ties with everyone in the network)
• Parameters ßk express whether a feature of i’s neighborhood is desired or adverted, i.e. I like to have many reciprocated friendship ties or I like to have close triades -> ßk will be positive; if you don’t like to form those -> ßk negative = a way to estimate these tie-formation tendencies from the data

also possible to capture homophily: No. of friends who behave violently -> If violent class mates are more likely to be nominated as friends (over time) -> seems that students befriend violent people (but could also be the other way around)

Question 19

Example: group-specific attractiveness of violent peers as friends

why difficult

Answer 19

Sometimes questions like “Do boys prefer rough, violent ties?” arise

1) so, objective function has to account for whether alter (different classmate) engages in violence and whether they are desired/avoided as friends
2) And even if tie formed from stage 1 to 2:
attractive du eto violent behavior or different reason? i.e. blue node = common friend (blue node), homophily (both red)

• If interested as a researcher to answer this question -> statistically control for other tendencies (needs to include all the other relevant mechanisms)
• This means: Causal interpretation requires strong assumption of unconfoundedness -> evidence is correlational data!

Question 20

How to differentiate: Selection (Homophily) or Influence?

Answer 20

• Method: Not only a model for stochastic actor orientation but also one for how behavior changes over time, like two regression equation, one is the objective one (do I connect with others as friend) but also another one (do I start smoking)
• If u observe a correlation between network and individual characteristics -> at least 2 competing mechanisms:
  1. Social influence: Network leads to behavioral alignment
  2. Homophily: Actors’ behavior leads to network alignment
• great ambition of these models is to tell those apart –> Caution: Subscribe to a lot of assumptions with these models as validity of results obtained by modeling is conditional on having all the relevant variables inside model specification

Question 21

Multilevel network analysis

interest & advantages

Answer 21

• Multiple complete networks, i.e. not only interested in one school but 1000 schools
• Advantage of multilevel:
  1. Allows scholars to study how characteristics of contexts may affect the operation of particular tie-formation mechanisms
  2. Students of different ethnic groups, when is ethnic segregation stronger, what are the contextual characteristics of schools, also implying, how can we change those characteristics so that there is less segregation
• BUT sometimes, also important to just look at one network bc intrinsically extremely important (i.e. trade relationships of nations)

Question 22

Theoretical background of study by Small & Sukhu

Answer 22

• How do people acquire social resources? How and when do persons invest in others? What is the exact mechanism underlying these investments? (might there be different ways than looking at it as of instrumental value?)
• Standard view: Perry & Pescosolido 2010: “Functional specificity” hypothesis:
  “Individuals engage in selective and purposive activation of ties”, they “engage in problem- or task-specific activation of social network ties, evaluating who in their networks in most willing and able to fulfill a particular need for support or companionship” (Perry & Pescosolido 2010: 356) –> u have a broken washing machine, so u wonder is there someone in the neighborhood available to help u fix the problem
• 3 step process:
  1. Seek: I need support, rather then fixinf it on my own and making it perhaps worse, decision to seek support
  2. Select: Who will be best and willing, selecting some alter in your network
  3. Activate: Call or ask the person

Question 23

Critism of Small and Sukhu

Answer 23

• Not always so deliberate of a choice, maybe just someone who was available/accessible (i.e. if the printer broke u don’t call the printer company but rather talk to the next best available maybe even just a random person in the room)
• Could also be that one decides to not do anything about it and just leave the room in a frustrated manner, but someone else just enters it and so u think hm ok maybe I just ask him/her  so not a consecutive process but almost simultaneously, not distinct decisions but opportunity created the idea (if greater effort, probably less spontaneous)
• Also, iterative process, not a one-shot process, maybe need to ask a couple of people
• One-sided view from the perspective of support seeker, but could also be analyzed from perspective of support giver (i.e. self-initiation, etc)

Question 24

Empirical study of Small & Sukhu 2016

Setup

Answer 24

• Survey of 2000 college students across US, which they asked how they sought help around three forms of everyday social support. It asked them consider the last time they sought help with a
  1. Mathematics or economics problem
  2. Paper they were writing
  3. and with a roommate problem
• Over the previous year, 71.2% had sought help with a mathematics or economics problem; 57.6%, with a paper; 42.1%, with a roommate. The subset of respondents who sought help on at least one of these problems constitutes our analytical sample.

Question 25

Empirical study of Small & Sukhu 2016

Result

Answer 25

• We have found evidence consistent with this standard process (seek, select, activate) when skill and trustworthiness played a major role in the decision, but inconsistent when accessibility did. In the latter circumstances, one of two different processes was at play—either incidental or spontaneous activation, both of which are responsive to context and opportunity

Question 26

“Who is fighting with whom? How ethnic origin shapes friendship, dislike, and physical violence relations in German secondary schools” - Mark Wittek & Kroneberg

purpose

Answer 26

Previous work assumes a “dark side” of ethnic segregation in friendship networks as a possible symptom or cause of threat perceptions and hostile inter-group relations

Walsh et al. (2016) study that builds on this assumption:

• studied immigrant school composition, classmate support and involvement in fighting
• finding: positively related (more immigrants, more negative ties like fighting and bullying)
• explanation: Integrative Threat Theory & Social Identity Theory = high number of immigrants -> greater tension between pupils enabling greater ingroup/outgroup competition (if only a small number, they don’t have the opportunity to meet/group with each other, forced to more cross-ethnic groups) which might be associated with fighting and tension occurring on an intergroup basis
• Problem: they simply looked at how many fights/have been victimized, but not who fought who, was it even someone from a different ethnic group? So, the underlying misconceptions originate not only in a lack of (network) data, but also in a failure to theorize violence relations based on theories of action (“when do people fight each other”)

