Previous work indicates that action-control processes influence perceptual processes: The identification probability of a left-or right-pointing arrow is reduced when it appears during the execution of a compatible left-right-key press (Mtisseler& Hommel,in press). The present study addresses the question of whether this effect would also be observed in a detection task-that is, with judgments that do not require discriminating between left-and right-pointing arrows. Indeed, we found comparable effects in both the identificationtask and the detection task. This outcome is interpreted within a cornrnoncodingframework, which holds that stimulus processing and action control operate on the same codes.The present article deals with the relationship between perception and action and, in particular, with the effects of compatibility or incompatibility between stimuli and responses. Yet, in contrast to the numerous investigations on the impact of stimulus information on response selection (for overviews, see Hommel &Prinz, 1997, andProctor &Reeve, 1990), our concern is with the reverse direction-that is, with the impact of action on perception, We found empirical evidence for such an impact in a recent study where subjects were presented with a masked left-or right-pointing arrow while executing a prepared left-or right-key press (Musseler & Hommel, in press). Surprisingly, when asked to identify the arrow at leisure afterwards, subjects were consistently better with incompatible relationships between response and arrow (e.g., left response, right-pointing arrow) than with compatible relationships (e.g., left response, left-pointing arrow), Our interpretation ofthis finding rests on the assumption that stimulus processing and action control operate on the same kind of-and sometimes even identicalcodes (cf. the common-coding approach outlined by Prinz, 1992). According to this approach, a left response, for example, would be represented and controlled by the same cognitive LEFT code that is used in coding a left-pointing arrow (Musseler & Prinz, 1996). However, there is reason to assume that executing an action results in a selfinhibition of the action-related codes-hence, a refractory phase (MacKay, 1986). If so, executing a left response should be associated with a temporarily decreased sensitivity to LEFT stimuli, such as left-pointing arrows. The