Nonlinear Dynamical Model of Small Group Decision
Making
We present a quantitative model of small group decision
making by foreign policy elites in which group member positions or opinions
with respect to a given policy issue evolve in response to the influence
of other group members, external events, and incoming information. The form
of the model is guided by social psychology theories on attitude change and
information processing and cognitively-based approaches to foreign policy
decision making. The model dynamics are implemented via a set of coupled
nonlinear differential equations for the state vector of member opinions.
The nonlinear nature of the model enables it to capture intuitively reasonable
group dynamics inaccessible to linear models such as the sudden emergence
of consensus or major schisms due to relatively small changes in member opinions
or group cohesion, and the dependence of the outcome upon the sequence of
external events impacting the decision-making process. We address the stability
of equilibrium solutions corresponding to consensus or disagreement with
respect to incoming information using stochastic differential equations,
and we show how the use of bifurcation theory facilitates analytical insight
into the group dynamics. Computational simulations of the model display a
range of phenomena central to foreign policy decision making in the small
group context, such as groupthink, factionalism, and group-induced polarization
shifts, as well as open and balanced deliberations. We show results indicating
the regimes in parameter space where one would expect a given mode of group
behavior to be predominant. Methods for empirical implementation of
the model are discussed in the context of a case study.
Michael Gabbay
Information Systems Laboratories, Inc.
company website: http://www.islinc.com/
mgabbay@islinc.com