COHESION, CONSENSUS AND EXTREME INFORMATION IN OPINION DYNAMICS

Opinion formation is an important element of social dynamics. It has been widely studied in the last years with tools from physics, mathematics and computer science. Here, a continuous model of opinion dynamics for multiple possible choices is analysed. Its main features are the inclusion of disagreement and possibility of modulating external information/media effects, both from one and multiple sources. The interest is in identifying the effect of the initial cohesion of the population, the interplay between cohesion and media extremism, and the effect of using multiple external sources of information that can influence the system. Final consensus, especially with the external message, depends highly on these factors, as numerical simulations show. When no external input is present, consensus or segregation is determined by the initial cohesion of the population. Interestingly, when only one external source of information is present, consensus can be obtained, in general, only when this is extremely neutral, i.e., there is not a single opinion strongly promoted, or in the special case of a large initial cohesion and low exposure to the external message. On the contrary, when multiple external sources are allowed, consensus can emerge with one of them even when this is not extremely neutral, i.e., it carries a strong message, for a large range of initial conditions

Agent-Based Modeling of Consensus Group Formation with Complex Webs of Beliefs

Formation of consensus groups with shared opinions or views is a common feature of human social life and also a well-known phenomenon in cases when views are complex, as in the case of the formation of scholarly disciplines. In such cases, shared views are not simple sets of opinions but rather complex webs of beliefs (WoBs). Here, we approach such consensus group formation through the agent-based model (ABM). Agents’ views are described as complex, extensive web-like structures resembling semantic networks, i.e., webs of beliefs. In the ABM introduced here, the agents’ interactions and participation in sharing their views are dependent on the similarity of the agents’ webs of beliefs; the greater the similarity, the more likely the interaction and sharing of elements of WoBs. In interactions, the WoBs are altered when agents seek consensus and consensus groups are formed. The consensus group formation depends on the agents’ sensitivity to the similarity of their WoBs. If their sensitivity is low, only one large and diffuse group is formed, while with high sensitivity, many separated and segregated consensus groups emerge. To conclude, we discuss how such results resemble the formation of disciplinary, scholarly consensus groups

