Abstract

This paper responds to the claim of Veale, O’Donoghue and Keane (1995) that SME (Falkenhainer, Forbus & Gentner, 1989; Forbus, Ferguson & Gentner, 1994) performs poorly on noun-noun comparisons, such as A surgeon is like a butcher. Veale et al. argue that such noun-noun comparisons involve “object-centered representations” that do not contain higher-order relations, and that Sapper’s chaining of expressions that share entity arguments provides a better model than SME for such comparisons. They also literally claim that SME will require longer than the lifetime of the universe to align Sapper’s noun representations. We refute both their cognitive and computational claims here, focusing on (1) the psychology of noun-noun metaphors; (2) how Sapper works; and (3) SME’s actual performance. The psychology of noun-noun metaphors Veale et al.’s claim that noun-noun metaphors require object-centered representations is inconsistent with psychological findings. People readily interpret noun-noun metaphors in terms of common relational structure; for example, “Cigarettes are like time bombs.” is interpreted to mean that both cause damage after a quiescent period. Gentner and Clement (1988) found that adult ratings of metaphor aptness are positively correlated with the amount of relational information in their interpretations (as independently judged) and are noncorrelated or negatively correlated with the amount of object-attribute information. Like humans, SME can produce both relational and attributional matches, but generally prefers the former.