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sufficient evidence to suggest that conversation is generally
successful. It appears to be largely a matter of doctrine whether
communicators are assumed to generally understand each other
and signify the same ideas with the same language—this is
known as the doctrine of intersubjective conformity.^2 The
skeptical position that neither interlocutors (the participants in
dialogues) nor external observers can ever completely verify
whether the interlocutors have really understood each other is so
robust that this skeptical position cannot be refuted. However, a
weaker notion of intersubjective conformity is available. The
weaker notion is that dialogue participants or observers may
pragmatically behave as if there has been mutual understanding
unless contrary evidence emerges. Nonetheless, in some
contexts, forensic ones in particular, it seems safer to adopt the
null hypothesis about communicative success which holds that
communication attempts have been unsuccessful unless positive
evidence exists that mutual understanding has emerged
sufficiently to make one reject the null hypothesis and accept the
alternative hypothesis that communication has been successful,
rather than to assume success by default.
This article focuses on the development and testing of
objective measures for assessing the likelihood of shared
understanding of linguistic communication in contexts where
shared understanding has a critical role, such as in forensic
interrogations or other courtroom interactions. After motivating
a principle of skepticism in assessing the likelihood of mutual
understanding emerging for all participants in any given
dialogue, a method is described which is deployed here to
quantify levels of engaged interaction as a proxy measure for
mutual understanding. The basic idea is that where positive
evidence is needed to assert that dialogue participants have
understood each other, levels of interaction that are statistically
significant in divergence from random interactions provide a
tangible basis for asserting that corresponding levels of mutual
understanding may have been achieved. The method is
illustrated with respect to an excerpt of a dialogue transcript
(^2) TALBOT J. TAYLOR, MUTUAL MISUNDERSTANDING: SCEPTICISM AND
THE THEORIZING OF LANGUAGE AND INTERPRETATION 29 (1992).