This document discusses how social networks and relationships change over time. It covers two main ways time is incorporated: 1) how things like ideas diffuse through a network, and 2) how the network structure itself changes as relationships are formed or break. It also discusses different forces that can impact network dynamics, such as reciprocity, transitivity, balance, and structural holes. Simulation models are described that examine how simple rules about seeking transitivity or avoiding conflict can lead to the formation of cliques or more fluid network structures over time.

1. Time and Social Networks

7. Dyadic Forces

9. Enemy of my Friend is an Enemy B A C

10. Friend of my Enemy is an Enemy B A C

11. Enemy of my Friend is an Enemy B A C

12. Enemy of my Enemy is a Friend B A C

14. Closure Force

15. Closure Force

16. Structural Holes

17. Structural Hole Force

18. Hierarchy

22. Time 1

23. Time 5

24. Time 10

25. Reciprocity

26. Transitivity

28. Structural (im)balance 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 9 11 13 15 17 Extent of Structural Imbalance Structural Imbalance Generalized Imbalance Week

30. Doreian, Kapuscinski, Krackhardt & Szczypula: A brief history of balance through time. “… the micro-level processes can be viewed as generating social forces that move the structure toward group balance.” … negative ties within groups are likely less tolerated than positive ties between groups, as negatives within group may threaten the group in ways that positive ties between groups do not.

31. An extension: A balance model of friendship change among adolescents The basic hypothesis of social balance is that people will make choices that bring the entire group into balance. But, consider how a given relationship looks from different perspectives: A transition that generates transitivity for one person can generate intransitivity for another. As such, there is no guarantee that friendship change will result in a globally balanced outcome.

32. State-Transition diagram of triads

33. Testing in simulation What are the implications for relationship change if people follow transitivity, from their own point of view? J. Moody used a simulation, based on data from Add Health, to answer this question. Rules: For every agent, Attempt to achieve closure Attempt to achieve transitivity Resolved through adding and dropping edges

34. Strong transitive and intransitive rules: Results in cliques forming quickly and maintaining over time.

35. Moderate values for seeking transitivity and avoiding intransitivity: Results in a fluid network structure.

43. ...dissonance causes action

44. Can Conflict Spread?

45. Can Conflict Spread?

46. The greater the network density, the greater is the probability of a catastrophic cascade

47. Like the forest fire?

48. Phase Transition #2

49. alpha = 1.2886

50. Degree Distribution