Generating a Specific Class of Metaphors

1 I n t r o d u c t i o n Although some progress has been made in the area of metaphor understanding, little has been made in metaphor generation. Current solutions rely upon a rather direct encoding of alternatives. There is no computational theory that can account for metaphor generation from basic principles. Although generating all types of metaphors from basic principles is very difficult, there is a subset of metaphors that are prevalent in natural expressions and perhaps more amenable to computational approaches. We call these transparentlymotivated (T-M) metaphors (Jones and McCoy 1992). Interestingly, metaphors in general, as well as the class described here, can be used to achieve important textual goals (e.g., brevity, conceptual fit, focus, perspective). Metaphorical expressions often reflect conceptual models which are the basis for how we understand the world. Mark Johnson (1987) has made some important observations about the building blocks of thought, most notably that they are tied closely to our bodily experience. Among the building blocks he has described are attraction, blockage and containment. Consider describing the purchase of shares of stock as, "I took $2500 out of my money market account and put it into Exxon common stock." The speaker did not literally put money into the stock, but rather bought stock with the money. This metaphor is based on the simplifying concepts that represent investments as containers which can hold money. When we write and talk we automatically use non-literal expressions that reflect our common conceptual groundings. These lead to very natural and easily understood expressions because we (speaker and audience) share these common conceptual groundings.