RULES OR ASSOCIATIONS IN THE ACQUISITION OF MORPHOLOGY - THE FREQUENCY BY REGULARITY INTERACTION IN HUMAN AND PDP LEARNING OF MORPHOSYNTAX

When fluent English speakers are asked to produce past tense forms, th eir latencies are affected by frequency of past tense forms when gener ating irregular inflections, but not when generating regular ones. Thi s interaction has been used to support hybrid accounts of morphosyntax where regular inflections are computed by an affixation rule in a neu rally based symbol manipulating syntactic system, while irregular verb s are retrieved from an associative memory. This article describes adu lt learning of morphosyntax in a novel language where frequency and re gularity are factorially combined. The accuracy and latency data demon strate frequency effects for both regular and irregular forms early in the acquisition process. However, as learning progresses, the frequen cy effect on regular items diminishes whereas it remains for irregular items. The regularity by frequency interaction is a natural consequen ce of the power law of practice and is thus entirely consistent with a ssociative learning processes: Regularity is frequency by another name . Performance of a simple connectionist system, when trained on the sa me materials, shows a very close correspondence to the human acquisiti on data.