잠재 심리학 변수 및 사회적 상호작용을 고려한 새로운 일반화된 이질적 데이터 모형

학위논문 (박사) -- 서울대학교 대학원 : 공과대학 협동과정 기술경영·경제·정책전공, 2020. 8. 이종수.사회적 상호작용은 개인의 태도 및 의견, 개인의 선호, 그리고 개인의 행동에 중요한 영향을 미친다. 따라서 사회적 상호작용은 사회과학 분야에 매우 중요한 연구 대상이다. 사회적 상호작용은 크게 구전 효과와 관찰된 학습 두가지로 나눌 수 있다. 기존 경제학 분야의 선택 모형에서는 주로 관찰된 학습을 사회적 상호작용으로 간주하였다. 구전 효과는 태도나 행위의 경향성 분석에 많이 연구되어 왔지만 선택 모형에 고려하는 것은 어려움이 많았다. 그리고, 많은 선택모형에서 개인의 의사결정 과정을 더 잘 이해하고 모형의 예측력을 향상시키기 위해 개인의 잠재적 심리학 변수를 추가하고자 하였다. 사회적 상호작용이 개인의 심리학적 특성에 많은 영향을 미친다는 것은 이미 많은 연구를 통해서 입증되어 왔다. 하지만 사회적 상호작용이 개인의 잠재적 심리학 변수에 미치는 영향을 다룬 연구는 매우 드물었다. 또한, 개인의 행동 사이에 존재한 상관관계를 선택모형에 동시에 다루지 못하면 편향된 추정결과를 얻을 수 있다. 혼합형 종속변수를 동시에 추정하는 모형은 꾸준히 개발되어 왔지만 여기에 사회적 상호작용을 고려한 연구는 찾아보기 힘들다. 본 연구에서는 두가지 사회적 상호작용을 모두고려하는 다중 선택 모형을 제안하였다. 제안한 선택 모형은 사회적 상호작용을 고려할 수 있을 뿐만 아니라 내생적 다중 선택을 다룰 수 있으며 혼합적 종속변수까지 포함할 수 있다. 본 연구에서 먼저 시뮬레이션 분석을 통해서 모델의 유용성을 입증한 다음에 실증분석으로 기존 모델에서 확인할 수 없었던 사회적 상호작용이 개인의 행위에 미치는 영향을 분석하였다. 사회적 상호작용을 고려하지 않으면 추정된 결과가 편향될 수 있으며 변수의 계수를 과대 추정할 가능성이 있다는 것을 실증연구를 통해서 증명했다.Social interaction has enormous effect on individuals attitude and opinion, preferences, and behaviors. Social interaction is one of the most important study regions within social sciences. There are generally two types of social interaction: word-of-mouth and observed learning. Observed learning is considered as social interaction is majority of choice models in economic studies. However, word-of-mouth is largely studied in attitude and behavior propensity related studies and hardly ever been incorporated in choice models due to the characteristics of the word-of-mouth. On the other hand, choice models have tried to incorporate individuals psychological variables in order to get better understanding of individual decision process and to improve the forecasting ability of the models. However, there are limited studies have considered the effect of social interaction on the individuals psychological variables which is one of the major mechanisms of social interaction. Moreover, since individuals behaviors endogenously correlated themselves, consideration of endogenously correlated outcomes simultaneously is necessary for many choice situations. Though there are some studies derived handful model for multiple choices, only a few models have incorporated the social interaction into the model. This study proposes a new multiple endogenous choice model incorporating both types of social interaction. Furthermore, the proposed model is capable of dealing with multiple endogenous heterogenous dependent variables. The dissertation conducts a simulation study to confirm the performance of proposed model and an empirical study to provide evidence of how social interaction effect on individuals choice and proof that ignoring the effect of social interactions may leads to inconsistent estimation and may over-estimated the variable effects.Chapter 1. Introduction 1 1.1 Research Background 1 1.2 Research Object 4 1.3 Research Outline 8 Chapter 2. Literature Review 10 2.1 Theoretical Insights 10 2.1.1 Studies on Human Behavior 11 2.1.2 Studies on Word-of-Mouth 14 2.2 Choice Models 20 2.2.1 Choice Models with Psychological Factors 20 2.2.2 Choice Models with Spatial/Social Dependence 32 2.2.3 Models of Mixed Data 41 2.3 Limitations of Previous Research and Research Motivation 46 Chapter 3. Model Specification 48 3.1 Latent Psychological Variable Structural Equation Model 49 3.2 Latent Variable Measurement Equation Model 50 3.2.1 Single Dependent Variable 50 3.2.2 Multiple Dependent Variables 52 3.3 Estimation Methodology 60 3.4 Simulation Study 62 3.4.1 Simulation Design 62 3.4.2 Simulation Results 65 Chapter 4. Empirical Study 73 4.1 Empirical Study Background and Specification 73 4.1.1 Latent Psychological Variables 75 4.1.2 Endogenous Outcomes 78 4.2 Data Description 80 4.3 Estimation Results 87 4.3.1 Structural Equation Model for Latent Psychological Variables 87 4.3.2 Effect of Latent Psychological Variables on Endogenous Outcomes 90 4.3.3 Comparison of the GHDM models 96 Chapter 5. Conclusion 100 5.1 Concluding Remarks and Contribution 100 5.2 Limitations and Future Studies 103Docto

COHESION, CONSENSUS AND EXTREME INFORMATION IN OPINION DYNAMICS

Opinion formation is an important element of social dynamics. It has been widely studied in the last years with tools from physics, mathematics and computer science. Here, a continuous model of opinion dynamics for multiple possible choices is analysed. Its main features are the inclusion of disagreement and possibility of modulating external information/media effects, both from one and multiple sources. The interest is in identifying the effect of the initial cohesion of the population, the interplay between cohesion and media extremism, and the effect of using multiple external sources of information that can influence the system. Final consensus, especially with the external message, depends highly on these factors, as numerical simulations show. When no external input is present, consensus or segregation is determined by the initial cohesion of the population. Interestingly, when only one external source of information is present, consensus can be obtained, in general, only when this is extremely neutral, i.e., there is not a single opinion strongly promoted, or in the special case of a large initial cohesion and low exposure to the external message. On the contrary, when multiple external sources are allowed, consensus can emerge with one of them even when this is not extremely neutral, i.e., it carries a strong message, for a large range of initial conditions