Keysar, Shen, Glucksberg, Horton: "Conventional Language: How Metaphorical Is It?" (2000)

This article reports an set of experiments on conventionalized metaphors. The experiments support the claim that stock metaphors such as He defended his argument are not in any real psychological sense understood by means of (literal) defense.

The experiments rest on the assumption that if the literal meanings of such metaphors are in fact "accessed" or "activated" during the reading of the metaphor, then they will be more readily available immediately after the reading (as in the priming effect known from other contexts). This availability is estimated by measuring the reading time of a sentence that uses the same source domain (e.g., defense) in a non-trivial way.

For instance, consider these three primings and stimuli:

1. prolific researcher, conceiving ideas ===> weaning her latest child
   
2. fertile researcher, giving birth to ideas ===> weaning her latest child

In the first case, the stimulus consists of stock phrases, in the second it consists of more original metaphors (but using the same mapping). If both types of metaphor are actually unpacked by thinking about what children and giving birth means, then they should prime subjects equally much for the metaphor that follows.

This, however, is not the case---at least not if reading time is used to measure the priming effect. Reading the target stimulus (weaning her latest child) is significantly slower when subjects are primed as in the first example compared to when they are primed as in the second.

This, in essence, is the result reported in the article. As the authors say:

Thus, while his criticism was right on target might not require use of a mapping between argument and war, his criticism was a guided cruise missile might very well do so. (p. 580)

By the way, the article appeared Journal of Memory and Language 43 (2000).