  Bounded confidence models of opinion dynamics have been actively studied in
recent years, in particular, opinion formation and extremism propagation along
with other aspects of social dynamics. In this work, after an analysis of
limitations of the Deffuant-Weisbuch (DW) bounded confidence, relative
agreement model, we propose the Mixed model that takes into account two
psychological types of individuals. Concord agents (C-agents) are friendly
people; they interact in a way that their opinions get closer always. Agents of
the other psychological type show partial antagonism in their interaction
(PA-agents). Opinion dynamics in heterogeneous social groups, consisting of
agents of the two types, was studied on different social networks. Limit cases
of the mixed model, pure C- and PA-societies, were also studied. We found that
group opinion formation is, qualitatively, almost independent of the topology
of networks used in this work. Opinion fragmentation, polarization and
consensus are observed in the mixed model at different proportions of PA- and
C-agents, depending on the value of initial opinion tolerance of agents. As for
the opinion formation and arising of "dissidents", the opinion dynamics of the
C-agents society was found to be similar to that of the DW model, except for
the rate of opinion convergence. Nevertheless, mixed societies showed dynamics
and bifurcation patterns notably different to those of the DW model. The
influence of biased initial conditions over opinion formation in heterogeneous
social groups was also studied versus the initial value of opinion uncertainty,
varying the proportion of the PA- to C-agents. Bifurcation diagrams showed
impressive evolution of collective opinion, in particular, radical change of
left to right consensus or vice versa at an opinion uncertainty value equal to
0.7 in the model with the PA/C mixture of population near 50/50.
