I have heard that there is an election today, and I've heard that it's going to be close and contentious, but I don't care. Here at Mixing Memory, we're only worried about metaphor for now (and soon, classical vs. connectionist architectures, and perhaps after that, idioms, and after that... the sky's the limit). In the first two metaphor posts, I talked about the history of cognitive theories of metaphor, and the structure mapping theory of metaphor. Now it's on to the other prominent view of metaphor, one that differs almost entirely in its description of what metaphors are. Throughout most of the history of western philosophy, and certainly throughout the history of cognitive science, metaphors have been viewed as comparisons. This was the view that Aristotle took, it's the view of C. S. Peirce (as far as I can tell, and thanks to Clark for the tip), and it is the view of Black, Ortony, the cognitive linguists (shudder), and the structure mapping theoriests. However, there have been criticisms of this account among some cognitive psychologists. Most notably, Glucksberg and his colleagues have claimed that the comparison view of metaphor does not fully capture the assymetry inherent in all metaphorical statements. Most comparisons are, in fact, asymetrical. The classic example of asymetry in comparisons comes from work by Amos Tversky. He showed that participants judged "North Korea is like Red China" to be better comparisons than "Red China is like North Korea," because the features that are relevant to the comparison (e.g., their status as communist states) are more salient in one domain (China) than in the other (Korea). Furthermore, Korea shares a higher portion of its features with China than China does with Korea. However, the assymetry of such comparisons is not absolute. One can say that China is like Korea, and get away with it. However, unlike ordinary comparisons, metaphors are not reversible. While "My lawyer is a shark" makes sense, "The shark is a lawyer" does not. This irreversability is not captured by comparison theories of metaphor, according to Glucksberg, and the failure to do so demands a new approach to metaphor. So now, instead of viewing metaphor as comparison, metaphor is treated as categorization. Taxonomic category relationships are irreversable. A robin is a bird, but birds are not robins. Thus, treating metaphors as categorization statements captures the extent of the asymmetry in metaphor.
The gist of the categorization theory of metaphor is fairly simple. Metaphors are is-a, or class-inclusion statements in which the topic is said to be a member of a category represented by the vehicle. The vehicle itself is not the category into which the topic is placed. Instead, the vehicle is chosen because it is a member of the category that exemplifies the category's defining features. In some cases, the category is an existing category, but in most cases, it will have to be produced on-line during the processing of the metaphor. For example, in the metaphor "My job is a jail," the vehicle, jail, is chosen because it is a salient member of a category created specifically for the metaphor. In this case, the category created specifically for the metaphor would be something like "confining places." Because the vehicle stands for both the concept to which it ordinarily refers, and the category into which the topic is being placed, the vehicle is said to have "dual reference." The topic, in turn, as a member of the category, inherets all of the attributes of that category.1
The most recent version of the categorization view of metaphor, the attributive categorization theory2, the vehicle and topic interact to select which properties of the vehicle will be used to select the category the vehicle represents, and into which the topic will be placed. Once again, then, the attributive categorization theory resembles Black's interactive theory of metaphor. This interactive aspect of the categorization process helps solve two problems with the earlier categorization theories. The first is the problem of how we know which of the vehicle's features references the category. In this case, the topic itself helps to select these features. The second problem is the fact that any given vehicle can be used to represent different categories in different metaphors. By allowing the topic to select which features of the vehicle are relevant, the vehicle is then free to represent different categories when it is paired with different topics.
It's interesting, in the end, that even when metaphor is treated as categorization, a comparison is still needed to select which features define the category into which the topic is placed. As in all of the previous theories of metaphor, the topic must be compared to the vehicle in order to determine the relevant features in the vehicle. The categorization aspect of the theory mainly serves the purpose of creating the irreversability of the metaphor. Otherwise, the categorization process would be superfluous, and if a comparison theory of metaphor could create the level of asymmetry required of a theory of metaphor, this would probably render categorization theories obsolete. Introspectively, there doesn't seem to be any sort of categorization going on when we process metaphors. While this is not, of course, a damning charge for any cognitive theory, because most of the work in most cognitive tasks is going on unconsciously, it does make the categorization view feel a little odd. For these reasons, the categorization theory has not been widely accepted by theorists who have held comparison views of metaphor all along. A local war has erupted between the structure mapping and attributive categorization camps, and there's a lot of empirical evidence out there. In the next post, I'll try to cover some of it.
1 Glucksberg, S ., & Keysar, B . (1990) . Understanding metaphorical comparisons : Beyond similarity. Psychological Review, 97, 3-18.
2 Glucksberg, S ., McGlone, M. S., & Manfredi, D . (1997) . Property attribution in metaphor comprehension . Journal of Memory and Language, 36, 50-67 .