1. THE EMERGENCE OF COLLECTIVE MEMORIES Sungmin Lee Verónica Ramenzoni Petter Holme http://www.tp.umu.se/~holm e/

2. Petter@DPG I became interested in a science career discrete mathemati cs (my collaborator) Fredrik Liljeros decided to come here complex network boom of early 00’s (my office mate) Martin Rosvall was invited Narrative network / memory web

3. Outline

4. Empirical memory web Source material Bearman, Moody, Faris, 2003. “Networks and History” Complexity 8:61–71.

5. Empirical memory web Individual memory web 1 Bearman, Moody, Faris, 2003. “Networks and History” Complexity 8:61–71.

6. Empirical memory web Individual memory web 2 Bearman, Moody, Faris, 2003. “Networks and History” Complexity 8:61–71.

7. Empirical memory web Aggregate memory web Bearman, Moody, Faris, 2003. “Networks and History” Complexity 8:61–71.

8. Empirical memory web Degree distribution

9. Empirical memory web Community structure

10. Model ingredients

11. Communication model Learning dynamics

12. Example output Memory overlap, Jaccard index of associative arcs

13. Model community structure Number of groups

14. Model community structure Memories and social ties

15. 15 Model community structure Size- & communication-rate scaling of the number of communities

16. Model community structure Size-scaling of the diversity regime

17. Model community structure Size-scaling of the number of groups

18. Summary

19. Vielen Dank! to all of you … from http://www.tp.umu.se/~holme /

20. Empirical memory web Clustering coefficient vs. degree

21. Empirical memory web Degree correlations

22. Communication model Community structure

23. Communication model Errors & misinterpretations

24. Model community structure Why a peak in g?

25. Model community structure Size-scaling of the diversity regime