Cognitive control during selection and repair in word production.

Production of an intended word entails selection processes, in which first the lexical item and then its segments are selected among competitors, as well as processes that covertly or overtly repair dispreferred words. In two experiments, we studied the locus of the control processes involved in selection (selection control) and intercepting errors (post-monitoring control). Selection control was studied by manipulating the overlap (contextual similarity) in either semantics or in segments between two objects that participants repeatedly named. Post-monitoring control was examined by asking participants to reverse, within each block, the name of the two objects that were either semantically- or segmentally-related, thus suppressing a potent, but incorrect, response in favor of an alternative (reversal). Results showed robust costs of both contextual similarity (which increased with the degree of similarity between target and context) and reversal, but the two did not interact with one another. Analysis of individual differences revealed no reliable correlation between the cost of contextual similarity when pairs were semantically- or segmentally-related, suggesting stage-specific selection control processes. On the other hand, the cost of reversal was reliably correlated between semantically- and segmentally-related pairs, implying a different control process that is shared by both stages of production. Collectively, these results support a model in which selection control operates separately at lexical and segmental selection stages, but post-monitoring control operates on the segmentally-encoded outcome.