1. Friends and social networks

2. Announcements Treat Local and Cosmopolitan Networks Small Worlds (Milgram, Watts) Weak Ties (Granovetter)

3. Not functi onal 1 Minim al Functi on 2 Functi onal/n ot maste red 3 Functi onal/m inor proble ms 4 Full success 5 Clear identification of individual factors Clear identification of supra-individual factors Discussion of inter-play between individual and social factors Appropriate use of empirical evidence, concepts, and or readings Readability (top-down organization, good use of headings, clear sentences, no confusing passages) Grammar and syntactical correctness (scored, but not included in final grade)

4. Groups in Crowds

5. Primary Groups Groups whose members have close and intimate emotional attachment to one another and to the group (strong sense of solidarity, loyalty) Classic example: families Characteristic of gemeinschaft

6. Network Structure of Primary Groups Strong ties Redundant ties (multiple paths connecting nodes) Direct-person to person interaction Frequent interaction Clustered geographically (local) Self-contained

7. Significance of primary groups Members of groups characterized by strong and overlapping internal ties are likely to: –Share norms and beliefs –Trust each other –Recognize interdependence –Recognize each other as members of the same group

8. Secondary groups Groups whose members have only limited emotional attachment to one another, and weaker sense of belonging to a ‘group’ (weaker solidarity, little loyalty) Classic examples: co-workers, members of a secondary association Characteristic of gesellschaft

9. Network Structure of Secondary Groups Full of ‘holes’ Weaker ties Scattered geographically Less face-to-face interaction

10. “Local”– Solidarity Emotional comfort Strong monitoring capacity (strong influence) isolated “Cosmopolitan” less solidarity Less conformity Access to more information Local and Cosmopolitan nets

11. How small are our worlds? Does person x know person y? Are they a ‘friend of a friend’? Why are we surprised to run into someone who knows someone we know?

12. “Worst Case” Scenario

13. Travers and Milgram experiment How could person x get in touch with person y? Task: Get a letter to an arbitrary “target”: Boston Stockbroker Randomly selected sample in Nebraska (included some stockbrokers) Randomly selected sample in Boston Total sample = 296 217 sent it onto friends 64 reached target (29%) Average chain length: about six steps!

14. Findings Many used geographic information to move letter, then it circled around for a while Many tried to get the letter to someone they new in the financial industry Men had shorter chains than women

15. Small World Number Average number of steps, (jumps, links) between two people In general, lower for people with higher social status Though women have more friends than men, historically have tended to be more disconnected from the world

16. Clusters Bridges Small World Network

17. Features of Small Worlds Balance sense of community with access to information

18. Strength of Weak Ties Weak ties are very important for spreading information Less effective at exerting influence Weak tie (bridge)

19. Strong and Weak Ties Strong ties: Intense attachment Often reinforced by other ties Weak ties: Acquaintances May link otherwise unconnected actors