Negative Priming Without Overt Prime Selection BRUCE MILLIKEN, McMaster University STEVE JOORDENS, University of Toronto at Scarborough Abstract The procedure typically used to demonstrate negative priming requires subjects to respond to one of two simultaneously presented stimuli across two consecutive displays. Negative priming is defined by slower responses to targets in the second display that appeared as distractors in the first display, than to targets in the second display that did not appear in the first display. It is widely assumed that negative priming occurs as a result of the selection that occurs in the first display. In the present article, we show that negative priming can be observed without requiring subjects to respond selectively to one of two items in the first display. We argue that this result is useful for two reasons. First, it points out a fundamental misunderstanding concerning the procedure required to measure negative priming, a misunderstanding that has shaped much of the theoretical work done in this area. Second, we suggest that the procedure introduced here is of considerable utility in evaluating theoretical accounts of negative priming. To demonstrate this utility we report the results of two studies that assess the code co - ordination account of negative priming (Lowe, 1985; Tipper & Cranston, 1985). The priming paradigm is an empirical tool commonly used to examine the state of an internal representation of a recently presented stimulus. In a typical priming study, subjects are asked to identify or categorize visually presented target stimuli as quickly and accurately as possible. On some trials the target stimulus is identical to or semantically related to a stimulus that was displayed previously. On other trials the target is unrelated to previous stimuli. The conventional result obtained in such studies is that less time is required to respond accurately to a target when it follows an identical prime (e.g., Scarborough, Cortese, & Scarborough, 1977; Scarborough, Gerard, & Cortese, 1979) or a semantically related prime (e.g., Meyer & Schvaneveldt, 1971; Meyer, Schvaneveldt, & Ruddy, 1975) than when it follows an unrelated prime. The cause of priming effects remains a matter of considerable debate (e.g., see Becker, Moscovitch, & Behrmann, 1995; Joordens & Besner, 1992; Masson, 1991; 1995; McKoon & Ratcliff, 1992; McNamara, 1992; 1994; Neely, 1991; Ratcliff & McKoon, 1988; Whittlesea & Jacoby, 1990). However, the traditional account of priming assumes that the level of activation of an internal representation of a target item increases as a result of prior presentation of an identical or semantically related prime. In the case of repetition priming, this enhanced level of activation is a direct consequence of the previous occurrence of the target item. In the case of semantic/associative priming, the enhanced activation of the target item is assumed to occur as a result of spreading activation from the representation of the prime to representations of its semantic/associative neighbours in memory (e.g., Collins & Loftus, 1975; Anderson, 1983). Thus, presentation of 'DOG' speeds a subsequent response to 'CAT' because when 'DOG' becomes active in memory, activation spreads to related items such as 'CAT'. For the present purpose, the critical property of such accounts of priming is that the time required to respond to a target stimulus faithfully reflects the activation state of its internal representation. Thus, the priming effect is determined at the time the prime item is presented and is measured at the time the target is responded to. In contrast to the benefit often observed in such priming studies, several experimenters have described situations in which stimulus repetition leads to slower or more error prone responses (e.g., Kanwisher, 1987; Posner & Cohen, 1984, Tipper, 1985). In the current article, we focus on one of these empirical phenomena, now commonly known as negative priming (Tipper, 1985). …