Are speech error patterns affected by a monitoring bias?

Abstract

This paper reviews the proposal that observed patterns of speech errors are partly a function of language production mechanisms (that create an underlying pattern of errors), and partly a function of self-monitoring mechanisms (that intercept some errors more often than others and thus alter the underlying pattern). It is essential to find out whether such a ‘monitoring bias’ is real, because of the important role it plays in debates about the interactivity or modularity of the language production system. Data are reviewed that support an important precondition of monitoring bias accounts: The monitor is fast enough to intercept errors in the speech plan. Subsequently, a number of criteria are proposed for allowing a monitoring bias explanation, and five speech error patterns are compared with those criteria. I conclude that in no case is there unequivocal evidence for a monitoring bias, but that such an account is very plausible in the case of some speech error patterns (e.g., the lexical bias effect), but very implausible in the case of other patterns (e.g., morphophonological effects on errors of subject-verb number agreement).