Wang,C.J.(2011).The Emergence of Spiral of Silence from Individual behaviors: Agent-based Modeling of the Spiral of Silence. Paper presented at The 64th Annual Conference of the World Association for Public Opinion Research (WAPOR), Amsterdam, The Netherlands, September.

1. The Emergence of Spiral of Silence from Individual Behaviors: Agent-based Modeling of The Spiral of Silence Theory Web Mining Lab Department of Media and Communication City University of HONG KONG 9/28/2011 2:27:36 PM Chengjun WANG 1 WAPOR2011

2. Introduction The formation and change of public opinion. Spiral of silence theory (SOS) explains the opinion dynamics in the aspects of individuals’ interactions with mass media and reference groups. Debates on the fundamental requisites of SOS. The inconsistent findings of empirical studies. Lack of analyzing the interplay between aggregate-level variables and individual-level predictors. 9/28/2011 2:27:37 PM 2 WAPOR2011 This is an exploratory study in order to analytically answer the followings two general questions: First, what’re the boundary conditions of SOS? Second, how does SOS come out, and evolve along time?

3. Theoretical Framework:Dual climate of opinion Why people jumped on the bandwagon of the expected winner at the last minute? Noelle-Neumann (Elisabeth Noelle-Neumann, 1984, 1993) proposed the assumption of dual climate of opinion: the climate people observe directly from the reference groups and the climate portrayed by the media. 9/28/2011 2:27:37 PM WAPOR2011 3

4. Specific Research Questions For those who hold the opinion of the mass media, the reference groups will reinforce the influence of the mass media. On the contrary, for the people holding the opinion of against that of the mass media will turn to the reference groups to find more supports. RQ1: What’s the boundary condition of a stable existence of spiral of silence? We would assert that spiral of silence is size-dependent: The scale of social interaction both on the local scope and on the society level are constrained by the size of population, and the size of reference groups. RQ2-1: How does the population size influence the emergence of spiral of silence? RQ2-2: How does the size of reference groups influence the emergence of spiral of silence? Viewing the phenomenon as a process with the time dimension is very important (Allport, 1937). RQ3: How does the number of people falling silent change over time? 9/28/2011 2:27:37 PM WAPOR2011 4

5. Method & Measure Agent-based modeling (ABM) is formally defined as a computational method that enables the modelers to create, analyze, and experiment with models composed of agents that interact within an environment (Gilbert, 2008) . The willingness to express continuous variable deprived from a uniform normal distribution. The mean of the normal distribution is 0, and the standard deviation of the distribution is 1. The climate of the reference groups Each agent has a radius of observation, and it can only monitor the climate of its reference group in the local scope. The sum of the willingness to express of reference groups in each agent’s radius of vision, is the opinion climate of the reference groups. The climate of the mass media The mass media is one kind of environment the agents living in. The influence of media randomly taking from (0, 1, 2, 3, 4, 5) 9/28/2011 2:27:37 PM WAPOR2011 5

6. Boundary Conditions of SOS:RQ1: What’s the boundary condition of a stable existence of spiral of silence? Chaos: Strong Reference Group Given the boundary condition of strong reference groups (compared with the influence of mass media), there is no guarantee for the stable existence of spiral of silence. 9/28/2011 2:27:37 PM 6 WAPOR2011

7. Global Regularity of SOS:Strong Mass Media (α/β=1, 10; radius=3; N=1000) 9/28/2011 2:27:37 PM WAPOR2011 7

8. Size-dependent SOSRQ2-1: How does the population size influence the emergence of spiral of silence? 9/28/2011 2:27:37 PM WAPOR2011 8

9. Size-dependent SOS RQ2-2: How does the size of reference groups influence the emergence of spiral of silence? 9/28/2011 2:27:37 PM WAPOR2011 9

10. Falling silent togetherRQ3: How does the number of people falling silent change over time? 9/28/2011 2:27:37 PM WAPOR2011 10

11. Discussion and Conclusion Limitations Contributions Discussions: Kelly (1952) emphasize two functions of reference group. Conclusions: the findings suggest: first, stable existence of spiral of silence is contingent upon the comparative strength of mass media over reference groups; second, heterogeneous individuals‟ bottom-up interactions with mass media and reference groups at the local scope give rise to the spiral of silence as an emergence of macroscopic regularity, to be specific, the growth rate of spiral of silence decreases over time, the number of the people falling silent per time is in accordance with Pareto distribution. 9/28/2011 2:27:37 PM WAPOR2011 11

12. end .Thank YOU FOR YOUR ATTENTION! 9/28/2011 2:27:37 PM Welcome to contact us! http://weblab.com.cityu.edu.hk 12 WAPOR2011

13. Appendix 1Convergence of close agents 9/28/2011 2:27:37 PM WAPOR2011 13

14. Appendix 2Model Fit 9/28/2011 2:27:37 PM WAPOR2011 14

15. Appendix 3ABM Agent-based modeling (ABM) is formally defined as a computational method that enables the modelers to create, analyze, and experiment with models composed of agents that interact within an environment (Gilbert, 2008) . It is designed to explore the minimal conditions or assumptions required by specific social phenomenon which emerges at a higher level of organization (Macy & Willer, 2002 It allows us to identify specific mechanisms which can help outline the micro-macro links (Squazzoni, 2008). Individuals make reactions to the environment over time, and the system evolve to emerge global changes. 9/28/2011 2:27:37 PM WAPOR2011 15

16. Appendix 4Model Specification 9/28/2011 2:27:37 PM WAPOR2011 16