Question 27

Importance of distinguishing different types of (neg.) ties

Answer 27

Dislike
* Relational cognition
* Affective evaluation = very low cost, u can just say u don’t like someone

Physical violence:
* Relational behavior
* Quite rare (even in life of offenders) bc high risk & costs

So, what is more common between friends?
* Physical violence (is rare but) more common between friends (in adolescence), as driven by frequency of contact and exposure in unsupervised settings, always high risk but less risky if u know the person (i.e. know their strength, limits, connections) + opportunity structures in favor of friends bc they spent time outside of class/school
* Dislike rarer among friends, if u dislike someone u just avoid them

Question 28

“Who is fighting with whom? How ethnic origin shapes friendship, dislike, and physical violence relations in German secondary schools” - Mark Wittek & Kroneberg

Method

Answer 28

Exponential Random Graph Models (ERGMs)
* good for cross-sectional data
* not actor-oriented, simpler: the whole network structure is treated as the outcome/dependent variable & look at whether same ethnic ties are more frequent than chance would dictate - controlling for other mechanisms
* Structuring effects: i.e. same school class, same gender -> So, you’re estimating whether the existence of a tie depends on the attributes of the involved actors (ego and alter) and on certain (local) network structures/mechanisms (= interdependence)

-> ERGMs infer the existence of an underlying local process (e.g., triadic closure, ethnic homophily) from the prevalence of its respective local structure controlling for other relevant local structures

Question 29

“Who is fighting with whom? How ethnic origin shapes friendship, dislike, and physical violence relations in German secondary schools” - Mark Wittek & Kroneberg

Main findings (1)

Answer 29

Dislike & violence are very different negative ties & very differently related to friendships

• friendship & dislike: do not go together, no dislike in the shortest path distance, dislike rather people that are further away, maybe they are nice I just don’t know them or they are stupid and so I avoid them
• friendship & violence: reverse relationship, most likely the closer u are and less likely the further away a person is –> Still very rare, 20% of violent acts are between friends, but only 5% of friendship ties that characterize as violent

Question 30

What is ethnic homophily and why is it problematic?

Answer 30

What is it?
- Preference for same-ethnic others
- You must control for a other shared characteristics (i.e. gender, group sizte, etc.) and all other mechanisms tho, only then ethnic net segregation (= ethnic homophily)  indirect way to measure ethnic preferences

If it is ethnic homophily, this might be problematic:
1. hindering the reduction of inter-ethnic prejudice (symptom)
2. triggering by feelings of threat or superiority (cause)
3. increasing the likelihood of victimization by out-group members

Question 31

“Who is fighting with whom? How ethnic origin shapes friendship, dislike, and physical violence relations in German secondary schools” - Mark Wittek & Kroneberg

Main findings (2)

Answer 31

Ethnic origin plays a different role for dislike and violence
Across schools,

• relative tendency to dislike ethnic outgroup members (ethnic heterophobia)
• relative tendency for violence among same-ethnic peers

So, the idea of inter-ethnic fights simply wrong, problem that maybe not the same ethnic cleavage as in adult societies but school life not simply a mirror

Question 32

“Who is fighting with whom? How ethnic origin shapes friendship, dislike, and physical violence relations in German secondary schools” - Mark Wittek & Kroneberg

Main findings (3)

Answer 32

We should re-think intergroup violence and ethnic friendship segregation in the school context

• Connected ethnic homophily (how segregated) with tendency to fight within groups: the more segregated the friendships are, the more fighting happens within groups, so, if ethnic groups don’t have ethnic outgroup friends, they fight with each other
• If there is more fighting between ethnic groups maybe a good sign? Could indicate high degree of integratedness

Question 33

“Who is fighting with whom? How ethnic origin shapes friendship, dislike, and physical violence relations in German secondary schools” - Mark Wittek & Kroneberg

Conclusion

Answer 33

1. Dislike and violence are very different “negative ties”, as criminology and action theory suggest!
2. Ethnic origin plays a markedly different role for different types of negative ties (sentiments vs. physical confrontation)
3. The tendency for violence to occur more often within ethnic groups is partially due to social closeness
4. Ethnic homophily in friendships is not necessarily indicative of inter-ethnic hostility or violence

Question 34

“Beyond and Below Racial Homophily: ERG Models of a Friendship Network Documented on Facebook.” - Wimmer, Andreas / Kevin Lewis (2010)

Answer 34

• Based on Facebook data, used for example memberships in clubs (i.e. national origin club)
• Common view to look at everything between racial groups, but is it the relevant level? Sometimes necessary to look beyond, could be important not that they are both Asians, but that they both listen to Hip hop -> Wimmer yielded a “deethnicized” research design, makes sense to think about how people characterize themselves and others, research needs to be open beyond ethnic categories

(homophily estimates: the bigger the circle, the bigger the group, the higher the amplitude, the stronger the homophily)

Question 35

Closing words: social networks

Answer 35

• In regard to Granovetter’s theory gap, some truth in that many network models are constructed in a theoretical vacuum, each on its own terms, and without reference to a broader or common framework but not necessary that network researchers need to develop their own theoretical framework -> can benefit from other theories (e.g., dual processes, ethnic boundary making, opportunity theories)
• It may be wrong and dangerous to aim at a completely autonomous theoretical foundation of social network analysis