Cross-mapped Analogies : Pitting Systematicity against Spurious Similarity

An analogy can be viewed as a device for conveying that two domains share significant relational structure even though they may not share surface similarity . The value of an analogy lies in its ability to give a causal or explanatory coherence to a new domain through the transference of a mutually-constraining set of relations . In Gentner's (1980, 1982, 1983) structure-mapping theory, this is called the systematicity principle . Intuitively . systematicity reflects people's tacit preference for coherence and deductive power in analogy . Syntactically, systematicity is realized as a preference for mapping relations that are governed by higher-order constraining relations that can themselves be mapped . The use of systematzcity appears to be a central aspect of adult competence in comprehending analogies . In this research ,we investigate two questions concerning the nature of this competence: (1) the role of systematicity in the on-line mapping process and (2) the developmental course of the use of systematic knowledge in analogical mapping . . The first questzon is exactly how pystematicity enters into the mapping process . Is it/simply a passive desideratum which conveys the complexity, utility, or aptness of an analogy once it has been correctly interpreted ? In accordance with structure-mapping theory, we suggest that systematicity plays a decisive role in the mapping process itself . More specifically, our aim is to show that the presence of systematic structure in the base domain can help people keep the mapping process on track . Moreover . this affect should be most pronounced for difficult mappings . That is . the less transparent the object correspondences are between base and target, the more important will be the abilitv to take advantage of systematic structure . Without systematicity . spurious similarities between domains are likely to mislead in the mapping process . To illustrate these principles, we offer a brief analysis of Rutherford"s analogy between the solar system and the hydrogen atom . Consider the case where a person hears the Rutherford analogy for the first time. According to structure-mappinA theory, the transference of knowledge from the base domain (e .g . the solar system) to the target domain (e .g ., the hydrogen atom) involves a mapping process in , which the objects from the base are placed in correspondence with objects in the target, e .g . . sun --> nucleus, planet --> electron . Then predicates are mapped from the base to the target according' to the following three mapping rules : (1) The relations between objects in the base tend to be mapped across . For example, the lower-order relations ;