Why No Mere Mortal Has Ever Flown Out to Center Field

The English past tense system has recently been used to argue that formal grammatical categories (such as root. rule, and lexical item) may not be necessary to explain the acquisition and knowledge of language. Rumelhart and McClelland (1986) devised a connectionist model relying solely on phonological information; it is often suggested that any deficiencies of such a model can be remedied by supplying it with semantic information. These proposals are incorrect: Grammatical categories and abstract morphological structure are indispensable and cannot be replaced with semantics while preserving the patterns of psychological generalization in the system. Linguists have noted that irregular past tense mappings (e.g., fly/flew; stick/stuck) apply only when a verb’s root is marked in the lexicon as having an irregular past. Because nouns are never so marked, verbs with noun roots-denominal verbs-are regular even if they are phonologically identical to irregular verbs, hence: flied out/‘flew auf to center field; h/gh-sficked/*highstuck the goalie. Experiment 1 shows that adult subjects are highly sensitive to this principle when rating regular and irregular past tense forms of navel versions of irregular sounding verbs: New verbs formed from nouns were judged as better with a regular past tense (e.g., line-drived was the preferred past of “to hit a line drive”); new verbs formed from verbs were judged as better with an irregular post tense (e.g.. line-drove was the preferred past of “to drive along a line”).