On learning the past-tenses of English verbs: implicit rules or parallel distributed processing

Abstract : This paper presents an alternative to the standard rule based account of a child's acquisition of the past tense in English. Children are typically said to pass through a three-phase acquisition process in which they first learn past tense by rote, then learn the past tense rule and over regularize, and then finally learn the exceptions to the rule. We show that the acquisition data can be accounted for in more detail by dispensing with the assumption that the child learns rules and substituting in its place a simple homogeneous learning procedure. We show how rule-like behavior can emerge from the interactions among a network of units encoding the root form to past tense mapping. A large computer simulation of the learning process demonstrates the operating principles of our alternative account, shows how details of the acquisition process not captured by the rule account emerge, and makes predictions about other details of the acquisition process not yet observed. Keywords: Learning; networks; Language; Verbs; Perceptions; Morphology.