Shen and Balaban: "Metaphorical (In)Coherence in Discourse" (1999)

One consequence of the strong "conceptual structure" view of metaphors is that metaphorical expressions are always understood through activations of an underlying metaphor or source domain.

As a consequence, one would expect that writers and speakers were primed to use several instantiations of the same metaphor once they has used a single instantiation of it: We have come a long way since our humble beginnings, we were stuck, but now we're back on track, etc., etc.

But this doesn't seem to be the case, Yeshayahu Shen and Noga Balaban show in this paper. Their methodology pivots around a comparison of a corpus of "planned" or highly explicit uses of a metaphor, and corpus of spontaneous uses. Using a number of different measures, they find that the "planned" newspaper clippings in their corpus exhibit much, much higher metaphorical coherence than the unplanned.

They conclude:

None of the analyses [in the paper] supports the claim that, as a default, unplanned discourse exhibits a coherent distribution of metaphorical expressions. […] The use of metaphors in unplanned discourse appears more like free, uncontrolled "navigation" between a large number of root metaphors than a consistent elaboration of any unifying root metaphors. Indeed, special planning seems to be required to make discourse metaphorically coherent. (p. 151)

As a consequence, it would seem that kliché metaphors have a different cognitive status than deliberate, explicit, and overt metaphors do. Conventional metaphors do not necessarily activate any interesting cognitive architecture:

Rather, the fact that conventional metaphorical instantiations of a given metaphor appear in a given discourse does not necessarily seem to reflect a corresponding activation (in the producer's mind) of the root metaphor. Perhaps this means that the use of conventional expressions in real discourse is autonomous in that, under such conditions of natural discourse production, they do not rely on the functional activation of the entire root metaphor and, in that sense, their meanings are divorced from the underlying conceptual metaphors posited by the CM theory. (p. 152)

Thus, no role for "conceptual structures" with respect to conventional metaphors.

Shen and Balaban also note in passing that "metaphorical shifts in the unplanned passages occurred not only at the intersentential level but also at the intrasentential level" (p. 148). They found, for instance, inconsistent metaphors packed closely together in phrases like "cook up a trap" (p. 150) or the following examples (p. 148):

The peace process is moving forward and ripening (FOREIGN POLICY IS A JOURNEY/FRUIT).

The first step [of the Oslo agreement], the real embryonic one, actually works well (FOREIGN POLICY IS A JOURNEY/A PERSON/A MACHINE).

Violence is eating away the foundations of democracy (THE POLITICAL SYSTEM IS A FOOD/A BUILDING).

Given the reading speed of an ordinary adult, it seems reasonable to assume that these metaphor pairs cannot possibly be comprehended through a process involving mental imagery.