Connectionist Rules of Language

A modular connectionist network is described that learns the German verb paradigm. The architecture of the network is in accordance with the rule{associative memory hypothesis proposed by Pinker (1991): it is composed of a connectionist short-term memory enabling it to process symbolic rules and an associative memory acting as a lexicon. The network successfully learns the German verb paradigm and generalizes to novel verbs in ways that correspond to empirical data. Lesioning the model gives further evidence for the rule{ associative memory hypothesis: When the lexicon is cut oo, the network strongly overgeneralizes the regular participle , indicating that regular forms are produced with the short-term memory but irregular forms rely on the lexicon. However, in contrast to the rule{association theory, the two paths are not strongly dissociated, but both the short-term memory and the lexicon work together in producing many participles. The success of the network model is seen as evidence that emergent linguistic rules need not be implemented as rules in the brain.