EVALUATING BEHAVIORAL AND NEUROIMAGING DATA ON PAST TENSE PROCESSING

Jaeger, Lockwood, Kemmerer, Van Valin, Murphy, and Khalak 1996 (Langua ge 72.3) reported an experimental study that provided reaction time an d PET neuroimaging data said to support Pinker's (1991) theory of infl ectional morphology in which rule-governed forms and exceptions are pr ocessed by separate mechanisms. The results were also taken as evidenc e against connec tionist accounts in which a single processing system generates both types of forms. We provide a critical analysis of the s tudy that yields three main conclusions: First, Jaeger ct al.'s data d o not provide strong evidence that rule-governed forms and exceptions are processed in separate brain regions. Second, there are problems wi th the design of dhe study that contaminate critical comparisons betwe en conditions. The results therefore afford alternative interpretation s related to experiment-specific factors rather than the regular-irreg ular distinction. Third, the dissociations between rule-governed forms and exceptions observed in studies such as Jaeger er al.'s can be acc ommodated by the connectionist theory. We conclude by offering suggest ions for future re search that would overcome the major limitations of this study and provide more decisive evidence bearing on the issues.