  An important side effect of the evolution of the human brain is an increased
capacity to form opinions in a very large domain of issues, which become points
of aggressive interpersonal disputes. Remarkably, such disputes are often no
less vigorous on small differences of opinion than large differences. Opinion
differences that may be measured on the real number line may not directly
correspond to the subjective importance of an issue and extent of resistance to
opinion change. This is a hard problem for field of opinion dynamics, a field
that has become increasingly prominent as it has attracted more contributions
to it from investigators in the natural and engineering sciences. The paper
contributes a scale-free approach to assessing the extents to which
individuals, with unknown heterogeneous resistances to influence, have been
influenced by the opinions of others.
