Dual-Coding Theory and Connectionist Lexical Selection

DUAL-CODING THEORY AND CONNECTIONIST LEXICAL SELECTION Ye-Yi Wang* Computational Linguistics Program Carnegie Mellon University Pittsburgh, PA 15232 Internet: yyw@cs.cmu.edu Abstract We introduce the bilingual dual-coding theory as a model for bilingual mental representation. Based on this model, lexical selection neural networks are imple- mented for a connectionist transfer project in machine translation. Introduction Psycholinguistic knowledge would be greatly helpful, as we believe, in constructing an artificial language processing system. As for machine translation, we should take advantage of our understandings of (1) how the languages are represented in human mind; (2) how the representation is mapped from one language to another; (3) how the representation and mapping are acquired by human. The bilingual dual-coding theory (Paivio, 1986) partially answers the above questions. It depicts the verbal representations for two different languages as two separate but connected logogen systems, charac- terizes the translation process as the activation along the connections between the logogen systems, and at- tributes the acquisition of the representation to some unspecified statistical processes. We have explored an information theoretical neu- ral network (Gorin and Levinson, 1989) that can ac- quire the verbal associations in the dual-coding theory. It provides a learnable lexical selection sub-system for a conneetionist transfer project in machine translation. Dual-Coding Theory There is a well-known debate in psycholinguistics concerning the bilingual mental representation: inde- pendence position assumes that bilingual memory is represented by two functionally independent storage and retrieval systems, whereas interdependence po- sition hypothesizes that all information of languages exists in a common memory store. Studies on cross- language transfer and cross-language priming have *This work was partly supported by ARPA and ATR In- terpreting Telephony Research Laboratorie. provided evidence for both hypotheses (de Groot and Nas, 1991; Lambert, 1958). Dual-coding theory explains the coexistence of in- dependent and interdependent phenomena with sepa- rate but connected structures. The general dual-coding theory hypothesizes that human represents language with dual systems -- the verbal system and the im- agery system. The elements of the verbal system are logogens for words in a language. The elements of the imagery system, called "imagens", are connected to the logogens in the verbal systems via referential connections. Logogens in a verbal system are also in- terconnected with associative connections. The bilin- gual dual-coding theory proposes an architecture in which a common imagery system is connected to two verbal systems, and the two verbal systems are inter- connected to each other via associative connections [Figure 1]. Unlike the within-language associations, which are rich and diverse, these between-language associations involve primarily translation equivalent terms that are experienced together frequently. The interconnections among the three systems explain the interdependent functional behavior. On the other hand, the different characteristics of within-language and between-language associations account for the inde- pendent functional behavior. Based on the above structural assumption, dual-" coding theory proposes a parallel set of processing assumptions. Activation of connections between ref- erentially related imagens and logogens is called ref- erential processing. Naming objects and imaging to words are prototypical examples. Activation of …

Content truncated to 500 words