Intervention of DeGroot model based opinion dynamics by soft control

Opinion dynamics has become an important subject to study the evolution of public opinion, as well as their impact on public policy making. Most research of opinion dynamics focus on how to reach consensus or why disagreement is induced. In this paper, we consider the important problem of public opinion intervention and make the following major contributions. First, we present a modified DeGroot model by adding a shill (shills) to the original system to lead the opinion of all individuals to our expected direction while not altering the mechanism of the original system. Second, the impact of the shill on the evolution of the group opinion are analyzed theoretically and its influence is quantitatively presented. Third, the impacts of different intervention strategies are discussed in different situations. At last, it’s demonstrated in our numerical tests that we can lead the group opinion to our expected direction by adding a shill (shills) without any intervention purpose.